Change of plans... sorta..

Over the Mother's Day weekend/Fishing Opener, I had a second to take a rubber O-ring I got from the hardware store and try it out on the main drive pulleys and decided I didn't like it. Inconsistent and a little sloppy. So I really started to lean towards 6 small motors to drive this thing. I did a bunch of research the other day and found a bunch of motors with, at best, a 900 mAh draw all the way up to 4 Amps. That was never going to work. The Arduino motor controller has 4 motor connections with a 1.2 Amp limit on each. Since I have 6 motors, I'll need to double up motors on 2 of the motor connections which means, by my figuring, I'd need to find motors with at most 600 mAh.

 I happened to have a Zip Zap truck laying around so I stole the motor from that and tested it. It only had a 140 mAh draw! I remembered seeing similar motors in the micro helicopter section at the local hobby store so I made a run there after school yesterday. They were nice enough to let me test the only motor they had in stock and it came up around 140 mAhs too! So I bought the one and ordered 5 more. They should be in by the middle of next week. Here's a pic of the one I have:

So with something to measure now, I sat down and added to my CAD drawing. 

  I also found the limits to my computer after having more than one purple gear on the screen at a time so I changed the others to a smooth disc so I could still rotate the drawing. So now I need to draw in the brackets that hold the motors in place but you get the idea. Also, maybe some day I'll draw better wheels. 

  Here's a roughed out finished designed so folks can see what I have planned. The camera and rock sampling arm are by no means done. Just a quick addition to the drawing so you get an idea.

  So that's it so far. I'll get some time this weekend to actually work on it so we'll see how far I get without the other motors. 

  If only I had a laser cutter and a 3D printer! This would be so much closer to being done!