Hi Jaryd and Liam,
Thank you so much for your reply! That sounds good and is exactly the insight I was looking for. Thank you for the awesome project!
Best,
Maddy
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Hello, over in New York we’ve been building your amazing RPM design for student experiments. We’re finding that the rig works perfectly until it’s under load and then the servos start first to jitter and then just stop. As per the design spec we’re using the Raspberry Pi Pico 2 connected alternatively to the USB port on a laptop, to an external battery, and to a 5V USB wall charger. It doesn’t seem like the servos are being fried since they still work when not under load but maybe the system is not able to provide enough power for the servos when they are under load. (And from casual looking around, it seems like running more than 1 servo from a Raspberry Pi Pico is a known failure point.)
We’re looking into options such connecting the servos to an external power supply but wondering what advice you might have for us?
Thank you!
@Zoe315547 that does sound most likely like a power/current issue plus the servos being pushed a bit hard under load, rather than a Pico 2 problem on its own.
If the servos are being powered from the Pico’s 5V rail/USB path, I wouldn’t rely on that for two loaded servos. They can pull short current spikes when starting or changing direction, and that usually shows up as jitter, brownouts, or them just giving up under load. I’d power the servos from a separate regulated 5V supply rated for at least around 3A, and tie the grounds together with the Pico so the control signal still has a common reference.
One thing that can be used is something similar to Our Piicodev Servo Driver which can supply a decent amount of current so that brownouts are no longer an Issue. This is perfectly within bounds for the Pico 2 and isn’t too great a change to make to prevent issues like that.
