How to power an Arduino Uno from a 36v4?

Complete beginner here, so please be patient with me!

I have an Elegoo Uno R3, and I want to use it to control a 24v 4A stepper motor via a Pololu 36v4 controller. This needs to form a self-contained, portable unit, so I can’t use a USB lead to power the Uno. I want to be able to connect to a (single) mains socket and not rely on batteries.

I already have a 240v AC to 24v DC 5A power supply adaptor, to drive the motor via the 36v4. My question is - how do I then take a lower voltage supply from the 36v4, with which to power the Uno?


BTW it’s for a rain sensor window closer, which will only draw on the motor for a few seconds at a time, and hopefully only a few times a week - though the Uno will need to be on for long periods of time, possibly 24/7, as it waits for a signal that it’s raining.


If you are open to switching to a different controller, our Arduino-compatible A-Star 32U4 Prime SV controller has an operating range from 5V to 36V, so you could just power it directly from your 24V supply. It also comes in a variety of versions, including one with microSD support, which might be useful for that kind of project if you want to collect data as well.

Otherwise, if you can specify whether you are referring to our Tic 36v4 USB Multi-Interface High-Power Stepper Motor Controller or our High-Power Stepper Motor Driver 36v4, I can offer some more specific suggestions for powering your Arduino.


Thanks Brandon.

I’ve just bought a Pololu High-Power Stepper Motor Driver 36v4. It was about $25 on Amazon UK so I am very keen to make it work!

Further info that may be useful:

The project is to make a self-contained, portable window auto-closer unit that can be plugged into the mains (UK 240v) where needed. The unit can be bolted onto the lower window frame and a rain sensor placed outside the open window. When this is activated, a pulley on the stepper motor shaft will spool in a wire attached to the bottom of the window, which is a top-hung Velux that sits flush on the roof of the house at about 45 degrees. The window will need to be opened manually first - this is just a device that we can leave overnight to shut the windows in case it rains.

In fact - thinking about it a bit more - I guess in some cases the unit will be left plugged in continuously for several days or even weeks at the height of summer.

The High-Power Motor Driver 36v4 does not have an onboard voltage regulator (aside from the one in the driver itself that can only source about 10mA, which isn’t enough). So, you will likely want to add a separate regulator to power your Arduino from the same power supply. We carry many step-down regulators that would work for this; for example, something like the D24V5F9 would probably be a good choice.


Thanks for the advice Brandon.

I bought some of these from Amazon UK, hooked one of them up, and everything seems to be working.