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Topic: [beginner] how to choose the right power source (Read 618 times) previous topic - next topic

sebjapon

Hello everyone

I am trying to build my first robot with Arduino and the Motor Shield from Adafruit.

I am wondering something: is it okay to use power the shield with a 9V supply and use my 6V DC motor, or should I use a 6V supply for that?

Also: I have another motor that is only 3V this time. can i connect it directly to the Arduino board? What's the proper way to do that.

Thx for your help.


dc42

#1
Jan 10, 2012, 11:35 am Last Edit: Jan 10, 2012, 11:39 am by dc42 Reason: 1
That motor shield is based on the L293D which has a voltage drop of 2 to 3v. So you'll need a supply of around 9v anyway if you want 6v to reach the motors. Don't try to use a 9v alkaline battery though, they're not suitable for the sort of current needed by motors. Likewise, you'll need to feed 5v or 6v to the shield motor supply input to run the 3v motor.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

sebjapon

Okay. Thanks for your answer.

My 6V motor seems to work well. The 3V motor nearly burnt my L293D when I powered it with 9V.
So I guess I need different batteries for each motor. I have only a rechargeable 9V for now, I'll use it for the Arduino when I make the final project, and buy a proper pack for the motor.

dc42


The 3V motor nearly burnt my L293D when I powered it with 9V.


That's hardly surprising, when fully on the L293D will pass 6 or 7 volts to the motor. If the stall current of the 3v motor is low enough (say 0.5A or less), you could use +5v from the Arduino to power the motor shield when using the 3v motor.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

sebjapon

Yes. I tried that too. But then there is not enough power to move it. Thanks for the info.

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