Making a servo tester using an Attiny85 micro chip, Attiny45 also works for this project. This diy servo tester is as good as ...

The Pico Serial Servo HAT, meanwhile, is a compact and efficient serial servo controller with two powering options, two serial servo connectors, and two programmable buttons for customization.

An Arduino is used to determine the servo’s current position versus the desired position, and it turns the motor accordingly with a BTS7960 motor driver.

He built a servo tester and demonstrator based on an Arduino, and went the extra mile to give it a good UI and a bunch of functionality.