SG90 + Arduino pro mini 3.3V


In a robot I have 9v, 5v and 3.3V power sources. I'll be using a Arduino pro mini 3.3V to be able to communicate via I2C with a Raspberry PI.

I need to connect 2 servos SG90 to the arduino. SG90 are supposed to be 5V powered but I only have a 3.3V arduino... I can't find a complete datasheet for SG90...

Is there an issue connecting the servo like this:

Yellow: PWM from 3.3V arduino
red: 5V
brown: GND

Or should I connect like this:

Yellow: PWM from 3.3V arduino
red: 3.3V
brown: GND

Thx for your answers :slight_smile:

5V power with the signal at 3.3V should work with real SG90s. But there are so many fake SG90s around and they don't all behave the same way. All grounds needed to be connected.


What do I risk ? I just need to do some tests ? No risks to put some 5V on the Arduino... no ?

Power the servos separately using a 5-6V battery pack (NiMH or alkaline AA) and connect the grounds. There is no danger of 5V getting into the electronics via the servo control lead, as most servos (if not all) use capacitive coupling.