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.