my Adafruit motorshield is getting current from Arduino board even after disconnected from battery. I was planning to give separate dc power from 6 AA cells to motor shield but not sure if extra current will enter into Arduino and damage it. I have Ultrasonic sensor connected to motorshield which is getting +5v from board (may be Arduino).

Please suggest how to solve this problem.



If all else fails, read The Manual

The manual indicates that it is intended that the MS electronics may be operated by the Arduino power supply while using a separate external supply for the motor.

Pages 37 to 39 explain about powering options.
The Arduino and the shield interconnect all of : 3V, 5V, Vin.
3V may not be used by the shield.

Arduino Vin to MS V+ is broken by jumper "PWRJMP" - purple rectangle in diagram below.
Arduino 5V to MS Vcc is not interrupted by a jumper - See labels in red squares below.

enter image description here

You did not say what version shield you had or which Arduino or what you mean by "disconnected from battery" or supply any links to relevant documents. ALL of these things will help people to help you better.

Assuming latest MS version,

adafruit motor shield v1.2 - discontinued.

github v1.2 schematic this appears to be pre V2 BUT is linked to from a ference in the V2 manual so is probably "more or less correct".

adafruit motor shield v2 manual - probably what you have

adafruit current MS page

This probably tells you what you need to know. Manual page 37-38

  • How to set up the Arduino + Shield for powering motors

    Servos are powered off of the same regulated 5V that the Arduino uses. This is OK for the small hobby servos suggested. If you want something beefier, cut the trace going to + on the servo connectors and wire up your own 5-6V supply!

    The DC motors are powered off of a 'high voltage supply' and NOT the regulated 5V.
    Don't connect the motor power supply to the 5V line. This is a very very very bad idea unless you are sure you know what you're doing!

    There are two places you can get your motor 'high voltage supply' from. One is the DC jack on the Arduino board and the other is the 2-terminal block on the shield that is labeled EXT_PWR. The DC Jack on the Arduino has a protection diode so you won't be able to mess things up too bad if you plug in the wrong kind of power. However the EXT_PWR terminals on the shield do not have a protection diode (for a fairly good reason). Be utterly careful not to plug it in backwards or you will destroy the motor shield and/or your Arduino!

  • I am using Adafruit motor shield V 1.0 and Arduino UNO which comes with starter kit. When I say disconnected means that I am supplying 9v from 6 AA cells to motor shield on power terminals 'EXT_PWR' and removed the power jumper on motor shield. But as defined here it is still getting +5v from Arduino and its green LED is lit. – Builder Feb 19 '15 at 16:18
  • @qazifarhan We are slowly getting there. The extra information is useful. All the information will be even more so |1. Please post links to documents describing what you say you have. If you do not have them then having you locate them makes more sense than expecting someone else to dos so. IF you can't find then then others will no doubt help. | 2. Read the material I posted and the manual. What it says sounds very likely to be completely applicable to what you have. | 3. Then ask again if still uncertain – Russell McMahon Feb 20 '15 at 5:37
  • @qazifarhan Here is the circuit diagram for V1.0 I suggest you add a link to it in your question. The advice I offered re V2 also applies to this. Here is the V1.2 shield page that lists the V1.0 diagram - I suggest you add it to your question. – Russell McMahon Feb 20 '15 at 5:46

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