I used an old CNC power supply transformer that steps 120VAC down to 30VAC with a lot more amps. I hooked up its secondary coil to some carbon rods from carbon-zinc batteries and, using .22 caliber shells as electrode holders, adjusted the rods so that they touched. The resulting arc was so hot it warmed my hands from 6" away! Even though the arc itself was only ~2mm long, it was hot enough to melt copper and tin. It was also about as bright as burning magnesium, so I had to use welding goggles to protect my eyes. That being said, I had an extreme amount of fun with this little experiment. Check out the video to experience the awesomeness of raw electricity!
Experiment 31: Carbon Arc Light
This project was utterly, fantastically awesome! I was able to harness the crazy power of electricity to create an intensely bright arc light. Electric arcs are so bright that they can be used in anti-aircraft searchlights and so hot that they can be used to melt tungsten (highest melting point metal). Mine doesn't do either of those things... yet.
I used an old CNC power supply transformer that steps 120VAC down to 30VAC with a lot more amps. I hooked up its secondary coil to some carbon rods from carbon-zinc batteries and, using .22 caliber shells as electrode holders, adjusted the rods so that they touched. The resulting arc was so hot it warmed my hands from 6" away! Even though the arc itself was only ~2mm long, it was hot enough to melt copper and tin. It was also about as bright as burning magnesium, so I had to use welding goggles to protect my eyes. That being said, I had an extreme amount of fun with this little experiment. Check out the video to experience the awesomeness of raw electricity!
I used an old CNC power supply transformer that steps 120VAC down to 30VAC with a lot more amps. I hooked up its secondary coil to some carbon rods from carbon-zinc batteries and, using .22 caliber shells as electrode holders, adjusted the rods so that they touched. The resulting arc was so hot it warmed my hands from 6" away! Even though the arc itself was only ~2mm long, it was hot enough to melt copper and tin. It was also about as bright as burning magnesium, so I had to use welding goggles to protect my eyes. That being said, I had an extreme amount of fun with this little experiment. Check out the video to experience the awesomeness of raw electricity!
Experiment 30: Miniature Wimshurst Machine
Inspired by a museum show on electricity I viewed while on Christmas vacation, I set about to build a small Wimshurst machine. If you know me well, you will know that I like bigger and better and more dangerous, etc., so this small machine is only a prelude to the large machine I intend to build. I hope to achieve 2 to 3 inch sparks. Heh heh heh.
Anyhow, this machine works by using two counter-rotating discs to gather and transfer static electricity into a capacitor called a Leyden jar. Once the charge in the Leyden jar is high enough, the electricity bridges the spark gap with a loud SNAP and some really cool sparks. The sparks produced from this machine are very short but are about as bright as lightning. The machine is quite fun to use.
Watch the video to see it in action! Be warned, though, that the video does not truthfully depict the sparks. They look much better in real life.
Anyhow, this machine works by using two counter-rotating discs to gather and transfer static electricity into a capacitor called a Leyden jar. Once the charge in the Leyden jar is high enough, the electricity bridges the spark gap with a loud SNAP and some really cool sparks. The sparks produced from this machine are very short but are about as bright as lightning. The machine is quite fun to use.
Watch the video to see it in action! Be warned, though, that the video does not truthfully depict the sparks. They look much better in real life.
Laser Cutter Build Night: PiKnife Completed!
Tonight, I officially finished PiKnife, the Raspberry Pi-based laser cutter that cost $3.39. While some minor issues still exist, for the most part, they do not affect engravings and cuttings. Thus, for the present, PiKnife has been successfully completed - finished, but not shelved. I may modify it in the future for better results and such, but right now, FIRST robotics is starting up, so I am eager to devote all my waking hours to building robots.
I am quite happy with how PiKnife has turned out. It can successfully engrave and cut from gcode files generated by common image drawing programs and is accurate and precise. It does not need constant tweaking in order to work correctly, which is something I strive for in my projects. Looking forward in the future, I am excited to see how PiKnife will evolve and morph.
To wrap this build log up, I thought I would share my code, a picture of the finished laser cutter, and a model PiKnife cut out of foam. Here are the pictures:
I am positively exuberant at holding the finished Spitfire MKII miniature model. It looks awesome! I love the detail and the satisfaction at payoff from a job well done. I got the CNC files from here. If you would like to use, modify, or view my final PiKnife code, check out each file here, here, and here. (The limit switches are unimplemented.)
I guess that's ta-ta for now, but perhaps in the future PiKnife will improve once again. :)
I am quite happy with how PiKnife has turned out. It can successfully engrave and cut from gcode files generated by common image drawing programs and is accurate and precise. It does not need constant tweaking in order to work correctly, which is something I strive for in my projects. Looking forward in the future, I am excited to see how PiKnife will evolve and morph.
To wrap this build log up, I thought I would share my code, a picture of the finished laser cutter, and a model PiKnife cut out of foam. Here are the pictures:
I am positively exuberant at holding the finished Spitfire MKII miniature model. It looks awesome! I love the detail and the satisfaction at payoff from a job well done. I got the CNC files from here. If you would like to use, modify, or view my final PiKnife code, check out each file here, here, and here. (The limit switches are unimplemented.)
I guess that's ta-ta for now, but perhaps in the future PiKnife will improve once again. :)
Laser Cutter Build Night: Almost Complete!
Tonight was an extremely productive and satisfying build night. After the success of last night, I absolutely had to see this project through. I did quite a few things:
First, I fixed the sticking problem, hopefully once and for all. I took apart the entire XY table sled assemble and cleaned everything with rags, water, and a toothbrush. Then, I generously slathered everything in mineral oil. Quite generously, actually. The parts were so slippery they nearly jumped out of my hand. After putting everything back together, the problems dissolved and haven't reared their ugly heads since. I am quite happy about this, since the X axis had become unusable due to its sticking problem.
I also added anti-backlash code. To do this, I set a variable to keep track of the direction the motor moved last. If the new direction for the motor to move is opposite its last direction, the motor moves a few hundred extra microsteps in the new direction to counteract the backlash. It does not update its position variable, because the actual axis has not moved relative the the laser beam. I was able to use this new functionality quite effectively to eradicate all backlash on my X and Y axes.
Finally, I did some test code. The axes never stuck and my circles came out perfectly circular. I also figured out how to do complicated drawings using Inkscape and the laser cutter extension, so I had my machine do an amazing job of drawing its name (click the picture for a bigger view):
That engraving of the name "PiKnife" represents so much - the culmination of hours and hours of work. It means so a lot to me to finally have a beautiful piece of proof that this actually does stuff. I was truly amazed when I saw such fine, curving lines meeting up perfectly. I look forward to a lot of future use of this machine.
My next goals will be to add in the limit switches and look into the timing issues. However, neither of these affected the engraving above, so I am currently a very happy engineer.
First, I fixed the sticking problem, hopefully once and for all. I took apart the entire XY table sled assemble and cleaned everything with rags, water, and a toothbrush. Then, I generously slathered everything in mineral oil. Quite generously, actually. The parts were so slippery they nearly jumped out of my hand. After putting everything back together, the problems dissolved and haven't reared their ugly heads since. I am quite happy about this, since the X axis had become unusable due to its sticking problem.
I also added anti-backlash code. To do this, I set a variable to keep track of the direction the motor moved last. If the new direction for the motor to move is opposite its last direction, the motor moves a few hundred extra microsteps in the new direction to counteract the backlash. It does not update its position variable, because the actual axis has not moved relative the the laser beam. I was able to use this new functionality quite effectively to eradicate all backlash on my X and Y axes.
Finally, I did some test code. The axes never stuck and my circles came out perfectly circular. I also figured out how to do complicated drawings using Inkscape and the laser cutter extension, so I had my machine do an amazing job of drawing its name (click the picture for a bigger view):
That engraving of the name "PiKnife" represents so much - the culmination of hours and hours of work. It means so a lot to me to finally have a beautiful piece of proof that this actually does stuff. I was truly amazed when I saw such fine, curving lines meeting up perfectly. I look forward to a lot of future use of this machine.
My next goals will be to add in the limit switches and look into the timing issues. However, neither of these affected the engraving above, so I am currently a very happy engineer.
Experiment 29: Lost Foam Casting a Slingshot
After seeing some cool videos on lost foam casting and also becoming addicted to Joerg Sprave's videos on YouTube, I decided that I had to try this method of metal casting. I used some StyroFoam as my foam material to carve into a slingshot and then put it in sand for casting. After pouring, it turned out quite well! It has a few pits and imperfections, but it looks pretty awesome otherwise. Although its rubber doesn't perform very well in the wintry cold, it should be powerful enough for squirrel hunting in the spring and summer. I look forward to blasting some stuff to tiny bits as soon as it warms up!
Also, check out its Instructable for more detailed information! If you want to watch the pour, check out this video and this ingot casting video on my YouTube channel. I have included a few pictures of the casting session (I also cast a few nice-looking ingots in the same session):
Also, check out its Instructable for more detailed information! If you want to watch the pour, check out this video and this ingot casting video on my YouTube channel. I have included a few pictures of the casting session (I also cast a few nice-looking ingots in the same session):
Laser Cutter Build Night: It Works!!!!
After many unproductive and dissatisfying hours of trying to modify the code I downloaded off of here, I finally gave up, realized that the code was never going to work with my setup, and began to completely rewrite two of the files I downloaded. If you look at the code, you will see that there are three files: Bipolar_Stepper_Motor_Class, Motor_control, and Gcode_executer. I totally rewrote the first two. Bascially, my code uses threaded programming in Python to make both axes move at the same time. This is what makes diagonal lines instead of just a bunch of "staircase" lines imitating a diagonal line (these happen if you only drive one motor at once). I will be posting my code very shortly; however, it isn't done yet, so I will wait on that.
Rewriting the code and testing it to debug it wasn't as hard as I thought. I found that typing up a document in a text editor outlining what my code would do helped a lot. It kept me on track and gave me some room to think about what the code actually had to do before jumping in. I only had a few bugs to fix - division by zero (added an if statement to catch that case) and syntax errors.
When I tried the code, I was amazed to see that it actually worked! It successfully drew the circle I told it to draw using G-code and even cut it at a reasonable pace instead of super-slowly! Elated by my long-awaited success, I drew a sort of ninja star in a box using Inkscape and then converted it to G-code using the instructions provided here. Amazingly, it worked! Mostly, that is. For some odd reason, the center circle of the ninja star and one of its arms were about an inch away from the real center of the ninja star. I theorize that this could have been because of one axis getting stuck, because when the program went to the home position, it actually stopped about an inch away from the limit switches (still have to code those in). What this means is that the code thought that the stepper was moving when in reality it wasn't; thus, when it told the motor to move x steps to go home, it didn't reach home because it the motor was farther from home than the software thought it was.
There are a few minor bugs to work out (besides fixing the sticking problem, or whatever else caused the ninja star misplacement). I noticed that my circles I cut had flattish parts on them along one axis of movement. I think that this is caused by the minor backlash issue I have - when one axis has reached the "vertex" of the circle along its axis of movement, it should turn around and start moving the other way. Backlash causes it to go straight for a few hundred steps as the motor is rotating in its backlash. Adding some simple code to detect change in direction should fix this.
Timing is another issue. It was probably the biggest issue with the ready-made code, and it is possibly still a minor issue with mine. Sometimes one axis will finish its movement to a point before the other finishes its movement to a point. Additionally, when doing very small, detailed movements, the laser seems to move more slowly than when it is doing a "line drive" by moving a large distance in one move command. I believe that this these issues are caused by minor mishaps in timing and tiny bits of lost time here and there in the thousands of start and stop movements required for fine detail. I'll have to see if I can alleviate this issue; it may not be entirely correctable.
Rewriting the code and testing it to debug it wasn't as hard as I thought. I found that typing up a document in a text editor outlining what my code would do helped a lot. It kept me on track and gave me some room to think about what the code actually had to do before jumping in. I only had a few bugs to fix - division by zero (added an if statement to catch that case) and syntax errors.
When I tried the code, I was amazed to see that it actually worked! It successfully drew the circle I told it to draw using G-code and even cut it at a reasonable pace instead of super-slowly! Elated by my long-awaited success, I drew a sort of ninja star in a box using Inkscape and then converted it to G-code using the instructions provided here. Amazingly, it worked! Mostly, that is. For some odd reason, the center circle of the ninja star and one of its arms were about an inch away from the real center of the ninja star. I theorize that this could have been because of one axis getting stuck, because when the program went to the home position, it actually stopped about an inch away from the limit switches (still have to code those in). What this means is that the code thought that the stepper was moving when in reality it wasn't; thus, when it told the motor to move x steps to go home, it didn't reach home because it the motor was farther from home than the software thought it was.
There are a few minor bugs to work out (besides fixing the sticking problem, or whatever else caused the ninja star misplacement). I noticed that my circles I cut had flattish parts on them along one axis of movement. I think that this is caused by the minor backlash issue I have - when one axis has reached the "vertex" of the circle along its axis of movement, it should turn around and start moving the other way. Backlash causes it to go straight for a few hundred steps as the motor is rotating in its backlash. Adding some simple code to detect change in direction should fix this.
Timing is another issue. It was probably the biggest issue with the ready-made code, and it is possibly still a minor issue with mine. Sometimes one axis will finish its movement to a point before the other finishes its movement to a point. Additionally, when doing very small, detailed movements, the laser seems to move more slowly than when it is doing a "line drive" by moving a large distance in one move command. I believe that this these issues are caused by minor mishaps in timing and tiny bits of lost time here and there in the thousands of start and stop movements required for fine detail. I'll have to see if I can alleviate this issue; it may not be entirely correctable.
Experiment 28: DIY scientific ampoules!
In the near future, I plan to make elemental iodine for my element collection. To effectively store iodine long-term, a hermetic (airtight, perfect) seal is recommended. Scientific glass ampoules then, are perfect for storing iodine for years and years, like in a periodic table display.
In this experiment I made two glass ampoules myself from miniature test tubes. I held the test tube by its bottom end with gloves and then torched the tube about 1cm from its mouth. A propane blowtorch works well for this purpose. I rotated the tube a few times to evenly distribute the heat in a band around the tube and in about 30 seconds, the tube softened. I then used pliers to pull the mouth of the tube away from the rest of the tube by a few centimeters. Then, I slowly removed the test tube from the flame, letting it gradually get cooler. The end result was absolutely spectacular given the easiness of the experiment:
When the tubes are filled with crystal iodine (I will pour it down the thin neck of the ampoule), I will hit the narrow neck of the ampoule with the hottest part of the torch flame to rapidly melt it without heating up the iodine. Then, I will use pliers to pull the neck of the ampoule completely off, thus sealing the iodine inside. I am quite pleased to have such an easy way of making ampoules for chemistry stuff!
In this experiment I made two glass ampoules myself from miniature test tubes. I held the test tube by its bottom end with gloves and then torched the tube about 1cm from its mouth. A propane blowtorch works well for this purpose. I rotated the tube a few times to evenly distribute the heat in a band around the tube and in about 30 seconds, the tube softened. I then used pliers to pull the mouth of the tube away from the rest of the tube by a few centimeters. Then, I slowly removed the test tube from the flame, letting it gradually get cooler. The end result was absolutely spectacular given the easiness of the experiment:
When the tubes are filled with crystal iodine (I will pour it down the thin neck of the ampoule), I will hit the narrow neck of the ampoule with the hottest part of the torch flame to rapidly melt it without heating up the iodine. Then, I will use pliers to pull the neck of the ampoule completely off, thus sealing the iodine inside. I am quite pleased to have such an easy way of making ampoules for chemistry stuff!
Experiment 27: Key Duplicating by Casting
I have always wanted to give key copying a go like the secret agents do in spy movies, so I tried it using my house key. Before you freak out and say that key copying is illegal, note that I used my house key, which I own. Do not copy other people's keys. That is probably illegal and could be a felony.
Anyhow, I used some creative methods to quickly copy the key and cast it in zinc. After a bit of touching up, the casting actually worked! Check out the Instructable for pictures and more information! Also, if you don't believe me, watch this video of the test in my door:
Anyhow, I used some creative methods to quickly copy the key and cast it in zinc. After a bit of touching up, the casting actually worked! Check out the Instructable for pictures and more information! Also, if you don't believe me, watch this video of the test in my door:
Update to YouTube Account Suspension
Bleh. YouTube has not contacted me once about why my account was suspended, nor have they given the ScienceWithScreens channel back. I am thouroughly disappointed with how they have handled this issue. It should have been corrected months ago, since I never did anything wrong.
What I find strange is that using my normal email address (which I used for the ScienceWithScreens channel) I am still able to get into YouTube, just not into my old channel. Odd. Apparently, YouTube doesn't hate me enough to completely ban me. :)
This means that I will be uploading more science videos to the new channel YouTube gave me under the same email, located at this address:
I am super happy, and I hope you are, too! Look forward to some really cool projects I have up my sleeve. I will also fix all those "broken" videos that now exist on my blog.
Laser Cutter Build Night: It's a Fixer-Upper...
So my grand plans of spending this coming Saturday laser cutting amazingly complex and smooth curves, swirls, text, and other shapes isn't exactly going to work out. The code I modified works, but it is a real fixer-upper. At first, after a few edits of syntax errors, it did technically move the stepper motors... I would have been dead and gone by the time it actually finished. I had to place a finger on the motor rotor to feel if it was spinning or not. It was simply too slow to even notice with the human eye.
After a bit more modification, I "successfully" cut some ovals into some paper using Inkscape and a laser engraving extension to generate gcode. The Python I modified did make ovals, they just didn't close off and looked more or less scribbled by a toddler. In addition, the extremes I had to go to to make it work made the movement extremely jittery, although not by the stepper's fault. I would have taken pictures but it is 11:14 PM and I'd better be off to bed sometime soon.
I will be working to try to salvage this code and if it doesn't work I suppose I will have to think something up. This is going to get interesting...
After a bit more modification, I "successfully" cut some ovals into some paper using Inkscape and a laser engraving extension to generate gcode. The Python I modified did make ovals, they just didn't close off and looked more or less scribbled by a toddler. In addition, the extremes I had to go to to make it work made the movement extremely jittery, although not by the stepper's fault. I would have taken pictures but it is 11:14 PM and I'd better be off to bed sometime soon.
I will be working to try to salvage this code and if it doesn't work I suppose I will have to think something up. This is going to get interesting...
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