DC Adapter for Arduino Motor Shield Problem

Dear all,

I have an Arduino UNO board with a motor shield board plugged on it. I have a step-by-step motor attached. It's a 2.5 V DC Motor from RS-Amidata. If I use an USB cable, 1.5 mts long, I can move it without any problem, and it's working properly. But I need to use a 15 mts usb cable, this is not sufficient to give power to move the motor. So I've attach a DC adapter with 6V 1000mA power, but when I attach it to the board, the motor is "clicking" continuously, as trying to move, trying to move without any order or signal, every second. When I send parameters to move, it do it correctly, but it's appearing to try to move continuously.

Anyone has the same problem? Now how to solve it?

Thanks a lot everybody.

Manuel

From the UNO product description page...

Input Voltage (recommended) 7-12V Input Voltage (limits) 6-20V

Your probably not getting enough power.

I did it with 12V, motor is working ok, but, while inactive, it's trying to move (or like it)... giving a noise like "click, click, click"...