A Brain for Dolly

The "production" version of the Arduino shield stack used to run the camera dolly.

On the bottom of the stack is an Arduino Mega 2650. Then comes the hand-made card with five different circuits: a resistor ladder and socket for the controller's input buttons, the breakout and socket for the display harness, the OR-gate and resistor network for the limit switches, the opto-isolators for driving the camera via wired remote, and a little piezo beeper. Finally comes the Rugged stepper motor controller card.

12V input power drives the dolly via the green connector on the right (the stepper card helpfully feeds power to everything else). The little pot on the left side of the middle card controls the contrast on the display, whose harness plugs into the adjacent black header.

Everything is connectorized, due to lessons learned from the lightning trigger project - every switch, plug, etc. can be dismantled from it's associated board either by pulling a connector out or loosening a screw post. This came in handy when I got the first copy of the faceplate together and discovered it wouldn't fit in the box I'd bought - had everything not been connectorized, I'd have had to tediously de-solder everything, breaking the tested configuration and requiring it all to be tested again after it was reassembled on the new faceplate. (A trick I learned working on rockets. Don't ever say your defense procurement dollars are totally wasted.)