Let's Make Robots!

Pushing power into a motorshield and arduino, via the motors!

OOPS!

ive been fiddling with my polargraph, which unless it is being programmed by USB, or run over a 9V wall wart remains unplugged. (The 9V wall wart can supply 1.6A, so i have it plugged into the arduino jack, and am using the "power take off" jumper on the motorshield.)

anyway, while pulling my gondla down (which spins the stepper motors) i noticed the motorshield power light, and both arduino lights started flickering, i think the duino started booting up!

obviosuly it only spins for a second or two, and i dont THINK it shines as bright as it does under proper power.

Am i likely to knacker either the arduino or the motorshield do we reckon?

I think i had better add on a "joystick" to the board, to allow me to move the gondla using the electronics, rather than maually....

 

in other news, It is coming along nicely. I now need to find a nice 15 px x 15 px image to render! Grayscale probably sensible to start with, but i dont see why i couldnt run it three times, each with an R, Y and B pen in the machine....

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Rotating the motors manually means that they will generate power - usually less efficiently than they use it.  Always a good idea to disconnect the motors when moving the motors as the power can harm the electronics, either with a high voltage spike or reverse polarity.  Hopefully you got away with it but you can definately harm electronics in this manner

OllyR's picture

They are currently wired into screw terminals, so disconnecting them would be a pain in the bum. I think a good way of switching them, would be to give each wire a relay (physical switch rather than a semi conductor) and then connect all the relay magnet pins to a 5v out on the motor shield. This way there is only a physical connection when the shield is powered. Or is there a better way i havent thought of....