Arduino Micro + DRV8825 + 1.7A 2.8V Bipolar Stepper


My question is about required power supply on a project that I am putting together.

The goal is to drive the 1.7A, 2.8 Volt Bipolar stepper motor using the DRV8825 controlled by the Arduino micro controller (MC).

The MC needs 7-12V input and the DRV needs 8.2-45V, delivering 1.5A without the need to be cooled off.

The simple wiring diagram of the DRV8825 indicates that the controller and driver are powered separately. What I’d like to know is if I can use one source to power both of these. Someone had suggested that I would need a voltage regulator (D24V5F5). That is a little odd and I don’t quiet get what the advantage of the voltage regulator.

Since I will use my finished product in the dark somewhere outdoors I want to make it as simple as possible when it comes to batteries, so I am looking to power everything off one set of about 9 volt battery (pack).

Thanks for any guidance.


Motors and motor controllers introduce noise into the motor power supply, which can interfere with the operation of the microcontroller. It is certainly possible to use a single power supply for both but you may need an additional voltage regulator or noise reduction circuitry for the MC.

Battery packs won’t last long when delivering several amperes to the motor.


Thank you.

I know concepually abou noise (versus signal) in electronics but in this case I am not able to imagine it.

It seems the output of a voltage regulator is a (clean) steady and constant voltage. If the goal is to use a voltage regulator to power two boards, and if the output voltage out of the regulator was within range for either board, would one voltage regulator be sufficient to power both boards?

I will be driving the motor at smaller currents. During experimentation and programing the Arduino will be powered by my computer and the driver will have to be powered by an adaptor.

A final design probably will incorporate a motor with lower torqe than the one I have purchased. I purchaced the one with built-in screw because I didn’t want to deal with coupling and so on until I am good and ready.

Thanks again.


Theory is great, but voltage regulators are not perfect and are not capable of producing clean, noise free power under all circumstances. A motor driver involves rapid switching of large currents and those can lead to all sorts of electrical noise, some of which can be radiated by the motor and supply leads into other parts of the circuit.

There are also potential issues with inadequate output smoothing capacitors and lead inductance that can compound the problems, leading to L-C voltage spikes. For an eye-opener into these sorts of problems see this discussion:

Given these considerations, and that regulators are cheap, it is false economy to try to make do with just one. But you can certainly experiment to see what works in your particular circumstances. An oscilloscope is very handy for debugging an erratically behaving circuit.

Thank you for the information.

It turns out that the Arduino that I have bought already comes with a regulator. And I plan on using a voltage regulated power supply as well.

Since posting of this message originally, and based on your comment regarding amperage I changed the driver and the motor to lighter duty ones. I just received them today.