I'm using a motor shield with the arduino uno. But when I connect both the positive and negative end of my external power supply, the arduino disconnects from my computer, and I can no longer send commands to it. Does anyone know how to fix this please? The power supply isn't even on when I do this. There is no difference when I do turn it on also. I'm using the motor shield to control a stepper motor.
Now it works without the external power supply. I guess the motor shield doesn't require a power supply to run a stepper??
ngs078888:
Now it works without the external power supply. I guess the motor shield doesn't require a power supply to run a stepper??
Depends on voltage & current requirements of your motor.
(FYI - From the product page)
Power
The Arduino Motor Shield must be powered only by an external power supply. Because the L298 IC mounted on the shield has two separate power connections, one for the logic and one for the motor supply driver. The required motor current often exceeds the maximum USB current rating.
External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery. The adapter can be connected by plugging a 2.1mm center-positive plug into the Arduino's board power jack on which the motor shield is mounted or by connecting the wires that lead the power supply to the Vin and GND screw terminals, taking care to respect the polarities.
To avoid possible damage to the Arduino board on which the shield is mounted, we reccomend using an external power supply that provides a voltage between 7 and 12V. If your motor require more than 9V we recommend that you separate the power lines of the shield and the Arduino board on which the shield is mounted. This is possible by cutting the "Vin Connect" jumper placed on the back side of the shield. The absolute limit for the Vin at the screw terminals is 18V.