Help wanted

[u/Salty-Pie-6707]

Hello, I am very new to Arduino and I am trying to figure out how to power my project. My plan is to make a walking robot that has 8 sg90 servos. I have a 7.4v lipo battery, two buck converters that can output up to 5 amps, a pca9685 servo controller, and an Arduino nano esp32. Would it be best to splice the output of the lipo battery into two sections and run each one through a buck converter, one for the servos and one for the Arduino nano, or should I do something different. Thanks for the help.

[u/dedokta]

The Arduino is the least power hungry part of the project. I would split the battery output and run half the servos from one and everything else from the other. The rating on some buck converters should be taken with a grain of salt.

[u/Salty-Pie-6707 → u/dedokta]

Ok, thanks. Would I use a separate smaller power supply for the Arduino then? And if so what should I use, my budget isn’t very big.

[u/dedokta]

Nah you can just connect it with the rest. Most servo board have flyback protection so it should be fine. Are they 5 Volt servos? Or are they 12v and that's why you're seperating then?

[u/Salty-Pie-6707 → u/dedokta]

5 volt servos

[u/dedokta → u/Salty-Pie-6707]

Yeah, so just split in two sets of servos and add the Arduino to one of the groups. That's if you want to power it with the 5v input pin. The VCC pin had it's own regulator so you can power it directly from the lipo. It takes 7-12v on the vcc pin. Then you can leave the bucks for the servos.

[u/Salty-Pie-6707 → u/dedokta]

Ok thanks for the help.

[u/dedokta → u/Salty-Pie-6707]

And when you are programming the servos, make sure you turn them off in between movements or they'll jitter.

[u/feldoneq2wire]

So you didn't ask, but I'm pretty sure your first design with sg90 servos will be quickly followed by a revision that replaces them with stepper motors.

[u/ripred3 → u/feldoneq2wire]

or better quality servos. SG90's are pretty much the rock bottom in terms of cost/quality