Make: Robot Build Contest – Final layout

I got some work done on my robot for the Make: Coasterbot contest, namely finalizing a design and thermo-shaping the CD for the body.  I say “thermo-shaping” trying to be fancy, but mostly it was a controlled melting of the CD while it was clamped to a straight edge.  This one isn’t *quite* square since I eyeballed the marks I used, so I may have to measure a little more carefully and make another one.

It’s beginning to look more and more like an old German tank from World War 2, so I think I’m going to call it PanzerBot, just for giggles.  I was originally going for a little more of a classic tank profile, but having only one sprocket per tread solves one of the design problems I was having, namely how to mount the rear sprocket securely, in proper alignment, and allow it to spin freely while still maintaining tension on the tread and not breaking free of the body.  Problem solved!

The batteries, four AA cells – actually two pairs, one pair for the motors and one pair, via a MintyBoost, for the Arduino – will go on the underside of the chassis thereby providing a low center of gravity.  Above the gearbox and motors I’ll put the Arduino MCU on standoffs, with a small sheet of copper between the board and the motors to attempt to minimize any EMF the motors might throw off.  Forward of the batteries, still on the underside of the chassis, will be the sensor suite.  I’m still working on the best setup for this.  Behind the batteries I’ll secure the MintyBoost, and above it, on the top side of the chassis I’ll put another small board with a power switch and a dual H-bridge circuit to drive the motors.  The sensors and the H-bridge are the two main concerns at this point.  I may, now that I think of it, just cave in and put a dual H-bridge chip in breadboard and save myself some soldering…

Anyway, that’s my progress so far.  I should have everything assembled some time this week so I can put up some pictures of how it will actually look.  The final dimensions are going to be around 5.5 inches wide, 5 inches long, and about 4 inches tall.  Hope you’re all enjoying it!  I know I am!