Hey everyone! I'm a newbie trying to wire up a 6x6 grid of actuating pistons that move about 9mm up and down. The setup involves 36 linear servos that I'm controlling through an ESP32 and three PCA9685 driver boards, each handling 12 servos. I'm using 2x 18650 lithium-ion batteries wired in parallel for power.
Here's my issue: the servos are jittering constantly, even when I'm not sending any movement commands from the ESP32. The jittering stops only if I disconnect the batteries. I suspect it's a power issue since the servos heat up a lot and have even warped the 3D-printed plate they're mounted on.
Currently, I'm connecting the batteries directly to the V+ input on the PCA9685 boards without any voltage regulators or capacitors. I'm not really sure what additional components I might need.
I have a few questions:
- Should I regulate the power somehow?
- Could this jittering be caused by voltage drops or spikes from the batteries?
- What would be a better power solution for my setup?
- Any debugging tips for power issues in a servo array?
I really appreciate any help you can offer! Thanks!
2 Answers
Definitely seems like a power issue. Each 18650 can deliver around 2-3 amps and considering you have a lot of servos, you could be right on the edge of power availability. The jitter may get worse as you add more servos due to that power limitation. If you suspect noise, trying some filter caps could help stabilize the power.
But just to be on the safe side, adding more batteries in parallel should give you a bit extra juice without burning out the servos as long as you keep within the voltage range they can handle.
It sounds like you might need to make sure that all your grounds are connected properly. If you're connecting the battery grounds separately from the ESP32 and PCA9685 boards, that can cause jitter. Try tying all the grounds together.
Also, if the servos are responding to the commands but just jittering, check how many servos you have connected at once. Start with just a couple and see if the jitter decreases as you add more. Your current batteries might be pushing close to their limits, especially with 36 motors drawing power, so consider whether your batteries are strong enough for the load. You might need to add more batteries in parallel if the servos heat up excessively!
So if I connect all grounds, will that solve the jitter? I’m just concerned about the power draw if I add more batteries.
Thanks for the insight! I wasn’t sure about adding batteries, but I guess it’s worth a shot to see if it helps.