I have a problem that i can't figure out. My knowlegde of electronics is minimal and with some internet searching i couldn't figure it out.
The situation: I have a stepper motor hooked up to a h-bridge and then to the arduino all powerd by an ATX.
The problem: When i power the stepper with 12V from the ATX, the motor starts to twitch. But when i power it with the USB from my computer it runs smoothly.
What did i do: powered the Vcc2 with +12V 8A and then with +5V 25A from the ATX, this made a twitch.
disconnected the ATX used a +9V 1,5A adapter on the arduino an connecting the Vcc2 to the +5V on the arduino, this did nothing.
Used USB powering, worked perfect.
Hardware: Arduino UNO ST - 235ATX SN754410 QUADRUPLE HALF-H DRIVER and this stepper http://www.eztronics.nl/webshop/catalog/product_info.php/cPath/41/products_id/368
If some one could help me out i would appreciate it. And if i didn't include enough info please tell.
p.s. moved the topic from troubleshooting to here