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

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.