Motor shield is still drawing motor power from arduino even with external power connected

by **allanonmage** » Mon Dec 24, 2012 3:57 pm

I've got an Arduino Mega ADK and the Adafruit motor shield.

I have this board:
http://www.ladyada.net/make/mshield/
and this arduino:
http://arduino.cc/en/Main/ArduinoBoardADK

It seems that motors are being powered by the arduino even though I have turned off the external power supply, as they still attempt to move. I'm using code from here:
http://www.instructables.com/id/Intro-a ... oull-need/

For this first test, I am powering the arduino off of USB. I notice that the LED is lit as soon as USB is powering the arduino, or when I apply voltage from the external power supply (the roomba's battery to a voltage converter). I have the power jumper hanging on one of the pins, so it's disconnected and the motors should be drawing power from only the external power, right?

I bought the motor controller on amazon, and it came assembled. I am testing it out for the first time.

The motors sing a little, and it kinda sounds like one of them might not be moving. The arm worked fine even after I made a mount and whatnot for it.

The power supply is 5V 2A. I didn't realize I'd need a higher voltage b/c of the voltage drop on the H bridges to get 5V to the motors until i read a post here. I don't know if I have a supply in that range, but I'll look when I get home. Is 3.8V too close to the lower limit for this stuff?

by **adafruit_support_bill** » Mon Dec 24, 2012 5:07 pm

If you bought the shield on amazon, it is not an Adafruit shield. You should contact the seller for technical support.

by **allanonmage** » Mon Dec 24, 2012 5:51 pm

adafruit_support wrote:If you bought the shield on amazon, it is not an Adafruit shield. You should contact the seller for technical support.

Hey thanks for the quick reply. This is only the second motor controller I've bought, so maybe you can help me identify it and point me in the right direction for the manufacturer. I've uploaded some pics to help identify it. My phone is a little old, so the pics may not be that great.

Project:

The whole album:

https://www.facebook.com/media/set/?set=a.10151351037400498.519898.720010497&type=1&l=6e6e410d9c

by **allanonmage** » Mon Dec 24, 2012 11:56 pm

by **allanonmage** » Tue Dec 25, 2012 12:03 am

Seems I can't link directly to the images on facebook because the random gibberish names are banned words. :-/ I can't make this stuff up.

http://preview.tinyurl.com/c5jcfx4

http://preview.tinyurl.com/cpz36cn

http://preview.tinyurl.com/bmqjgs9

Motor shield is still drawing motor power from arduino even with external power connected

Motor shield is still drawing motor power from arduino even with external power connected

Re: Motor shield is still drawing motor power from arduino even with external power connected

Re: Motor shield is still drawing motor power from arduino even with external power connected

Re: Motor shield is still drawing motor power from arduino even with external power connected

Re: Motor shield is still drawing motor power from arduino even with external power connected

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