tag:blogger.com,1999:blog-4400067025499539272024-03-13T17:36:07.085-07:00Cory Walker's blog:: A tech sandboxCory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.comBlogger18125tag:blogger.com,1999:blog-440006702549953927.post-81444136557078865352012-11-24T12:24:00.000-08:002012-11-24T12:24:48.342-08:00Out with the old, in with the newFarewell http://me.clustur.com.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgeQ8lnDaIk1OeoyUMiqlk503VLp1lENPvWAfNCAiQ7S8RhIAAW073E6yOLSjUoQRYdgAfi9HLYjUckYt4EAp0AB9SmTNKCj_F3ttDGc21mmq-ClbZ1UdIKwwXB1ydqpaZKqtOtceNdadk/s1600/garland_logo.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgeQ8lnDaIk1OeoyUMiqlk503VLp1lENPvWAfNCAiQ7S8RhIAAW073E6yOLSjUoQRYdgAfi9HLYjUckYt4EAp0AB9SmTNKCj_F3ttDGc21mmq-ClbZ1UdIKwwXB1ydqpaZKqtOtceNdadk/s1600/garland_logo.png" /></a></div>
This week I decided to move over my blog to Blogger for a few reasons, but the main ones boiled down to spam and the inconvenience of hosting my own blog.<br />
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The spam problem was outrageous, I would leave my blog for a week only to find literally hundreds of spam comments. I'd write a script to weed out the new spam comments and I'd improve the anti-spam measures and CAPTCHA's. The next week the same exact thing would happen. Note to self and others: CAPTCHA's do nothing against determined spammers. I could require people to create accounts with my blog in order to comment, but who would go to the trouble to sign up just to comment?<br />
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I also got a little tired of keeping up a server for this blog. Our internet and power go out way to much for me to trust anything on my sites. My poor little server could never keep up when a site experienced the Digg or Reddit effect, either. I also found out the hard way that server motherboards will not survive nearby strikes of lightning. That was fun.<br />
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Well, it's been real. Let's take a moment to pour over all the great memories we used to have together:<br />
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OK enough of that. We live in the present. Over the next week or so, I'll be phasing out the site and eventually shutting it down, with the exception of a few data folders that might need to stay up. This is the first post not on the old blog. Here's to change for the better.<br />
Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-3634598998332045652011-05-24T09:46:00.000-07:002012-11-22T20:45:29.136-08:00New site called Hotsteeze!I've been working on a new site on and off for the past month and the fruit of my labor has finally surfaced: <a href="http://hotsteeze.com/" style="text-align: left;">hotsteeze.com</a><span style="text-align: left;">.</span><br />
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Hotsteeze is an action sports site for logging (and sharing, if you want) tricks that you have learned. Skateboarding and other action sports, ever since they began, have been very disorganized. The best collection of tricks up to now has been all the videos scattered throughout YouTube. I've been working on cataloging as many tricks as possible. Hopefully, the database of tricks will provide a more conductive environment for discovering new tricks to learn.<br />
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Hotsteeze still has a long way to go to get to where I picture it being, but I hope to continue work on it for a long time.Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-59907075945406889462011-01-13T21:16:00.000-08:002012-11-22T20:55:07.630-08:00Logisim implementations of the CPUs in "Code"I've been looking at <a href="/2012/11/a-review-of-code-by-charles-petzold.html">"Code"</a> again, and I decided to design functioning CPUs from what I learned in it. Normally CPUs are designed in HDLs such as VHDL and Verilog, but these languages take transistors out of the equation. Since it would be my first CPU, I decided to use Logisim because it had more of a simulation interface and let design with individual transistors. I put the fruits of my labor <a href="https://github.com/cmwslw/cpu-code">on my Github</a>. The last design still needs a little of work, but all the other designs are fully functioning.
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEih86UkQKCvZlh6gliKDO2njEomfZfGVPyU75XcfQjWZcAa8tdbXs1Hw8sOFmiM82pNSLh-EfiSHPrUNZ5oJ1CAs4TEicuRI6KlMFCaM7eYWNzRsSSsTlc46D57z3eTmr9eKerH1dCBbFk/s1600/diagram.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="191" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEih86UkQKCvZlh6gliKDO2njEomfZfGVPyU75XcfQjWZcAa8tdbXs1Hw8sOFmiM82pNSLh-EfiSHPrUNZ5oJ1CAs4TEicuRI6KlMFCaM7eYWNzRsSSsTlc46D57z3eTmr9eKerH1dCBbFk/s320/diagram.png" width="320" /></a></div>
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My next project is to design a more complex CPU using Verilog. I'll write up a dedicated post on it once I make more progress. For the time being you can follow the work <a href="https://github.com/cmwslw/cpu-homebrew">at this Github page</a>. I'm also planning on writing low-level code for the Beagleboard XM I got as a Christmas present.Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-47044051598817232002010-12-21T21:21:00.000-08:002012-11-22T20:56:44.920-08:00Hack a TV to visualize music<div>
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Have an old black and white TV sitting around? I got mine after winning a raffle and it sat around for about a year unused until I decided to hack it up.</div>
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<h2>
Background</h2>
Cathode ray tubes use magnetic deflection to influence the direction of the electron beam. The phosphor-coated screen emits light when it's hit by the beam. There are two electromagnets surrounding the tube - one for vertical motion and another for horizontal motion. As it turns out, these electromagnets are surprisingly easy to hack. There are a few tutorials on instructables for this, but I figured I would make my own anyways.
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<h2>
Words of caution</h2>
Isn't it fun when the warning section is as long as the howto section?
Before I tell you to open up the TV, let me just say that TVs can be DEADLY if not handled correctly. There are high voltage capacitors in them that can hold a lethal charge for weeks after being unplugged. Don't risk it. They have the potential to severely shock you if you don't discharge them. There are many <a href="http://www.repairfaq.org/sam/captest.htm">guides</a> on the internet for this. You have been warned. This may be obvious, but note that the regular channels won't work unless you make some sort of switch or solder the wires back to where they were before. In other words, don't hack hack up grandma's old bunny-ear TV and think she won't notice next time she wants to watch Lifetime.
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Git 'r done</h2>
On to the fun stuff: Open up the TV, and make sure the capacitors are discharged. Now find the magnetic deflectors and there should be 4 wires coming from them (2 for each of the 2 electromagnets). Cut these wires close to the TV's circuit board. Now you have the wires to control the beam. You can do whatever you want with them. I chose to thread them through a hole on the top of my TV hook them up to a connector.
Once the TV is put back together, turn it on and you should see a single white dot in the middle of the screen. Don't leave this running unpowered for very long because a concentrated electron beam can burn the phosphor. This effect might even be intensified with larger TV's so be extra careful with those. Now hook up the deflector wires to a music source. I wouldn't hook it up to an iPod due to current issues, but a stereo works fine. It's possible to hook up a single channel to both the horizontal and vertical deflectors, or you can hook up the right and left channels to different ones. Play with the stereo's volume knob to get the deflection amplitude right. The final product should look like this:
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<object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/s5-PdB6oyvM?hl=en&fs=1"></param>
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<embed src="http://www.youtube.com/v/s5-PdB6oyvM?hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object></div>
<h2>
Future improvements</h2>
Instead of only hooking up music sources and getting that crazy ellipse pattern, try hooking up a sawtooth generator to one axis. This will give you a cool oscilloscope-ish device like <a href="http://www.youtube.com/watch?v=6QL6zwiBMUg&feature=related">this</a>. I bought a sawtooth-generating-IC for this purpose but I never got around to hooking it up to the CRT. Maybe I will soon...Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-37370122307360416112010-10-28T09:24:00.000-07:002012-11-22T22:41:47.986-08:00Hydrogen water rocket out of household itemsPerhaps my favorite project I've ever worked on is my hydrogen rocket. The craze started when I stumbled upon <a href="http://www.et.byu.edu/~wheeler/benchtop/hydropyro.php">an article by Dean Wheeler</a> about launching bottle rockets that used hydrogen combustion rather than a bicycle pump for power. I had already finished a <a href="/2010/08/my-electrolysis-generator.html">reliable hydrogen generator</a>, so I figured this was a good project to put it to use. I didn't have access to some tools and materials that he did, but I found some other solutions that made it work. I'll document my findings here because I believe these types of bottle rockets do not receive the attention they deserve. As far as I know, Dean Wheeler's article and mine are the only two guides about these rockets available.<br />
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NOTE: The oxyhydrogen gas described in this howto is often incorrectly called HHO and even Brown's gas. Nevertheless, the term HHO is widely used and it's a good abbreviation. Oxyhydrogen gas is essentially the 2 to 1 mixture of H2 and O2 created by the electrolysis of water. Unlike the ignition of hydrocarbons that also produce CO2, ignition of this gas produces only water and energy, nothing else. It is the purest form of combustion.
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<h1>
The rocket</h1>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhufBIZURSEccd32-SHiPVYg5J5s3id8G1sF7WJ0cedUhcUoxiDTpUzQ8UPxlpuLFx7itYuOS7b_08a8eRfW8rdH1YUz5yjOIeBLviJL-ikaNdMyC3GJxHa0BGNlsqofYkFngkTHQ_IKKs/s1600/101_6830.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="297" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhufBIZURSEccd32-SHiPVYg5J5s3id8G1sF7WJ0cedUhcUoxiDTpUzQ8UPxlpuLFx7itYuOS7b_08a8eRfW8rdH1YUz5yjOIeBLviJL-ikaNdMyC3GJxHa0BGNlsqofYkFngkTHQ_IKKs/s400/101_6830.jpeg" width="400" /></a></div>
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The rocket is separated into three logical sections:
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<li>The fins, which screw onto the bottom</li>
<li>The combustion chamber, made out of a regular soda bottle</li>
<li>The nose cone, which can carry a payload and absorb impact</li>
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<h3>
The fins</h3>
On many bottle rockets the fins are glued directly to the pressure chamber. This is mostly because bottle rocket launchers need access to the bottle's flange to hold it until launch. When I tried this method, I found that the hot glue I used weakened the combustion chamber because it slightly melted it. This never caused any catastrophic failures for me, but I still think it's not a very elegant solution. Anyways, this method is not necessary for hydrogen rockets since there is no pressure until it goes boom, so therefore the rocket does not need to be held in place. I decided to go with a modular fin design instead so I could easily change out fins, and switch them from rocket to rocket. The main body of the fin is made out of a film canister. I hollowed out the bottom with a Dremel so it was more of a pipe than a container. Similarly, I also hollowed out the screw cap so it looks like a ring but still has the threading. This screw cap ring fits nicely in the hollowed film canister, and I glued it in place with hot glue. Next you need to add the fins to the fin body. I bought some spare tupperware containers that I could use to cut out some nice and flat plastic fin shapes. I glued three fins onto the fin body at a slight angle. This angle is critical for gyroscopic stability because it spins the rocket during flight. It truly means the difference between a 50 meter and a 5 meter flight. Here are some pictures of the fins and how they attach to the rocket:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4Br0PWkvzjLAU6G3CDBbyW_-UgCLJjYOqokJTtSVdxfQ2OEUe26tP08MMnN_hr84WVA23kfEWt4a6U1c4n8DDTQD4iCU8UaYAu3foaIAoy1kFR7OCXFwvZtq-nzuIjoHqJtW1r4TRtOk/s1600/101_6804.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4Br0PWkvzjLAU6G3CDBbyW_-UgCLJjYOqokJTtSVdxfQ2OEUe26tP08MMnN_hr84WVA23kfEWt4a6U1c4n8DDTQD4iCU8UaYAu3foaIAoy1kFR7OCXFwvZtq-nzuIjoHqJtW1r4TRtOk/s200/101_6804.JPG" width="200" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJllidIlPi7sbh_RF3lf5wyAM3Q0Lw2Sa-omj1SjnbBcGO9tFNS11kQQAHCNGBUe3Wgntnx1j7WcftCDMWOBEgta5JvhmXePkAyYBSM6jnqrBQfMNfV2vbHx6SMFF1DZhYsVk3eRkDCPI/s1600/101_6805.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJllidIlPi7sbh_RF3lf5wyAM3Q0Lw2Sa-omj1SjnbBcGO9tFNS11kQQAHCNGBUe3Wgntnx1j7WcftCDMWOBEgta5JvhmXePkAyYBSM6jnqrBQfMNfV2vbHx6SMFF1DZhYsVk3eRkDCPI/s200/101_6805.JPG" width="200" /></a></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9AAyCtqFPXXFIdP14VyB326z5ceXybbyti9LtXXA2UyBrLleEX0t211D-XCEFtxHNlfyZEy75_Waejqn2Z23Qu2CeyX18XxncJ81A7iWHslSDCuYn_nqEyWgVhrnNhWH6-WwwC2Uw1t4/s1600/101_6806.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9AAyCtqFPXXFIdP14VyB326z5ceXybbyti9LtXXA2UyBrLleEX0t211D-XCEFtxHNlfyZEy75_Waejqn2Z23Qu2CeyX18XxncJ81A7iWHslSDCuYn_nqEyWgVhrnNhWH6-WwwC2Uw1t4/s200/101_6806.JPG" width="200" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEifxXUBXYygITljkaHSsoJ1OWId0mYz4SRD3w1siUUnycwX9UNdwPrfOZLLZjMbE32ucxKoOYg2-e6pa88_NopL5v3Xfmg2pdFamxmi2iiTYY9tIcAIER4GrrMV-lAbk_5XbQtoKY5NAxg/s1600/101_6803.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEifxXUBXYygITljkaHSsoJ1OWId0mYz4SRD3w1siUUnycwX9UNdwPrfOZLLZjMbE32ucxKoOYg2-e6pa88_NopL5v3Xfmg2pdFamxmi2iiTYY9tIcAIER4GrrMV-lAbk_5XbQtoKY5NAxg/s200/101_6803.JPG" width="200" /></a></div>
<h3>
The combustion chamber</h3>
The combustion chamber needs to be able to withstand significant pressure, but only for the short period of time after ignition and expulsion of the water. My combustion chamber is simply a Mountain Dew bottle. Thats all. Other soda bottles will work, but never use water bottles because they often have thin plastic and a flimsy design since they are not built for carbonation. You can decorate your rocket however you want, but there are a few marks that you should add after some experimentation: the recommended oxyhydrogen and air mixtures. You will find out what these marks are for later in the launch process section. Go ahead and mark the "HHO" line 5cm down and the "air" line 10cm down.
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgKt8BjEP3GdFcv7VZSczZTvx8qnKcvroOeq3ZMGDF7isCNVgyEVHhAi23FjDSQdwRYXZv75anqZMEi29V-eCvUdi6o7DyBfGdXloqer1DBt4wxT6SyqR9m1kGOTPzA4O1cODB1Rizo-U0/s1600/101_6802.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgKt8BjEP3GdFcv7VZSczZTvx8qnKcvroOeq3ZMGDF7isCNVgyEVHhAi23FjDSQdwRYXZv75anqZMEi29V-eCvUdi6o7DyBfGdXloqer1DBt4wxT6SyqR9m1kGOTPzA4O1cODB1Rizo-U0/s200/101_6802.JPG" width="200" /></a></center>
<h3>
The nose cone</h3>
The nose cone has several different functions. For starters, it makes the rocket more aerodynamic because otherwise it would be the butt end of the combustion chamber being forced through the air. Secondly, the nose cone adds a place to store a payload. Finally, the nose serves as a crunch zone to absorb the impact of 'landing' without damaging or weakening the combustion chamber. I use the term 'landing' loosely because the landing process is essentially a free fall then a crash. In theory the nose cone could be used to house a parachute system and avoid the 'landing' problem, but I have not attempted this. My nose cone is made out of the top part of another Mountain Dew bottle. I secure it to the combustion chamber bottle with electrical tape. You can store whatever payload you want by unscrewing the top and putting something in there. I found that the rocket can get better altitude if it has some weight (maybe about 50 grams) in the nose cone. If the rocket has no extra weight, the air drag will slow it down quickly.
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<h1>
The launcher</h1>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg17XMUqpn0l9JJ4YPO6VuN39vl_u-AWqZWsBhBhG6bVeXke80yCbPkHScK-tb6Xm6EeL1on8rqJgZ9sIWKqlvP894S0BDFypxXz6hnJ-DGoLArPYYCacpjmgSvE7xigNwdGKG94pChiKc/s1600/101_6811.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="297" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg17XMUqpn0l9JJ4YPO6VuN39vl_u-AWqZWsBhBhG6bVeXke80yCbPkHScK-tb6Xm6EeL1on8rqJgZ9sIWKqlvP894S0BDFypxXz6hnJ-DGoLArPYYCacpjmgSvE7xigNwdGKG94pChiKc/s400/101_6811.JPG" width="400" /></a></center>
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The launcher was the hardest part of the project to build. Dean Wheeler's design was much more elegant in my opinion, but there were some elements that I did not know how to build or did not have the tools to. Here are the parts you need to build the launcher (excluding basic tools like a saw and drill):
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<ul>
<li>1/2 inch PVC pipe</li>
<li>A small section of pipe that fits around the 1/2 inch PVC</li>
<li>4 PVC end caps</li>
<li>3 PVC T-joints</li>
<li>Wire</li>
<li>4 ring terminals (2 for the exterior 2 for the interior)</li>
<li>Tubing to carry the gas (I used aquarium tubing)</li>
</ul>
The size of the PVC launch tube and supports does not have any exact size, but the smaller the better. You will find out later that the smaller the volume inside the launcher, the less time it takes to get the oxyhydrogen flowing. Also not that the launcher itself does not have to be pressure-safe. Only the combustion chamber and the tip of the launch tube will be under any pressure during launch.
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<h3>
Igniter</h3>
The wiring in the launcher is for the igniter at the top:
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNtOfPrq2qLCKFwofsueODWK8BUAY3Euedl63Fe5c8iXziQO1Rvu9tb89SiX7OE8DsqDcg7kLTUg7V4OcCErngn34uetaFFuZEIVEnuv8RkeQy4Ngc4LZZbmsNAaovCCUeeJBtmtwzpDs/s1600/101_6813.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNtOfPrq2qLCKFwofsueODWK8BUAY3Euedl63Fe5c8iXziQO1Rvu9tb89SiX7OE8DsqDcg7kLTUg7V4OcCErngn34uetaFFuZEIVEnuv8RkeQy4Ngc4LZZbmsNAaovCCUeeJBtmtwzpDs/s200/101_6813.JPG" width="200" /></a></center>
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Two wires go from two different arms of the base and meet at the end of the vertical launch tube. They are sealed in with a fat blob of hot glue. These wires can provide a source of ignition in two ways. The easiest way for me is to just get a tiny steel strand from an SOS cleaning pad to act as a fuse that burns out:
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYAOxaIGkQtsgagwPNVlxxTfs79jWdtQBJEXEW-gIVSkgeLw70RCtrvOAo2yXlDsvGf6GeGVJS8sbRpBjRhndKK1SNFRlm3GWwpFqT3SdfJl-ox1sz9-QXd49cBaxzz-6N2f4f76x-14A/s1600/101_6786.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYAOxaIGkQtsgagwPNVlxxTfs79jWdtQBJEXEW-gIVSkgeLw70RCtrvOAo2yXlDsvGf6GeGVJS8sbRpBjRhndKK1SNFRlm3GWwpFqT3SdfJl-ox1sz9-QXd49cBaxzz-6N2f4f76x-14A/s200/101_6786.JPG" width="200" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVOtfr4aq9qwXA68aB40w02UVGJGYH3dLejzQSo-uLvzoFZbMVIqJCHkT6nWoky3S0rUhaR_TsHMowQDVez6-40ytUw85WQ_SL8-fFfRLLj1ueFD7u8O03OhwOMdXRxY7F2TfABtpbLjA/s1600/101_6785.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVOtfr4aq9qwXA68aB40w02UVGJGYH3dLejzQSo-uLvzoFZbMVIqJCHkT6nWoky3S0rUhaR_TsHMowQDVez6-40ytUw85WQ_SL8-fFfRLLj1ueFD7u8O03OhwOMdXRxY7F2TfABtpbLjA/s200/101_6785.JPG" width="200" /></a></center>
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Another source of ignition is using a gas grill sparking igniter that can be found at a hardware store. I found that these don't work well with long and thin wires because the spark jumped within the wire instead of at the end where I wanted it. If you want to use this method, which in theory is easier and more reliable, pick up some heavily-insulated wire.
You might be wondering about the purpose of my ring terminals. They are just an airtight way to connect the external wire to the wires on the inside. I drilled a hole through two PVC end caps for both of the connections. To make a connection, I got a bolt and first threaded the external ring terminal (wire already crimped, obviously). Next I added the actual PVC end cap, and finally the internal ring terminal. A nut holds everything tightly together and keeps it airtight. Add some rubber as an extra layer in between for an even better seal.
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitjdyBOLDTiLyuqMhAuwxpcZx3GUrW8sd4I2LmGDM6B9jslcXVAxpfRtw-27CRFNfnMB6_k_b3G25Fdl9SfF5Uw5G3iZCaKUwDDvQEMsrfUDbXytD8TfdbUPxAaPLvptIO167lS2JZn-Q/s1600/101_6810.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitjdyBOLDTiLyuqMhAuwxpcZx3GUrW8sd4I2LmGDM6B9jslcXVAxpfRtw-27CRFNfnMB6_k_b3G25Fdl9SfF5Uw5G3iZCaKUwDDvQEMsrfUDbXytD8TfdbUPxAaPLvptIO167lS2JZn-Q/s200/101_6810.JPG" width="200" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjojRk5yqkDRQUATpE1gsrmKM8fVgz3hWm7Cjwe9nfPUYX-7M68egFHIBCTTz2ndg5YlNzfozgimR_Ph7YDsqXy2loLkAslW0HJMd0ffE0s4e-XpRtC3Yz2my4IQxjUpOwqrhwBMCNalm8/s1600/101_6809.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjojRk5yqkDRQUATpE1gsrmKM8fVgz3hWm7Cjwe9nfPUYX-7M68egFHIBCTTz2ndg5YlNzfozgimR_Ph7YDsqXy2loLkAslW0HJMd0ffE0s4e-XpRtC3Yz2my4IQxjUpOwqrhwBMCNalm8/s200/101_6809.JPG" width="200" /></a></center>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUuP3BOkAjrNgwa5cHjb0vlsYf5Jzy-F7bbpXu0w-_WRaZdBqvAu6bRam5cUznG9zmv5q9rtKGqxQNljoCrDgwPXdHlcl1aWohATg2adcUENZps1Rv33uPUDUhZXILB2aV-67JOoZ10q4/s1600/101_6807.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUuP3BOkAjrNgwa5cHjb0vlsYf5Jzy-F7bbpXu0w-_WRaZdBqvAu6bRam5cUznG9zmv5q9rtKGqxQNljoCrDgwPXdHlcl1aWohATg2adcUENZps1Rv33uPUDUhZXILB2aV-67JOoZ10q4/s200/101_6807.JPG" width="200" /></a></center>
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I'll admit the inside is not a pretty sight after 2 years. This brings me to another point: use stainless steel whenever possible.<br />
<h3>
Tubing</h3>
The tubing is nothing crazy. The tube just goes right into the launcher and the gasses are pushed all the way up to a tiny hole drilled on the side of the vertical launch tube:
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhpQznuvuVN0fpTRGi6_axeZVElYwKpzBhfJzoKV5bjnR6Oo7uudlAKRy5_TiQ2Av0zcltwMJT9xMfjPtnwsgsaD2mO92zYNheM7ibVRUHZw0EwVZH4TKQ0F-YRoRQR9LbsLUtRk5n9Rv0/s1600/101_6808.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhpQznuvuVN0fpTRGi6_axeZVElYwKpzBhfJzoKV5bjnR6Oo7uudlAKRy5_TiQ2Av0zcltwMJT9xMfjPtnwsgsaD2mO92zYNheM7ibVRUHZw0EwVZH4TKQ0F-YRoRQR9LbsLUtRk5n9Rv0/s200/101_6808.JPG" width="200" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjOsKrTjf41h2tG0UbZAB7cEKvkUg7S81my_ypIyvGVyFNaib0zTucXfxVm4k0HNo-fGAX_TwsnwckqSNIeucz_AON_Qw6lNzzNgIYE6JGYVSzaHVuWxgt3MixhdqbdPuC2Yz1OG2IDZHs/s1600/101_6812.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjOsKrTjf41h2tG0UbZAB7cEKvkUg7S81my_ypIyvGVyFNaib0zTucXfxVm4k0HNo-fGAX_TwsnwckqSNIeucz_AON_Qw6lNzzNgIYE6JGYVSzaHVuWxgt3MixhdqbdPuC2Yz1OG2IDZHs/s200/101_6812.JPG" width="200" /></a></center>
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The best method would be to hook the tube directly to that tiny hole. This would avoid having all that dead space between the tube end and the hole, but I couldn't think of a good way to do it.
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<h3>
Ring stop</h3>
Pretty self explanatory. Just cut a pipe whose inner diameter is just greater than the launch tube's outer diameter, and put a screw in it. This holds the rocket at the right height until blast off.
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPO-iPkD5-60bFPiDxd6xd_HvadkQZ3_XFOAkQAVm1GK5LpnHTgnLlJSaMkC3h3K6fEhEZCLDv6iFS72p3woVZjWWMdtcILnPoWrKYfiS2fwQVmKH6oHzCthUXwu3bwrM4dv8Fk0yLpwM/s1600/101_6812_bsdf.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPO-iPkD5-60bFPiDxd6xd_HvadkQZ3_XFOAkQAVm1GK5LpnHTgnLlJSaMkC3h3K6fEhEZCLDv6iFS72p3woVZjWWMdtcILnPoWrKYfiS2fwQVmKH6oHzCthUXwu3bwrM4dv8Fk0yLpwM/s200/101_6812_bsdf.JPG" width="200" /></a></center>
<h1>
The launch process</h1>
<ol>
<li>Turn on the <a href="/2010/08/my-electrolysis-generator.html">electrolysis unit</a> and hook it up to the launcher, without the rocket on it. This helps clear out the air inside the launcher pipes so that when we do put on the rocket, it will be pure oxyhydrogen and not the residual air.
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikHPdW_Lkk4ovdFS7Gy8RloJUHDOdMB0Fk5FT_FwESuaferPNfigRjmETQ6UtOHNDZwzdLF4JBNsOYWuohz_ozdadMIA0ABS9-zpd_2JYVvdX0Opy5b2Ijw8LcqgOj-OMxA7IXrQb0wGU/s1600/101_6790.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikHPdW_Lkk4ovdFS7Gy8RloJUHDOdMB0Fk5FT_FwESuaferPNfigRjmETQ6UtOHNDZwzdLF4JBNsOYWuohz_ozdadMIA0ABS9-zpd_2JYVvdX0Opy5b2Ijw8LcqgOj-OMxA7IXrQb0wGU/s200/101_6790.JPG" width="200" /></a><center>
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</li>
<li>Wrap a fuse to the ignition wires
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjT73B56iyt-cb9AD7mZY-Ri44uY47qw6GEiLqy8sdLxnAkgOr54UOZgugyLc2ph-8S7zayTWewgvCidYVmRX-PGGnHz-3d4nxP9w0H_TcTZ26POMj3gc2oqHaxStj1YnZmwpLenap3N6A/s1600/101_6784.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjT73B56iyt-cb9AD7mZY-Ri44uY47qw6GEiLqy8sdLxnAkgOr54UOZgugyLc2ph-8S7zayTWewgvCidYVmRX-PGGnHz-3d4nxP9w0H_TcTZ26POMj3gc2oqHaxStj1YnZmwpLenap3N6A/s200/101_6784.JPG" width="200" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglc8TucqQXRWlYPwXspBAIcjCZGwLwKSJ6PxOE9NzHh5wkleLkAjNEPorv8SmbY9mepU3nHJL1ePGj5yqlwbnl_7NTSoYgY1gEwrbzFL4ct81nwpFXtbTww9sNLDHO0n9jY74KuFaf3LM/s1600/101_6785.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglc8TucqQXRWlYPwXspBAIcjCZGwLwKSJ6PxOE9NzHh5wkleLkAjNEPorv8SmbY9mepU3nHJL1ePGj5yqlwbnl_7NTSoYgY1gEwrbzFL4ct81nwpFXtbTww9sNLDHO0n9jY74KuFaf3LM/s200/101_6785.JPG" width="200" /></a><center>
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</li>
<li>Fill the rocket with water
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNF7Xej9CnhYGbq6Q0nQ3UezTnLN0-AmSxU2O_Jn_skw8LjAJVHDuFhjBSZea8ngubLENc0_FBjMJRMu76xF8ZsFb8g7Hh-tZVEI8Ge_gLpQrQwY4Rs3W1WWRcArOm1kOcqsvOXbnciOc/s1600/101_6783.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNF7Xej9CnhYGbq6Q0nQ3UezTnLN0-AmSxU2O_Jn_skw8LjAJVHDuFhjBSZea8ngubLENc0_FBjMJRMu76xF8ZsFb8g7Hh-tZVEI8Ge_gLpQrQwY4Rs3W1WWRcArOm1kOcqsvOXbnciOc/s200/101_6783.JPG" width="200" /></a><center>
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</li>
<li>Put the rocket on the launcher, with the hydrogen still flowing. Obviously, you can't just flip the rocket rightside up and put it on or the water would spill out the bottom. Instead, keep the rocket upside down and flip over the entire launcher and put the launch tube in the rocket's nozzle. Just be careful not to mess up the ignition fuse set up earlier. Now it's safe to flip everything over.
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9BzBrO4v1OdL1cQV9viKI5FOeSAqMd8q4O7p7T-DuSm6Gn_cH3iknjEz4gAcqcy460kVlxmedsX3ryxORH70r2jAtgK8WaJW9NhHILcBm7lagKng5aW0IONprkh0mimMmRD4_Q8vnFcw/s1600/101_6791.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9BzBrO4v1OdL1cQV9viKI5FOeSAqMd8q4O7p7T-DuSm6Gn_cH3iknjEz4gAcqcy460kVlxmedsX3ryxORH70r2jAtgK8WaJW9NhHILcBm7lagKng5aW0IONprkh0mimMmRD4_Q8vnFcw/s200/101_6791.JPG" width="200" /></a><center>
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</li>
<li>The displaced water will trickle out of the bottom at this time. Let the oxyhydrogen bubble in through the small hole until the water level reaches the "HHO" line. Then disconnect the oxyhydrogen tube.
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</li>
<li>Now hook up the tube to an air pump and add air until the water level reaches the "air" line. Then disconnect the tube.
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8X4HFd97R5XvYPlYnMld7hVypfOiQBAe1pR2ZYvF1RsgEoUPkGw8VpjkgyMoPdTFiBzfuLmfoNbps61mFjMEh2xIja9gyCBJoCKhz9Sc42G29WVDidXM-bv0tpMXEoGuratI0lOifHSc/s1600/101_6788.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8X4HFd97R5XvYPlYnMld7hVypfOiQBAe1pR2ZYvF1RsgEoUPkGw8VpjkgyMoPdTFiBzfuLmfoNbps61mFjMEh2xIja9gyCBJoCKhz9Sc42G29WVDidXM-bv0tpMXEoGuratI0lOifHSc/s200/101_6788.JPG" width="200" /></a><center>
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</li>
<li>Take the launcher to the launch location while unreeling the wire. Don't waste time during this part because the water sometimes slowly leaks out. Run back to the end of the wire and hook it up to a power source. This will blow out the fuse and ignite the hydrogen. BLASSST OFFF!!!!!11 The flight time is usually around 7 seconds and the apogee is roughly 200ft for my model. The easiest way to calculate maximum altitude is to just time the flight and use the classic freefall equations.</li>
</ol>
<h1>
Simulation</h1>
To calculate the temperature and pressure after combustion, use <a href="http://www.et.byu.edu/~wheeler/benchtop/h2_combustion.pdf">this thermodynamic model</a>. The most comprehensive simulator for water rockets I've found is <a href="http://www.paul.grosse.is-a-geek.com/h2orckt.htm">here</a>. Help files located <a href="http://www.paul.grosse.is-a-geek.com/wrhelp44/about.html">here</a>. It was made in the stone age of DOS but it works nonetheless (plus it gives me an excuse to use my Windows VM). Simulation is good because it can help you find the optimum water to gas ratio. It also gives you some fun stats: According to the model, my rocket has a max speed of 56m/s (125mph) and and a max acceleration of 2472.5m/s^2 (250Gs). Don't put your astronauts in this one!
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<h1>
Later tinkering</h1>
Without a parachute, the rocket darts back to earth at a surprising (and somewhat intimidating) velocity. I found that if it fell through a tree or landed wrong, one of the fins could break off. So one innovation I made was to replace the rigid hot glue join for the fin with simply tape so it would be flexible and easily replaced. Using tape is definitely easier, but hot glue is probably still the optimal join.
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<h1>
Future visions</h1>
<ul>
<li>I think putting an altitude-triggered parachute system would be really cool in this case. I've thought about it but never really done anything with it.</li>
<li>Mad props to anyone who can build such a rocket out of metal. This could handle a larger oxyhydrogen concentration for extra thrust. I think I saw an aluminum beer bottle that had potential. Those fancy Sigg drinking bottles too?</li>
</ul>
<h1>
Danger danger!</h1>
<ul>
<li>Without a parachute this thing is essentially a missile when it falls down, so keep an eye out!</li>
<li>Do not shoot at living creatures or other humans, although there's nothing wrong with some good fun ;-)</li>
<li>If there is a misfire, approach with caution and make sure the source of ignition is disconnected.</li>
<li>Don't skimp on ignition cable. My first try I used only about 4 meters of wire and my rocket blew up. In case you are wondering, I survived.</li>
</ul>
<h1>
Common problems</h1>
If you need a demonstration of things that can go wrong, see <a href="http://www.youtube.com/watch?v=khjnTCffO5g">this video</a>. The guy managed to cover just about all of them in one launch attempt. I don't have much room to talk since my first launch went no better than his did (see picture below). Just keep in mind that getting a working design can be difficult and will certainly need some tinkering to fix problems:
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<h3>
Catastrophic malfunction (boom)</h3>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJyBbCG9L8op31LeO83FmUD9tSzDgMwEgKDyzzOAb6LvhEGk7xBM5yyVmzrzjYMMtDp8wh2mT1V84fM0b0jb9nq2npovwOLJAgTP5gCu97ONXlclAGCX_emmPbT91k3z8u4vviuoAQZXw/s1600/101_6934.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJyBbCG9L8op31LeO83FmUD9tSzDgMwEgKDyzzOAb6LvhEGk7xBM5yyVmzrzjYMMtDp8wh2mT1V84fM0b0jb9nq2npovwOLJAgTP5gCu97ONXlclAGCX_emmPbT91k3z8u4vviuoAQZXw/s200/101_6934.JPG" width="200" /></a></center>
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If your rocket blows up, don't be discouraged. It happened to me on my first launch attempt (pictured above). There are two main problems that can cause an explosion rather than a launch. First of all, make sure the oxyhydrogen is diluted with air. If you do not dilute the mixture, your plastic rocket will explode for sure. Secondly, you could be using a bottle not built to withstand pressure. Flimsy water bottles like the one above will fail very easily. My first launch attempt had both of the problems described above.
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<h1>
Help</h1>
I'm sure I haven't covered everything in this article so if you have any more questions just post them in the comments. I'll get around to answering them as soon as possible. Peace out and happy rocketeering!Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-21447910099432399802010-08-18T21:33:00.000-07:002012-11-22T23:03:49.275-08:00My electrolysis generator<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNosevCkGIkEsWydbf_K1cvbBqN-Q1ieQzDjmcHuvW6wKwNCAoIUIB3NWrGdGwshoBLM-C6Q0LT3P48K63vuZ7wmbN0q2sA0oxHaORgzVoUffMdziiFRLvWotPvyDTl8C01Jybw3FiRUc/s1600/101_6780.JPG" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><br /></a></div>
It took me many many tries to design a reliable and cheap way to produce the hydrogen I needed. There are literally tons of videos of other people's designs on YouTube (just search for 'HHO generator', 'electrolysis', or 'hydrogen generator'), but some of the parts and processes were just out of reach for my budget. Some used custom-cut steel that was expensive to order. I finally found an interesting method that used off-the-shelf wall plates that were stainless steel. <a href="http://www.youtube.com/watch?v=1-5MC0_SG_w">This video</a> was the one that really gave me the idea. sirHOAX does a lot of great work with generators like these.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNosevCkGIkEsWydbf_K1cvbBqN-Q1ieQzDjmcHuvW6wKwNCAoIUIB3NWrGdGwshoBLM-C6Q0LT3P48K63vuZ7wmbN0q2sA0oxHaORgzVoUffMdziiFRLvWotPvyDTl8C01Jybw3FiRUc/s1600/101_6780.JPG" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNosevCkGIkEsWydbf_K1cvbBqN-Q1ieQzDjmcHuvW6wKwNCAoIUIB3NWrGdGwshoBLM-C6Q0LT3P48K63vuZ7wmbN0q2sA0oxHaORgzVoUffMdziiFRLvWotPvyDTl8C01Jybw3FiRUc/s200/101_6780.JPG" width="200" /></a>Anyways, stainless steel is a must otherwise you will end up with a brown soup of nastiness (iron oxide) after just a few minutes. I picked up a few of these wall plates from Lowes. I used a <a href="http://www.lowes.com/pd_103990-1571-SL13CC25_4294821476+4294819970_40?productId=3237675">blank wall plate</a>, but I also found a <a href="http://www.lowes.com/pd_103992-1571-SS23-CC10_4294821476+4294819970_40?productId=3235087&pl=1&currentURL=/pl_Steel-Stainless_4294821476%204294819970_40_">double-sized wall plate</a> that would also work if someone wants more output from their generator. As soon as I got these I used a reamer to enlarge one hole per wall plate (the hole where the screw normally fits through) to about 1.5-2cm in diameter. This is so that I can bolt the plates together. One bolt for each terminal. The reaming process was long and rubbed blisters on my hand, but I managed (it was nowhere near the work I put into hand-sawing my wind turbine blades later). I had three wall plates in all, and one terminal happened to get two wall plates while the other got one. It doesn't really matter that much.<br />
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After reaming out holes, make sure to sand the plates so there is maximum surface area for electrolysis to take place. Then assemble the plates like sirHOAX does in the video. As with all designs, you will probably have to improvise since not everyone has the same materials. Here is how my plates turned out:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKIiv_VWFM6LN4uzAQJ9NWmm8VH4JFIuTDhsBsKQgHDdga1nhlWlbXVUopKKuRR6hqMEDXeAR1igJV3OCkZQ9Cp4PoMFwsuHoK6oPayx5W0TfGYBRL5X34NPyyu4x_JmRBdc3LmtIJ_Wc/s1600/101_6776.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKIiv_VWFM6LN4uzAQJ9NWmm8VH4JFIuTDhsBsKQgHDdga1nhlWlbXVUopKKuRR6hqMEDXeAR1igJV3OCkZQ9Cp4PoMFwsuHoK6oPayx5W0TfGYBRL5X34NPyyu4x_JmRBdc3LmtIJ_Wc/s200/101_6776.JPG" width="200" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIPJRTJr3pYTQADNnphJ_xZ47NZtUN75WWuPKqK-VITeayaL6HTVHXru2VcGbqcqnn5KcQVdecgnth5he-4sDRx7q_PulBdP-g4pr8O17jidwxNkyJg9xPOwfvN9JURbNAWgbXDJq9fuI/s1600/101_6777.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIPJRTJr3pYTQADNnphJ_xZ47NZtUN75WWuPKqK-VITeayaL6HTVHXru2VcGbqcqnn5KcQVdecgnth5he-4sDRx7q_PulBdP-g4pr8O17jidwxNkyJg9xPOwfvN9JURbNAWgbXDJq9fuI/s200/101_6777.JPG" width="200" /></a></div>
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As you can see the washer I used has become very corroded, and eventually it will need to be replaced. If possible, use stainless steel for every metal part of the generator. Also shown in the above pictures is the tupperware container I mounted them in. Use the containers that have locking seals. If you use a normal container that just presses on, you will have leaks and the whole top might even pop off. Here's a closeup of how I mounted the plates:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlMas0ue29lpMThcuRo0QQi5rWCY1FayzWdty5AOBPB83zPiBOGbvd3w6-L8px7p6tFaw6Xb7zrssGzp0UCPpMTHapOiIORJXXJ0p8YHyRvTvnaUZrpc6ih8kKNgcoLEJDDbak5XEWUcI/s1600/101_6773.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="238" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlMas0ue29lpMThcuRo0QQi5rWCY1FayzWdty5AOBPB83zPiBOGbvd3w6-L8px7p6tFaw6Xb7zrssGzp0UCPpMTHapOiIORJXXJ0p8YHyRvTvnaUZrpc6ih8kKNgcoLEJDDbak5XEWUcI/s320/101_6773.JPG" width="320" /></a></div>
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I cut off a square of rubber band and poked a hole through it. I then put this in between the lid plastic and the nut. This ensures a watertight seal even though there are two holes in the lid. I also drilled a hole in the top of the lid to provide a port for the HHO. Ideally there would be one of these nozzles that hoses can attach to, but I didn't have one so I just force the clear hose through the hole:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj38hmMks1mNaZdzcsoy5ly-PCt0ilHn2xU37zR9XJ9IADyV0XGDZY4a6yq45k6O59lJA9ch6SDoe5Izq9qL4S_bZQo5EDZ9Gq8gmMN6tdaXxdjBybIvXveyc2C_IzhogWhXvO83p05q-s/s1600/101_6774.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="239" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj38hmMks1mNaZdzcsoy5ly-PCt0ilHn2xU37zR9XJ9IADyV0XGDZY4a6yq45k6O59lJA9ch6SDoe5Izq9qL4S_bZQo5EDZ9Gq8gmMN6tdaXxdjBybIvXveyc2C_IzhogWhXvO83p05q-s/s320/101_6774.JPG" width="320" /></a></div>
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You can use ordinary tap water for this, but if you need more production you can add baking soda as an electrolyte. I normally put two teaspoons of baking soda per liter. Salt also works but it precipitates this nasty green stuff. Don't use it. Next, just hook the generator up to a <a href="/2012/11/finding-power-supply-for-electrolysis.html">power supply suitable for your generator</a>. Here is my setup before being switched on:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIEa7eQ-2U5DvabggcAl5TPr_8CfG9uTsyNHACcWAldKDySU0TY6zKwhg-aN1xXT4TRbpgB4Kx_dEH499u1fu4OCwHLgKpkRBwE9YWcEi6Uga5XHtId20FZ7STI1gdHP91SuYZK_GnMfs/s1600/101_6778.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="239" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIEa7eQ-2U5DvabggcAl5TPr_8CfG9uTsyNHACcWAldKDySU0TY6zKwhg-aN1xXT4TRbpgB4Kx_dEH499u1fu4OCwHLgKpkRBwE9YWcEi6Uga5XHtId20FZ7STI1gdHP91SuYZK_GnMfs/s320/101_6778.JPG" width="320" /></a></div>
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Flip the switch on the power supply and out comes a stream of HHO (perfect for igniting):<br />
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Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-37590532944893683532009-12-16T21:51:00.000-08:002012-11-24T08:43:40.297-08:00Clustur finally releasedOver the past couple of months, I've been using what little free time I have to code a website called Clustur. It is located at <a href="http://clustur.com/">http://clustur.com</a>. The main page pretty much says it all, but it's basically a site for creating, learning, and sharing study material. I've recently used it to study for all of my exams this semester. Because it passed the test of exams for me, I can say it's helped me a ton during the process.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi3K7dM1s3tZftrT3kA9G8V27c_8gPXeMh1hgPcMQQurwJmRZMCdyLZm6e3fR7JWzUAQxtu60RsMjxTRvNaSjvM443tuGaX65mrQ1GsWNfReEWsslgACJYhoTnGWucizQGHk4ndIlcudi4/s1600/view-set-screenshot.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="125" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi3K7dM1s3tZftrT3kA9G8V27c_8gPXeMh1hgPcMQQurwJmRZMCdyLZm6e3fR7JWzUAQxtu60RsMjxTRvNaSjvM443tuGaX65mrQ1GsWNfReEWsslgACJYhoTnGWucizQGHk4ndIlcudi4/s200/view-set-screenshot.png" width="200" /></a></div>
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It's coded in Django, which helped a lot because I was able to use much of the built-in functionality. Right now it's still hosted on my home server, which is slow as molasses. Once Clustur starts getting used by people, I'll move it over to a WebFaction server. I'll also admit that it needs a bit of user interface tweaking, but for the most part everything is solid. I also have some great plans with which to extend this site, but I'll let it be a surprise when they are ready to release.Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-15883765501138516132009-10-06T22:26:00.000-07:002012-11-24T07:56:21.364-08:00Where I work<div class="separator" style="clear: both; text-align: center;">
<span style="text-align: start;">So apparently it's a thing to post workbench pictures. I guess I'll post mine too, mainly so I can remember it if my mom ever decides to move away. Anyways, here they are:</span></div>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiO7Nav5RLO7iX14lXvMB5vz6CeYxSuII5GzQYjNj609d9mdyoMDPLBRa_aPK2U6rPzW7vDpoMJHTNWMCjIaVzLZ27ap0xjGxzfCvyOcuyUYfrp-rpmWMGDrLdSr_L_osyHD12quu9sBHA/s1600/desk.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="239" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiO7Nav5RLO7iX14lXvMB5vz6CeYxSuII5GzQYjNj609d9mdyoMDPLBRa_aPK2U6rPzW7vDpoMJHTNWMCjIaVzLZ27ap0xjGxzfCvyOcuyUYfrp-rpmWMGDrLdSr_L_osyHD12quu9sBHA/s320/desk.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small; text-align: start;">My computer desk</span></td></tr>
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small; text-align: start;">Hydrogen rocket launcher to the left, broken VCR player to the right</span></td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgaj8argsn6RfF6KxGeqv7yBFP-Z5M-4BV2Ecv0qw9DZPvlsbk941L6laxzqm83ySJRWZqSjlH8rkUfGXSz6ayXdt9_2smnp3IbIVzM5nSH474nLMBnWBic6_DKAv8PaySA6PdyVfOMtfA/s1600/hydrogen_rocket.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="239" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgaj8argsn6RfF6KxGeqv7yBFP-Z5M-4BV2Ecv0qw9DZPvlsbk941L6laxzqm83ySJRWZqSjlH8rkUfGXSz6ayXdt9_2smnp3IbIVzM5nSH474nLMBnWBic6_DKAv8PaySA6PdyVfOMtfA/s320/hydrogen_rocket.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="background-color: white; color: #191a19; font-family: Verdana, sans-serif; font-size: 12px; line-height: 20px; text-align: start;">I have a modified computer PSU for the power supply. As you can see, it's hooked up to an electrolysis unit. The soda bottle thing at the top is the actual rocket, but I just noticed that the fins are screwed onto the wrong end. :)</span></td></tr>
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQhB9p9EONMUn_aqbyq6sIra2wXA5Hl1l2LQbMnvvQC1qo6JX9ULF3NezK5iffIwVE-Ydn5-kV581vStksnWK0m2Vv_DESCNSpMXrhNwM966h7ybvF5fLTYxs-QWSsrtzFkFPz-GfjIgY/s1600/junk_bin.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="239" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQhB9p9EONMUn_aqbyq6sIra2wXA5Hl1l2LQbMnvvQC1qo6JX9ULF3NezK5iffIwVE-Ydn5-kV581vStksnWK0m2Vv_DESCNSpMXrhNwM966h7ybvF5fLTYxs-QWSsrtzFkFPz-GfjIgY/s320/junk_bin.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="background-color: white; color: #191a19; font-family: Verdana, sans-serif; font-size: 12px; line-height: 20px; text-align: start;">I don't know what I'd do without my junk bin.</span></td></tr>
</tbody></table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijYM710kIy_YKtdfpqpkEP8a8ru7kqHqLTfuY6sK2jC29Z1PWOzLGKzMZsDs4XJekS_bGdUCPLz6K7PaQIQhYyikxorCj0FLk33FjgHZmCJbOD4bWA6mb2KG6B2WgEryQqEZJG3ZxzhV0/s1600/old_electronics.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="239" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijYM710kIy_YKtdfpqpkEP8a8ru7kqHqLTfuY6sK2jC29Z1PWOzLGKzMZsDs4XJekS_bGdUCPLz6K7PaQIQhYyikxorCj0FLk33FjgHZmCJbOD4bWA6mb2KG6B2WgEryQqEZJG3ZxzhV0/s320/old_electronics.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="background-color: white; color: #191a19; font-family: Verdana, sans-serif; font-size: 12px; line-height: 20px; text-align: start;">Some old electronic gizmos I have either made or taken apart. The contraption in the Zip-Lock box to the right is a PWM unit for my electrolysis unit I made a few years ago.</span></td></tr>
</tbody></table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjk3-Eo2-Ah6LuaWmAWuG2aR-bi-qKpFP5tCERChHUdzXuklm5FWIbVttqtJYPU6PE8wNrXZuGRvnY62kI-xai8mFrKZOw6yC3467s96epuYDhrbF_AabZJTjDXCM3uob8SHdMKhDo-5Jc/s1600/room.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjk3-Eo2-Ah6LuaWmAWuG2aR-bi-qKpFP5tCERChHUdzXuklm5FWIbVttqtJYPU6PE8wNrXZuGRvnY62kI-xai8mFrKZOw6yC3467s96epuYDhrbF_AabZJTjDXCM3uob8SHdMKhDo-5Jc/s320/room.JPG" width="239" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="background-color: white; color: #191a19; font-family: Verdana, sans-serif; font-size: 12px; line-height: 20px; text-align: start;">This is the electronic parts keep in my room for prototyping. I made the drawers myself from a decade old sheet of plywood sitting in the basement. It was warped as hell so I'm pretty proud.</span></td></tr>
</tbody></table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKu0V6_yJk4UIs-sRIEJ54aUiD0YBl6SkaAXeH7xnLmiIYohCAiI1iXlF7WQajBaL1R1mxIQssi-X1YRNa3IIC6EEeHNoIjFWAII-xSazbAhgD-2KJ6HzF6EuJnY6RhbqM8rRIy_JmB60/s1600/workbench.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="239" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKu0V6_yJk4UIs-sRIEJ54aUiD0YBl6SkaAXeH7xnLmiIYohCAiI1iXlF7WQajBaL1R1mxIQssi-X1YRNa3IIC6EEeHNoIjFWAII-xSazbAhgD-2KJ6HzF6EuJnY6RhbqM8rRIy_JmB60/s320/workbench.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="background-color: white; color: #191a19; font-family: Verdana, sans-serif; font-size: 12px; line-height: 20px; text-align: start;">My main workbench where I do all my soldering and stuff. Notice the old toaster oven my aunt gave me. I use it to desolder entire PCB's, but a slice of toast every now and then is good too.</span></td></tr>
</tbody></table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRtL2Nq4OPqpV58mlgoAkszxRk1JIlJADfy2dNrpmVPYpveVv6M5rkJdDCGTGmSDhwOlJbHpQckg7YSe9pLdOD55shLKrGGO1m6fZq6Q3VIWPVI2_zDThY2tzpjZsHhY6dyUCA-NSsCYU/s1600/workroom.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="239" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRtL2Nq4OPqpV58mlgoAkszxRk1JIlJADfy2dNrpmVPYpveVv6M5rkJdDCGTGmSDhwOlJbHpQckg7YSe9pLdOD55shLKrGGO1m6fZq6Q3VIWPVI2_zDThY2tzpjZsHhY6dyUCA-NSsCYU/s320/workroom.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="background-color: white; color: #191a19; font-family: Verdana, sans-serif; font-size: 12px; line-height: 20px; text-align: start;">The workroom/workout room that's my second home. Notice the old treadmill and Bowflex that my family never uses :).</span></td></tr>
</tbody></table>
<br />Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-72752676791404028712009-08-06T22:18:00.000-07:002012-11-24T08:03:54.477-08:00Collection of some old programming projectsI decided to upload many of my favorite programming projects I worked on years ago back in my Windows days. Yes, almost 1GB of code. The size of my old code directory totals almost 4GB, but I'm only including the most developed projects here. I'm releasing this code in the hopes that someone will find it useful. But please keep in mind that this is unsupported, undocumented, and (largely) uncommented code. Keep in mind that this code was written when I was about 12 or 13 so please don't use this as a measure of my current programming skills. I am releasing all of this code under the <a href="http://www.gnu.org/licenses/gpl.html">GNU Public License</a>. Use it as you wish. Enjoy!<br />
<br />
<a href="http://me.clustur.com/data/oldcode/">Here is the link!</a><a href="http://www.blogger.com/blogger.g?blogID=440006702549953927"></a>Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-84521166933812035822009-07-20T22:30:00.000-07:002012-11-14T22:31:35.611-08:00SSH into a computer using an iPhone or iPod TouchMany people are aware that they can SSH into their iPod or iPhone from their computers. The fact that the iPhone can be an SSH client is often overlooked, though. It can even authenticate with RSA keys. In this guide I will demonstrate how to set up an iPhone or iPod to SSH into a computer with an RSA key.<br />
<br />
This guide assumes that your device is jailbroken, and the OpenSSH package is installed. OK, so let's get down to business. The first step is to SSH into your device using:
<br />
<div class="code-block">
<pre>ssh mobile@[YOUR_IPODS_LAN_IP]
</pre>
</div>
After that, you will be in mobile's home directory. You can then generate the local RSA key using:
<br />
<div class="code-block">
<pre>ssh-keygen -t rsa
</pre>
</div>
You will need to just press enter at all prompts. You should now have a file called id_rsa.pub in the hidden .ssh directory. The next step is to copy the id_rsa.pub file onto the computer you want to be able to SSH into. The method does not matter here, and it may or may not be a two step process. The home folder of the user you want is the easiest place to put id_rsa.pub. Here is an easy way to copy it from your device to the destination via SCP:
<br />
<div class="code-block">
<pre>scp .ssh/id_rsa.pub username@hostname.com:~
</pre>
</div>
At this point you can exit out of your device SSH session. Once id_rsa.pub is in the home directory that you want on the server, somehow log in as that user and run:
<br />
<div class="code-block">
<pre>cat id_rsa.pub >> .ssh/authorized_keys
</pre>
</div>
This will copy the public key into the list of keys that the SSH server will accept. After this step you can delete the id_rsa.pub file from your home folder. And that is the last step! If everything worked correctly you should be able to open up Terminal on your jailbroken iPod/iPhone and SSH into the computer you set this up on!
<br />
<div class="code-block">
<pre>ssh <code>username@hostname.com</code>
</pre>
</div>
If you have any questions/comments, feel free to post in the comment sections. I'll do my best to answer.Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-67164000389405322042009-06-09T08:16:00.000-07:002012-11-24T08:59:00.658-08:00Apache subdomains with DynDNS or No-IPWhen I was setting up my server, I was faced with the problem of configuring subdomains to work with a dynamic DNS service such as DynDNS or No-IP. I recently had a user on the Ubuntu Forums ask me how I ended up getting things to work, so I wrote this article to explain.<br />
<br />
The first step is to configure settings with your dynamic DNS service. The following instructions are for No-IP, but they should be very similar to other services such as DynDNS:
<br />
<ol>
<li>Navigate to the settings page for your domain.<br /> </li>
<li>Find the "Enable wildcards" option and enable it. This directs all domain requests, no matter the subdomain, to Apache. Here is a picture for No-IP:
</li>
</ol>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwHZZzf0hyphenhyphenM6F7V22CST6mh-jBkR_bwUjn4XFyJMsaYTIi5FlTi_8bmHgMQxBb60b-g-b-94NgkhfB0YAyRSHYuO-1IV-66byfyyRe-yLobu-gLkYS_Wn5urnfN1ZivyFANCtI3XomHyA/s1600/Screenshot-No-IP+Members+Portal-+Managed+DNS+-+Update+host+-+Mozilla+Firefox.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="156" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwHZZzf0hyphenhyphenM6F7V22CST6mh-jBkR_bwUjn4XFyJMsaYTIi5FlTi_8bmHgMQxBb60b-g-b-94NgkhfB0YAyRSHYuO-1IV-66byfyyRe-yLobu-gLkYS_Wn5urnfN1ZivyFANCtI3XomHyA/s400/Screenshot-No-IP+Members+Portal-+Managed+DNS+-+Update+host+-+Mozilla+Firefox.png" width="400" /></a></div>
<br />
After configuring your provider, next we need to configure Apache. In order to direct to the right location on the server, you need to configure Apache to know where each subdomain should be directed.
<br />
<ol>
<li>On your server, navigate to <code>/etc/apache2/sites-available</code>. This path is for Ubuntu, you will probably need to work with httpd.conf on other systems. This is where Apache gets information about sites and subdomains on Ubuntu.<br /> </li>
<li>If you have not already done so already, create a new .conf file. Although you can name it whatevery you want, it is useful to name it with the format, [yourdomain.com].conf. This file will be used instead of <code>default</code> because it is easer (for me at least) to start from scratch for something like this.<br /> </li>
<li>Open up the file, and add the following lines:
<pre><VirtualHost *>
DocumentRoot /var/web/www
</VirtualHost></pre>
This is the main entry, it directs all of the undefined subdomains (which we will define later - be patient) to /var/web/www. Of course, you will need to add your own configuration like log files; this is just the bare minimum to get you going. The path can be whatever you like. Note that your changes will not be added until step #6, so hang out.<br /> </li>
<li>Now you can define other subdomains and their paths. Here is an example for foo.clustur.com:
<pre><VirtualHost *>
ServerName foo.clustur.com
DocumentRoot /var/web/foo
</VirtualHost></pre>
Notice the only difference is the ServerName attribute. You can add as many of these directives as you would like into your .conf file.<br /> </li>
<li>Now we need to enable the settings we just made:
<pre>sudo a2dissite default
sudo a2ensite [yourdomain.com].conf</pre>
The first line disables the old default configuration file, and the second line enables your new .conf file, whatever you named it.<br /> </li>
<li>Finally, we can restart apache:
<pre>sudo /etc/init.d/apache2 graceful</pre>
Now all of your subdomains should work! If you're stumped or have any suggestions, please feel free to comment - I'll do my best to help you out.</li>
</ol>
Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-79480599305407285472009-06-05T08:10:00.000-07:002012-11-24T08:58:48.785-08:00Cloning drive copies partition UUID'sMy server used to have a 16GB hard drive, and did not receive regular automated backups. I wanted to upgrade the drive to an 80GB one and use the old drive for automatic backups. This switch required that I somehow move the entire server installation from the old to the new, larger drive. So I decided to use a tool called <a href="http://clonezilla.org/">Clonezilla</a>. I cloned the old drive onto the new drive, and set the new drive to the master. Booting up with the new drive worked fine. I put in the old drive (which still had the server installation) as a slave for backups. It was then that I ran into an interesting problem: no matter what I did, the old drive would always boot instead of the new one. After some probing, I found out that GRUB was run on the new drive, but it always pointed to the old drive. After about 6 hours of banging my head against the wall, I finally figured out that the <a href="http://en.wikipedia.org/wiki/Universally_Unique_Identifier">UUIDs</a> for the two drives were the same since they were cloned. Instead of using the generic <code>(hd0,0)</code>, the Ubuntu distribution uses UUIDs by default to point to the drive that should be booted from. The UUIDs were not so universally unique anymore, and GRUB got confused and booted the old drive. So I guess the moral of the story is always make sure you change the UUIDs whenever a cloned drive is used. Anyways, sorry if this notice came too late. I hadn't expected to run into such trouble.<br />
<br />
For reference, here's the steps to change a duplicate UUID:
<br />
<ol>
<li>Run <code>uuidgen</code> to generate a new UUID.<br /> </li>
<li>Type in <code>tune2fs /dev/hdaX -U [newuuid]</code> to actually update the partition's UUID. Be sure to replace <code>hdaX</code> with the correct partition and <code>[newuuid]</code> with the UUID given by uuidgen.<br /> </li>
<li>Verify that the UUID was changed properly with <code>vol_id /dev/hdaX</code>.</li>
</ol>
All bundled up, the command is <code>uuidgen | xargs tune2fs /dev/hdaX -U ; vol_id /dev/hdaX</code>. If you just need to clear out the old drive with the duplicate ID, reformatting it would do the trick, too.<br />
<br />
If some of you are wondering, this is the source of the recent downtime my server went through. The sites that were affected included this one, and my <a href="http://nxtpp.clustur.com/">NXT++</a> and <a href="http://l4n.clustur.com/">Linux4nano</a> wikis. The sites were on and off for about a period of 24 hours. I hope this short tutorial helps some people solve the problems I experienced.Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-70453390698389429432009-05-17T09:37:00.000-07:002012-11-24T09:51:25.506-08:0010 ways to learn how computers really workSo you know how to install Microsoft Office, upgrade drivers, and maybe even do a little overclocking or programming here and there. But have you ever wanted to know more about a computer - how it really works? Here are just a few ways that you can learn a bit more about the mysterious machine.
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRMqVGm2YHg9OWJGst0BL5Y3fs0rM1Ox2FD_YaGP6vL7tYDJmt7_WSeo7e8v-AuYRDCEv9pxdnk-d8NoMlL0rBjeA5G5LHezY0P0kM5JAUt-tW1iqr-yhn4R8l9QddQf-JEewk5Lx5Uzc/s1600/computer_guts.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="120" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRMqVGm2YHg9OWJGst0BL5Y3fs0rM1Ox2FD_YaGP6vL7tYDJmt7_WSeo7e8v-AuYRDCEv9pxdnk-d8NoMlL0rBjeA5G5LHezY0P0kM5JAUt-tW1iqr-yhn4R8l9QddQf-JEewk5Lx5Uzc/s200/computer_guts.png" width="200" /></a></div>
<ol>
<li><strong>Open up your computer</strong>
This is a fun, interactive way to learn what's really under the hood. You can learn a lot by opening something up and picking out what the different parts do. <a href="http://www.computerhope.com/issues/ch000765.htm">Here</a> is a link that explains some of the details. Although opening a computer might be a little intimidating for some people, keep in mind that computer parts are very durable, even if you have a laptop. It's also safe, as long as you unplug it from the wall first! :-)
<br /> </li>
<li><strong>Set up a home server with an old computer</strong>
Pretty much everyone has at least one old piece of crap computer laying around. One of the best uses for a computer like that is to <a href="http://lifehacker.com/software/feature/how-to-set-up-a-personal-home-web-server-124212.php">set it up as a home web server</a>. It can teach you a lot about the Internet and also let you host your own site!
<br /> </li>
<li><strong>Install Linux</strong>
This can teach you tons about how a computer boots and what an operating system really does. Installing a Linux distro like <a href="http://ubuntu.com/">Ubuntu</a> is good since everything is open source. Linux also exposes many advanced and low level functionality that Windows and OSX try to build a wall around. By using Linux, you can tinker and examine with parts that are hidden in other operating systems.
<br /> </li>
<li><strong>Upgrade your PC components</strong>
Has your computer gotten too slow to run the latest games or applications, or do you just want a general speed up? Instead of buying a brand new $500 computer, try <a href="http://www.daileyint.com/hmdpc/pcs.htm">upgrading individual components</a> like the RAM, graphics card, or CPU. This can be much cheaper, and is not as difficult as you may think.
<br /> </li>
<li><strong>Learn a low-level programming language</strong>
Everything that runs on a computer was written with a programming language. Low-level languages like <a href="http://en.wikipedia.org/wiki/C_(programming_language)">C</a> and <a href="http://en.wikipedia.org/wiki/Assembly_language">Assembly</a> teach you the most because they are more connected to the computer's memory. C is a great language to learn, but if you really want to understand computers, learn Assembly.
<br /> </li>
<li><strong>Do things the 'manual' way</strong>
In a world of automatic everything, it is nice do do things the manual way every once and a while. Too much automation can cause you to forget what really happens in the background. Try <a href="http://www.tuxfiles.org/linuxhelp/mounting.html">mounting your flash drive manually</a>, or <a href="http://www.tuxfiles.org/linuxhelp/softinstall.html">compiling and installing that latest snapshot from source</a>. Who knows? You might end up needing to do these sorts of things manually if something is not working.
<br /> </li>
<li><strong>Write a barebones kernel</strong>
What better way to understand an OS than to make one yourself! Making a simple kernel is not as hard and scary as many people think it is. Of course, if you want to make your kernel able to do something useful, be prepared to do a lot of reading. <a href="http://www.osdev.org/">Here</a> is a great place to start out with OS programming.
<br /> </li>
<li><strong>Read a book on digital electronics</strong>
It's hard to understand a computer if you don't know how different computer parts can communicate with each other. I highly recommend <a href="http://www.amazon.com/Digital-Electronics-Demystified-Myke-Predko/dp/0071441417">Digital Electronics Demystified</a>, because it teaches you all the essentials. You can also use this knowledge to build some neat circuits.
<br /> </li>
<li><strong>Program a microcontroller</strong>
This requires a light background in electronics, but <a href="http://www.avrtutor.com/tutorial/thermo/welcome.php">programming a microcontroller</a> can be fun and useful. You can program microcontrollers in C or Assembly. You can also make a bunch of neat circuits with it, too.
<br /> </li>
<li><strong>Read the book 'Code'</strong>
This is a really great book about how computers really work. You can find a review of it <a href="http://www.blogger.com/node/5">here</a>.
</li>
</ol>
Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-90042217219531534942009-05-17T09:27:00.000-07:002012-11-24T09:30:12.080-08:00Wolfram Alpha: As useful as Google?Just hours ago, <a href="http://www.wolframalpha.com/">Wolfram|Alpha</a> was launched. If you have not been there already, <strong>check it out</strong>! This revolutionary site was just too exiting for me not to write about it. Wolfram|Alpha essentially makes libraries and libraries of knowledge available at a click of a mouse. Wolfram|Alpha is not a search engine, it is completely different and unique. You won't know it until you try it. This definitely won't replace Google for me, since the two products solve two different issues. Nonetheless, it will definitely be useful for school stuff. I'm not sure if it has much appeal for the normal Internet users, though.<br />
<br />
<a href="http://www65.wolframalpha.com/screencast/introducingwolframalpha.html">Here</a> is a link to a demo by Wolfram himself.Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-13962667608681008482009-05-16T11:21:00.000-07:002012-11-24T11:22:01.321-08:00Enabling advanced searching in Drupal<a href="http://drupal.org/handbook/modules/search">Enabling searching</a> in Drupal is easy enough, but a lot of people have trouble enabling the advanced searching capabilities in Drupal. Once an administrator enables a search box, he or she will be able to access the advanced search form on the search page. The problem, however, is that normal and unregistered visitors cannot see it.<br />
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To fix this problem you need to navigate to Administer -> User Management -> Permissions. Scroll all the way down to the 'search module' section and check the two checkboxes for advanced searching like so:<br />
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If you just want registered users to access advanced searching, just check the rightmost box. Well that's about it! Now even non-administrators can use the advanced search in Drupal:
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzwWsef-WD6sVsqYJmqDbVaoMivSy-WPatvdmgeU7ZcE_st6SC_NUYoZlx8iVBLB3byARy3EVKuHG_rGmZgtvxoGqw1i-pOvFuK8wuJnR3hKKmEciN8iwrfaGFXyPaxVPDLU6VG28aprg/s1600/Screenshot-Search+-+Clustur+-+Mozilla+Firefox.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" height="237" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzwWsef-WD6sVsqYJmqDbVaoMivSy-WPatvdmgeU7ZcE_st6SC_NUYoZlx8iVBLB3byARy3EVKuHG_rGmZgtvxoGqw1i-pOvFuK8wuJnR3hKKmEciN8iwrfaGFXyPaxVPDLU6VG28aprg/s400/Screenshot-Search+-+Clustur+-+Mozilla+Firefox.png" width="400" /></a></div>
<br />Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-26874308986417428772009-05-05T22:55:00.000-07:002012-11-22T23:12:24.690-08:00Finding a power supply for electrolysisWhen I started getting interested in electrolysis, I faced the problem of finding a power supply suitable for the high currents required. At first I was using wall-warts that could only supply an amp or so. My electrolysis units started consuming more and more current, so I burnt out about three of those. I then decided it was time for me to get a better power supply. I had heard of many people using car batteries, but while those can supply a lot of current, they are expensive and cumbersome to charge. If you do use a car battery for electrolysis, you basically have to get a deep-cycle one to prevent damage when it is drained. I also searched for bench power supplies meant for electronics, but those were too expensive and did not provide enough amps. Bench power supplies are very regulated, which isn't that much of a deal when you aren't dealing with sensitive electronics. I finally stumbled upon a solution that would satisfy all my needs: a computer power supply.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1I4h155pOTl_g9Mqh3uySJBTSQSBMByQYCPG4OPTJpqT_7fTLPz8oJ-uUJLIY9_ykpe6ut5XvaljpUe-45iK9pmp2uLvzFKmnE_OUJ0on5effAW8f_EZ4MgqSlGKXajSVPPqH_FtDMXE/s1600/100_0769.JPG" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1I4h155pOTl_g9Mqh3uySJBTSQSBMByQYCPG4OPTJpqT_7fTLPz8oJ-uUJLIY9_ykpe6ut5XvaljpUe-45iK9pmp2uLvzFKmnE_OUJ0on5effAW8f_EZ4MgqSlGKXajSVPPqH_FtDMXE/s200/100_0769.JPG" width="200" /></a>A computer power supply is cheap, and powerful. Computer PSUs also provide the voltages I need, such as 5 and 12 volts. There are varying degrees of quality when it comes to power supplies. There are extremely regulated, stable, and expensive power supplies intended for sensitive computer components, and there are cheap power supplies that aren't so regulated and can pose a threat to the electronics they power. I would never put a cheapo PSU in my computer, but they are perfect for the brute force needs of electrolysis. I picked up a 450W ATX PSU on <a href="http://computers.shop.ebay.com/items/Standard-ATX-Power-Supplies__W0QQ_armrsZ1QQ_dmdZ1QQ_mdoZComputersQ2dNetworkingQQ_msppZQQ_pcatsZ42017Q2c158884Q2c3667Q2c58058QQ_sacatZ80174">eBay</a> for only $30 USD. 450W is plenty for my generator, but if you have a huge one, I would recommend getting a higher wattage or better yet just get a second one. You should find out the amperage your generator consumes to find out what power supply fits your needs. Be aware that the different rails (5V, 12V, 3.3V) all supply different amounts of current. Make sure your power supply is ATX, not just AT.<br />
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Once you have found a power supply, the next step is modifying it so it is suitable for bench power supply use. A computer PSU cannot work outside of a computer without simple modifications. There is a great wikiHow article about how to modify it <a href="http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply">here</a>. The step where you bundle wires with the same voltage is important. If you don't, running 13 amps through a single wire will cause it to glow orange, incinerate the insulation, and eventually turn to molten copper. Trust me, burnt insulation does not smell good. (Not that this has ever happened to me, though! :-) ) In addition, I did not have to add a dummy load resistor, but some PSUs require it. Most cheapo power supplies do not require one. Also, Instead of using banana plugs, I decided to use ring terminals instead. Banana plugs would probably be a better choice if you can use them.
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This is how I hook my generator up to the power supply. I basically solder the wires securely to a bolt and use a nut to fasten it on to the power supply ring terminal. Its important to get good solid contact between the terminals. If the current is being funneled through just a small area of contact, it might heat up or possibly weld itself together if the current is high enough. I make sure all exposed metal is covered by tape. Ideally these terminals would not be dangling around but so far I haven't bothered to fix this yet.<br />
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So far, my power supply has worked great, despite the constant abuse I put it through. If you have any questions about the process, feel free to ask in the comments.<br />
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Good luck!Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-79561761555321668802009-05-04T11:26:00.000-07:002012-11-24T11:45:49.408-08:00phpMyAdmin complains about the 'controluser' after upgradeWhen recently upgrading my server to Ubuntu 9.04, phpMyAdmin was also upgraded to version 5.0.75. When I loaded up the new version, I was alarmed to find a new error message that read:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvqIbo4tLLMVERwh2ByU4WM-tUx777wcf7oGozjOZWb_vRkONEZdRVwhcfvEo6piIpAoT-t0NZfVOD1dGIXZPgbBM5aOfChZj203TNk-MvDA2faxzb10ExU62DvRub-CpPtDh5-9TgtVY/s1600/logo.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvqIbo4tLLMVERwh2ByU4WM-tUx777wcf7oGozjOZWb_vRkONEZdRVwhcfvEo6piIpAoT-t0NZfVOD1dGIXZPgbBM5aOfChZj203TNk-MvDA2faxzb10ExU62DvRub-CpPtDh5-9TgtVY/s1600/logo.png" /></a></div>
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<code>Connection for controluser as defined in your configuration failed.</code><br />
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It turned out this error was due to the fact that version 5 of phpMyAdmin adds support for a new feature known as a <a href="http://www.phpmyadmin.net/documentation/#linked-tables">linked-tables infrastructure</a>. This infrastructure allows for new features such as bookmarks, comments, SQL-history, PDF-generation, and field contents transformation. The problem was that this new feature is enabled by default, with generic credentials set up for the controluser. If you don't have your database set up for the infrastructure, you will see the error. I have no use for these new features, so I'd rather just not mess with them. If you do want to enable the advanced features, <a href="http://www.pyrosoft.co.uk/blog/2008/04/30/installing-phpmyadmin-advanced-features-on-ubuntu/">here</a> is an informative post about doing so on Ubuntu. If you just want to disable the linked-tables infrastructure, which is often the easiest and least intrusive way, just follow these steps:
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<li>Type <code>nano /etc/phpmyadmin/config.inc.php</code> in the Linux terminal. You can substitute nano for vi or your favorite text editor.
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<li>Find the two blocks of text that read:
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<pre>$cfg['Servers'][$i]['controluser'] = $dbuser;
$cfg['Servers'][$i]['controlpass'] = $dbpass;
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one is near the top embedded in an if statement, and the other is towards the bottom. The text is not exactly the same for each block, but <code>$cfg['Servers'][$i]['controluser']</code> is what matters. The block that is actually used by phpMyAdmin depends on your setup, but just for simplicity we will apply the change to both.
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<li>Just comment out those four lines by adding a // in front of each one.
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<li>Save, and the error should disappear next time you access phpMyAdmin. If you are still having trouble, feel free to post a comment.</li>
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Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0tag:blogger.com,1999:blog-440006702549953927.post-54769154600301855942009-05-01T09:15:00.000-07:002012-11-24T11:23:17.704-08:00A review of 'Code' by Charles Petzold<div class="separator" style="clear: both; text-align: center;">
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Normally when I open a book that explains how computers work, I get little illustrations of the CPU, RAM, hard drive, and graphics chip. This is a great way to educate people about computers, but I have always wondered how computers <em>really</em> worked - from the transistor up.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjOoN0AgekmJT28P1e4E5HlFWlhnS-UFrAq_inWnnjQf8M9rmqX-zhZr1CzTAyOzNMdLSbvKcb-wv3naEd98Xm2wJQuN12r3L1e6mFtrsoRNAX5yYBFBVxhZRdTeatUETPUbgBLP0iBAKM/s1600/bookcover.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjOoN0AgekmJT28P1e4E5HlFWlhnS-UFrAq_inWnnjQf8M9rmqX-zhZr1CzTAyOzNMdLSbvKcb-wv3naEd98Xm2wJQuN12r3L1e6mFtrsoRNAX5yYBFBVxhZRdTeatUETPUbgBLP0iBAKM/s200/bookcover.png" width="131" /></a>In <a href="http://www.amazon.com/Code-Language-Computer-Hardware-Software/dp/073560505X"><em>Code</em></a>, Charles Petzold avoids the over simplifications of other books altogether. Petzold starts by explaining the use of Morse code to talk to friends using flashlights, and moves on to relays, logic gates, flip flops. With each chapter Petzold adds another layer to your knowledge. At the end of the book you will understand the inner workings of a computer from the simplest to most complex components. After reading this book, I have all the knowledge I'd need to build a simple computer from the ground up.<br />
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One of my favorite characteristics of Petzold's writing is his foolproof explanation and careful attention to detail. As examples, Petzold uses accurate and interesting real world scenarios. A particular favorite of mine was his description of how a barcode works, to help explain the binary system. Because <em>Code</em> explains things from the very lowest levels first and one step at a time, very little previous knowledge of computers is required. I've enjoyed reading this book so much - hopefully you will to! I highly recommend it to anyone wanting to know what really goes on inside the computer.<br />
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I might even start and post a project where I actually build a computer from scratch. For the time being, here is a very interesting link to a webpage describing such a project: <a href="http://www.homebrewcpu.com/">http://www.homebrewcpu.com/</a><br />
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UPDATE: I published some Logisim implementations of the CPUs described in this book <a href="http://me.clustur.com/node/80">here</a>.Cory Walkerhttp://www.blogger.com/profile/15041243390915737767noreply@blogger.com0