[Shakir] sent us this fairly easy way to do high speed photography. The idea is to use a microphone to detect a sharp sound on a surface and trigger the flash. The camera is set up with a long exposure to capture the action. Assuming your room is dark enough, you shouldn’t get much ghosting in your exposure. The circuit is a two stage amplifier that engages the flash using a silicon controlled rectifier. Be sure to check out the photos, some are pretty stunning.
[Alexander.m] shows us how to do a major overhaul on a cordless drill, replacing pretty much everything but the case. He needed some more power, but found the price tag of the bigger drills to be prohibitive. He opted for a more hacked together approach and used a 24 volt 1.4 hp hobby motor as a drive. He had to make a custom enclosure for the batteries too. The final result may not be the prettiest thing in the world, with that giant battery pack on the bottom, but it probably gets the job done pretty well and cost less than half of what a new one would have.
Disposable cameras are quite cheap, and include circuitry that produces very high voltages. Because of this, they have been harvested for many projects. We’ve seen them used for coil guns and large high voltage power supplies, even for fixing rechargeable batteries that won’t charge. The latest in the long list of uses is to create nixie tube drivers. [the_don125] shows us how to use a single disposable camera to power 2 to 3 medium sized Nixie tubes. Be careful, as we said before, this project deals with high voltage.
Cold Heat soldering irons are pretty cool. They heat up in seconds and cool down just as quickly. [photozz] shows us how we can make one from stuff we probably have sitting around right now. Cold Heat soldering irons work off of resistance, the tip material heats very quickly when electricity is passed through the two halves. Upon assessing what he had lying around, [photozz] realized that graphite would work much the same way. He modified a regular soldering iron with a new two piece graphite tip, and powered it with an old pc power supply. The end result is quite nice, though it still needs some kind of temperature control. You may recall seeing other electrical uses for graphite, such as making quick and dirty light.
[Justin] sent in his Digitally Assisted Billiards project. Using a web cam, a computer and a projector, these guys have set up a system that shows you the trajectories of your current shot. It detects the angle of the cue and displays a glowing blue line showing where each ball would go and where the collisions would be. It is a bit slow right now, and made somewhat less accurate by a low resolution web camera. This could be a fantastic teaching tool if it were to get some more polish. The source code is available on the site, so you could try this one out at home.
[Frits] sent us the SwiitBoard, an improvised version of the Wii balance board. He wanted to be able to do something a little higher impact than he could on the Wii balance board, and required more space to do it in too. Using two different kinds of foam and a piece of plywood, he put together the SwiitBoard. We’re not completely clear on how he is handling direction control. He states that it is derived from gforce.x. Can anyone clarify? Stay tuned after the break for a video of his demo software.
Continue reading “SwiitBoard: High Impact Wii Balance Board”
If you can get through the cell phone text speak, you’ll probably enjoy this cool tutorial on how to build a cell phone controlled robot. This bot decodes the key tones, similar to the automated phone systems we’ve all experienced. It uses a chip called a MT8870 DTMF decoder to translate the signal for the Atmega 16 controller. The circuit diagram is pretty hard to read, maybe we missed a downloadable one somewhere. The source code is available.
It would be nice to get some feedback from the robot, so you aren’t driving it completely blind. This is similar to the Lego cell phone rover that we showed you before. Next, he should make it recognize voice commands.
