allright. here this goes.
i try not to ask for help often but im kinda stumped.
i picked up a adafruit Motor shield v1.0 on amazon for a decent price and i finally got arround to trying it out. im using a tamiya duel motor gearbox with the motors swapped to 6v motors. i have a 8v 1a power pack plugged into ext_pwr on the shield and just loaded the motor test sketch from the adafruit example.
as the sketch has an output to M4 i connected one of my motors to M4 and the other left hanging for testing. i loaded the sketch and waited while watching the serial output. i can see that its running but my motor is not. i double checked the connections and everything looks ok but still no movement. i thought it may be an issue with the power pack so i disconnected my motors and connected a 12v 1a power supply for clean power.
i have pulled out my multimeter and checked M4.
if i probe red and black (shown below) i get 1.1mV
if i probe black and ground (below again) i get 11.91V
am i wrong to expect that i should get voltage on both screws of M4 instead of ground? i have changed the code to test M1 - M3 with the same result.
can somebody tell me what im doing wrong?
also if my Mshield is connected to my arduino UNO but not to ext-pwr im still getting voltage to GND and any M-screw. i was under the impression that the arduino powered itself and not the Mshield when the PWR jumper is not in.