I had succeeded in controlling 3 12v solenoids via Max/msp sending serial to the arduino.
I was using 2 9v batteries in series and an irf520 mosfet along with a diode for each switch.
So basically everything went fine until I removed my third solenoid and tried to replace it with another solenoid (exact same type) with much longer wires on it. I wanted to
test if this was possible and if it didn't take too much current.
As soon as I plugged the first wire into my battery positive side, my whole system went down including my macbook rebooting.
When I had it back on, everything appeared to be fine (arduino internal LED's lighting normally), but I couldn't get even my old setup without the long wires to work.
So I tried uploading the sketch again (to see if the data had somehow been erased in the shutdown), but when trying this, the arduino IDE just tells me:
avrdude: stk500_recv(): programmer is not responding
and the usual blinking-when-uploading is not there. So I guess I fried the chip, no?
I have no living idea how this could happen.. I mean, everything worked before and I didn't apply any more voltage to the circuit. Could the resistance of the long wires be enough to kill the circuit somehow? The wires are aprox 2 meters each.
I've attached two pictures of the circuit, and hope it's possible to make some sense out of it.
I could write a schematic if it would be easier.
Basically all I did was to follow the pictures in the bottom of this link http://www.thebox.myzen.co.uk/Tutorial/Power_Supplies.html
and then just doing the same thing 3 times with arduino digital out pins 9, 10 and 11.
Any kind of clue would be very much appreciated. I'm not the biggest electronic-wiz, sorry.