A-Star board activates all servos when initializing

Hey. I’m making a robot using A-Star 32U4 board with a raspberry pi 4, and have been having a problem causing me really big issues.

For some reason, when I feed energy, starting the boards, all servos get triggered, forcing themselves and consequently consuming too much energy and burning the battery. This, without having been given any instruction at all.

When I turn it on, it works normally for about 2 minutes (with a baterry that haven’t been put to this stress yet) and them starts to make a noise (despite still working)

The sound:

Then the next fase was to make some weird movements:

And then it was only able to blink the leds from moment to moment, and nothing of the motor, becoming useless:

When I changed the battery, it went back to the first stage, so the problem is really on it (of course I didn’t let the other get burnt as well)

How do I make so it stop this behaviour? Because I have already lost a battery, only have one left and I’m on a big rush with this, more than one year of work, project, so if I lose this battery it’s the end of it. (But please don’t be afraid to suggest absolutely anything because of that)


Raspberry PI 4

A-Star 32U4 board

1300 mAh, 7.4v lipo battery (I charged it completely before connecting)

Thanks very much for whoever help. I really need some support.


I am not sure what servos you are using; could you post a link to where you got them or a datasheet? Could you also post a wiring diagram for your system?

Some servos will go to a default position when they are powered even when no signal is being sent to them. You can test if your servos behave this by uploading a program to your A-Star that does not do anything with the outputs to see what happens when you power the system.

Could you also tell me more about your batteries, including a link or additional specifications? Is it possible that your first battery just needs to be recharged, or is it showing definite signs of damage?

- Patrick