Help Controlling NEMA 17 with Arduino UNO and A4988 Driver

I'm trying to control a NEMA 17 stepper motor with an Arduino UNO and A4998 stepper driver from Pololu. I have been trying to follow this tutorial:

Besides the NEMA 17, Arduino UNO, and A4998 stepper, I'm also using the following 12V 2A power supply:

However, I have been unsuccessful in getting any movement out of the stepper. One concern I have is that I blew the driver. I have heard that if you disconnect the driver and stepper at any point you risk ruining it.

Another issue I've noticed is that when everything is wired and green and orange indicator lights on my UNO seem to dim considerably if not go completely off.

My Questions:

  1. Is the driver ruined easily by disconnecting the stepper while the 12V power supply and UNO is powered?
  2. If the above is true what's the correct way to wire everything in order? Connect all but the power to the 12V supply and power to the UNO then do those last?
  3. Why are the indicator lights on the UNO getting dimmer? This doesn't seem normal and I'm wondering if it indicates I'm doing something wrong
  4. Any other tips or tricks to help in this process that isn't in the tutorial I'm using?

Thanks for the help!

  1. If you connect of disconnect a motor to the driver when motor power is applied to the driver the driver will almost certainly be destroyed. Connecting or disconnecting when the driver is powered down is OK.

  2. As far is I have seen it does not matter if you power the Uno or the stepper first. The thing is to never disconnect or connect the motor to the driver while the driver is powered.

  3. Something is wrong. Post a schematic and photos of your wiring.

  4. Pololu has a good page with lots of information on using the A4988. You must set the stepper coil current limit on the driver (Vref) properly before you use the stepper. Use the formula on the Pololu page to see what value to set Vref. You will need to know what value the sense resistors actually are on your board to plug into the calculation.

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