Building a robot - Day 1

So I got into robotics... again, last night. All of this came about from discussion I had with some fellow coworkers about how their kids were studying robotics in school using the Lego Mindstorms kits. All of this discussion got me thinking and so I decided to "scratch the itch" and document my successes and failures on here.

Last night I began working on the actual mechanical aspects of the robot. I have decided to keep it simple and to attempt to only use parts that I have sitting around (I have a lot of parts!) or that I can get for free (ie. I don't want to spend any money on this if I can avoid it).

After about an hour of thinking I came up with the following design; The chassis is a small plastic container that used to be a DLT tape case driven by 2 motors, one for each side driving the rear wheels. Rather than using two front wheels, the plan is to use a single caster wheel mounted in front. This should allow the robot to rotate a full 360 degrees on the same spot.

The robot will be remote controlled from my PC. The actual details behind the link have yet to be thought through, however, I do have a few thoughts in mind such as WiFi or Bluetooth (using a old discarded Pentium SBC I have laying around or by hacking a old 2ch RC I have. I figured I could "cross that bridge" when I get to it. At worst, I'll implement autonomous control using a microcontroller that can have instructions downloaded to it via a serial cable.

Rather than driving the wheels directly I decided to go with a small gear box on each wheel to help with the drive. Here in lies my first problem; Finding the right gears to attach to the axle and motor. It seems that of all the gears that I have (and I have a LOT), none of them match! - They are all of different ratios. I guess I'm just going to have to work out a way to mash various different gears to from the same ratio on either side. My other hop is to be able to scrounge for parts at my family and friends place. If anyone out there has an old VCR, DVD player or cassette deck that they don't need, please let me know.

For now, until I can find the right gears I went ahead and began working on the main body by drilling holes for the axle bearings, etc. - I hope to have some pictures up once my wife brings home our digital camera.