Servos are incredibly handy devices, offering precise rotational positioning when connected to a pulse-width modulation (PWM) pin on an Arduino. They're at the heart of most robotics projects, including the pocket-friendly MeArm from our friend Ben Gray, and while we've torn one down for educational purposes and taught people how to use them we've never looked at how to handle testing or calibrating large quantities of servos. YouTube user PinPointECE has handily stepped in with a video detailing a servo motor tester that is perfect for just that job. Based on an Arduino Uno with cheap LCD display, the project works even when disconnected from a PC and provides a read-out of the position setting - adjusted by a potentiometer - for quick calibration or testing of a servo through its full range.
If you have ever used the Servo Knob example sketch on the Arduino, then this project should be familiar to you. It is the exact same sketch, except the data will be displayed on our LCD instead. Having this data displayed as a standalone project is useful for many things: you can use it to determine the position of a servo and the direction and speed of a continuous servo without having to build the Servo Knob circuit each and every time.