Powering the A-Star

Can the A-star board be powered through the 5 volt power output? I would like to incorporate the board into a system that already has a regulated 5 volt power line. I looked at the schematic (and read the section on power in the user’s guide)and honestly it looks okay, but I’m sort of an amateur. Thank you for the help!


Do you need to connect USB while it is in your system? If not, supplying 5V directly to the 5V pin on the A-Star should work. If you need to use USB, could you tell us more about your application? We might be able to suggest a solution. Connecting the A-Star to USB while supplying 5V to the 5V pin might damage things since it will bypass the power selection circuit.

- Jeremy


Thank you for the quick response!

I won’t need to have USB connected while the system is powered and I have a (Pololu) power switch between the batteries and 5 volt line. But that was one of my worries since I noticed in the schematic the power selection circuit between VIN and USB, so thank you for the warning.

I am replacing the microcontroller in a sumobot I built and it already has 5V regulated power line for microcontroller and IR line/object detectors. Basically, I wanted to upgrade and the A-Star is a perfect fit.

Thanks again,

Good luck on your project! It is exciting to hear that you are putting our new A-Star into a sumobot. Feel free to share about it in the Share Your Projects section of our forum.

- Jeremy

I would assume that the A-Star 32U4 can be powered via
the 5V output pin. But it definitely can be powered through the
USB connector port using a regulated power supply. SparkFun
has a neat little breakout board that makes it easy to do that.
It’s SparkFun product number is BOB-10031. My 32U4 only
needs 4.5 volts through the USB connector port.