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tamiya double gear box power supply

hi guys!! sorry for the noob question, but i need to know how to control the tamiya double gearbox with arduino but powered by external source. i mean, i have the motor connected to the arduino, but how can i give to the motor an external supply?


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I have arduino uno with motor shield. 

I have connected following peripherels to arduino board:

1. Motor shield

2. 2 DC motors

3. 1 Servo motor

4. 1 IR sensor.

My device is working properly when I am connecting it through USB. But, on providin 9V battery supply through motor shield, its not working.

Though LED is glowing on the motor shield board.

I have also connected the jumper on motor shield board.

Please suggest any solution for this.


Abhishek MIshra

The problem you are having is most likely your power source.  Are you using a battery like this? http://en.wikipedia.org/wiki/Nine-volt_battery  Those little 9 volt batteries can't provide enough power for motors.  They either won't work at all, or wont work for long.  If you read the links listed above, you will see that.  You will need a larger, more powerful battery to run your motors.  A battery pack of 4 to 8 rechargeable AA batteries should be an easy way to get started.

Thanks for your suggestion.

Yes I was using the same battery as on the link you mentioned (9 volt).

I have tried some more combination for batteries, but still got the proper result.

1. 3 AA batteries (not rechargeable)

       Result: Only servo was rotating, but not the other 2 motors.

2. 4 AA batteries (not rechargeable)

Result: Neither servo, nor other 2 motors were working.

But, whenever I connect from USB, it works perfectly. I hope through USB, I get a 5 volt supply.

So, I tried using 3 batteries of AA. Thus, providing a 4.5 V supply. But this also was only able to run the servo but not the motors. :(



Is there any reason you don't connect the 2nd power supply to the "2-pin terminal block and jumper to connect external power, for seperate logic/motor supplies."

What CtC said. Plus, there are some Arduino shields that include a motor driver and other features helpful for a robot.

Ro-Bot-X (an LMR member) created the Robot Builder's Shield

Adafruit has a Motor/Stepper/Servo Shield

Search around. There are others. Or you could try to build your own.

If the motor is currently connected directly to the Arduino, you have a problem. Your arduino is not capable of driving your motor directly, you should use a motor driver such as a L293D. This motor driver chip will allow a 2nd power supply to be used.


no i have the motor shield by adafruit. so if i connect the motor to the shield i can't use also a power external supply?

Do you see how it would have been helpful to know that you had the Adafruit motor shield from the very beginning?

We can only help you if you provide good information. We are not mind readers.

So now, instead of us guessing how you have things set up, please describe in good detail what equipment you have and how you have it set up. Pictures, diagrams, etc. would be helpful, but at a minimum you need to describe how everything is connected to everything else.

Your original post left a lot of information out.

thanks a lot. i've read the motor shield info and i've undestood where to add power supply on the shield. one thing: what kind of battery i have to use?:)

Two posts you may find helpful: