I said we could build something fun on a Saturday afternoon using stuff I already had sitting around. Cost: zero. My fee: pizza for lunch.
I have more robotics stuff sitting around than most normal people, but since the components we used are readily available I thought a more detailed build account was in order.
This is the basic electronic "guts" of the project, and requires a little explanation for the novice. To effectively control motors you need forward and reverse, and need the ability to go fast and slow. Basically you need what are called electronic speed controllers. The two black square objects are IFI Victor 884 controllers. The are durable, easy to use and can handle 12 volts of juice. You also need a radio receiver to tell the controllers what to do. Any RC radio receiver would in theory work. But I have taken to using a slightly more complicated system, the Vex controller. The yellow object is the actual radio receiver. The larger grey object is a microprocessor. I'll be honest, I mostly use these because I got a couple for free. But they are useful enough that I seek them out on ebay. Both the Victors and the Vex equipment come up fairly often and at a reasonable price, because they are used respectively by the very excellent FIRST and VEX robotics programs. After their competitions are over the robots often are scrapped and sold off. The Vex microprocessor also has the ability to accept programming if you intend to build a robot that is actually semi autonomous. What I am building here is basically a jazzed up, over sized RC car with a few extra features.
A high powered water squirter. This is a windshield wiper pump powered off the 12 volt main power. The water reservoir is a plastic mayonnaise jar. I drilled a hole in the lid so that we did not have an open container. Water sloshed onto electronics is bad juju. The bendy metal strip supports the water reservoir (held on by rubber bands), and allows the water nozzle to be aimed. I suggested that spraying people with water at crotch level would have the most attention getting effect. Other switches operated strobe lights and a siren.
Here is the final product, a robotic remote control fire engine. Built with a half dozen grade schoolers in four hours.
|range was about 15 feet|
I thought it was a pretty fun project, and the kid who presented it at the county fair won some nice ribbons for it.
I enjoy this sort of thing, so if any questions on projects like this drop me a line in the comments section.