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

Community General Discussions
1

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....

2

Rotating the motors manually

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

3

They are currently wired

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…