Let's Make Robots!

Punchable/stompable switch

Hi, guys. I remember reading somewhere (maybe LMR, maybe Make Magazine?) about a DIY way to make a sort of electrical switch that closed a circuit when it was punched or stomped. It had something to do with a layer of foam between two contacts -- maybe the foam was partially conductive or something? I'm working on a musical project that involves recreating something similar to a DDR dance pad, and I'm trying to figure out how to make the pads. Does anyone know what I'm talking about, and maybe have a link or something? Or does anyone have any ideas that might prove useful? Thanks.

Robot that reassembles itself after being kicked

A pretty interesting video, if a little slow. It certainly inspires me to experiment with this sort of thing myself.

I gotta say though, the last five seconds or so are my favorite part :)

Dan

Mechanical spider vehicle

This thing is awesome. It must have taken a hell of a long time to design and build, and then you've got to have a garage to store it in :) But I kind of want to make one anyways.

Dan

Promising things on the horizon for LetsMakeRobots.com

Hey guys. I just wanted to give you an update on the upcoming changes we've got planned for the site. A month or two ago, after being frustrated at how limited our access to LMR's webserver was, I messaged Frits and offered to host the website on my own server. That way we would have the access to develop all the kinds of things we have in mind to continue improving the site and implementing all the great ideas we get.

Thinking of buying a mill

Hey guys. It seems like I keep running into projects where I find myself thinking, "man, a mill would make this step a lot easier" or thinking of a part or bracket that could be useful to be able to make. It seems like a mill is one of the more universally useful tools, so I'm considering investing in one. But I don't know much about them, and I was hoping someone here could provide some input. I remember someone here mentioning they were a machinist.

Cheapest way to communicate between microcontroller and computer

I'm working on a non-robotics project, an 'intelligent' mood light. I got a bright 3W RGB LED and soldered up a board so that I can control it from my Arduino (never worked with this much current before -- I got to play with 1W and 2W resistors). I found a nice lamp-type metal-and-glass housing and cut some sheets out of white plastic to sit behind the glass and act as diffusers. So anyway, I've got that all working, and I can cycle smoothly through colors, and it looks really pretty. But now I want it to do something more intelligent.

What sensor for detecting (and locating) people?

One thing I often want to do in a robot is have it be able to find (and maybe follow around) people. But I haven't been able to track down what type of sensor would be good for that. I've seen PIR sensors which detect motion, but they seem to be more for things like alarm systems, where they tell you that "something" is moving in their field of view, but you can't really use them to actually find which direction the motion is coming from.

Controlling a motor with an NPN transistor

Apparently I don't yet fully understand transistors, so I'm hoping someone can explain what I'm missing. I'm using USB 5V to power my MCU (an Arduino), and I've got a 9V battery pack (6x AA) for my motors. I'm trying to switch that 9V off and on for a motor. I don't need to change directions or control speed, I just need to be able to give it either 0V or 9V.