SparkFun Forums

[nccwarp9]

Hello to all on this forum, this is my first post here.

I have recently purchased my first Arduino and I wanted to test it out with a stepper motor.
So I also purchased EasyDriver and Mercury Stepper motor (ROB-09238).

I connected Stepper motor to EasyDriver in this order: Red, Green, Yellow, Blue.
EasyDriver is powered from Arduino 5V and 2 GND wires are soldered together and grounded next to 5V on Arduino.
To power the Stepper motor 12V rail of old PC ATX power supply is used. To much ??
Direction and Step are Pinout 3 and 4.

Ok, the problem.

When I connect Arduino to PC using USB Stepper motor starts to turn, sloooowly and this is before I turn on the 12v power to the motor. With 12v turned on, motor stops and doesn't react to commands. I tried to disconnect the step and direction and it still goes round and round sloowly but only if 12V is not turned on.

So I have Arduino + EasyDriver + Mercury Stepper with EasyDriver connected only to 5V and GRN on Arduino and stepper is turning. If power (Mercury is rated at 12V) is turned on it stops.

I have attached an picture of my current wiring. Please note that Green and Brown wires are not connected to Arduino but the stepper motor is still turning slowly.

IMG_1784.jpg

Any Ideas as to why this is happening?

Thanks

[EmbeddedMan]

A couple of things - the Easy Driver is powered entirely by the 12V motor power - there is no need to send any power from the Arduino. You should disconnect the 5V line from the Arduino to the Easy Driver.

12V is perfect for the motor and the Easy Driver. That should be no problem. You have the ground from the power supply connected to the Easy Driver, correct?

Make sure you have loaded a sketch that sets the Arduino pins 3 and 4 to be outputs. If they are inputs, then those two nets will be floating, and the Easy Driver will randomly step.

Also, make sure to power up the 12V to the Easy Driver before you power up the Arduino.

I'm really surprised that the motor moves without the 12V powering the Easy Driver. That shouldn't happen - I don't understand where enough power could be coming from to power the motor.

*Brian

[nccwarp9]

I believe that I have solved the issue.

The Mercury Stepper motor is connected to EasyDriver in this order: Green, Red, Blue, Yellow.