Romi 32U4 Wireless, Battery, and Arm Issues

I’ve recently got around to using the romi 32u4 for frc, but I seem to be having some problems.

When I try to connect to the romi wirelessly it always seems to be spotty as I get valid responses when I ping, but for some reason it doesn’t respond to inputs (it works through ethernet though).

Another problem that I have is the battery seems to be draining pretty fast. After putting in brand new batteries, it only takes five minutes and then the battery low sound plays. Is there any special battery that I should use?

The final problem that I have is regarding the arm. I currently have no idea which pins the wires for the arms go. Also I’ve seen the video for the arm (Pololu - Robot Arm Kit for Romi) and it looks like they have extra components on their romi (I’m referring to the red light), but I’m not sure what it is or if it is even important. If there’s any documentation on how to wire and use the arm, that would be helpful!

Thank you for reading all the way!

  • Hypers

Hello, Hypers.

It sounds like you are using the #4022 Romi Robot Kit for FIRST with the WPILib software. If so, please note that we are not involved with the software and Raspberry Pi side of the WPILib project, so you would need to contact the WPILib team for problems like the wireless connectivity (although it sounds like it could just be a poor WiFi signal).

As far as the batteries, I suspect the Raspberry Pi is a majority of the current draw, so you could look up ways to reduce the current requirements of the Raspberry Pi to see if any of them would be practical for your application. For example, you might try some of the suggestions in this write-up on optimizing Raspberry Pi power consumption. Additionally, if you are using Alkaline batteries, you might try switching to rechargable NiMH batteries instead.

The video you are referring to uses an RC receiver to control the servos for the robot arm. You can use the Romi 32U4 Control Board to control the servos in the Robot Arm Kit for Romi, but unfortunately, the on-board regulator cannot handle the additional current draw, so we recommend adding a separate external regulator, such as the D24V22F6, to power them. We do not have any specific examples for doing this, but you can find some details (and other considerations) in my post in this thread.


Hi Brandon,
Thank you so much for the help and the links!

  • Hypers
1 Like

Hypers, (Anyone), Could you take the time to post how you used the wiring connection for the 3 robot servos arms.
What pins on the 32U4. I trying to also figure out where the green wires go? Any help would be appreciated. Team 7454. Pics?



I have replied to your separate thread here, which I think answers most of your questions. However, to clarify about the servo wires, the green wire is optional and gives access directly to the servos position feedback potentiometer. If you want to use the feedback, you would need to connect it to a pin on the Romi 32U4 Control Board that is capable of reading analog signals, but it is not needed to use the servo normally.