“When I buy a new servo motor, I want to quickly check if it is working. The Two-Mode Servo Tester lets me do that in a minute. Servos, at least the cheaper ones I know, sometimes do not work as expected when they arrive: The gears jump, the electronic in the servo does not work or it is a 120 degree and not a 180 degree servo. It is a good thing to test a servo. Until now, I used to grab a breadboard, an Arduino, a 5V power supply, a USB cable, my PC and some jumper cables and built a servo tester every time from scratch. The Two-Mode Servo Tester is all that and more in a case.
There are commercial servo tester available for about $10, more or less the costs for this project. The products I found on Amazon test up to three servos in parallel and have three test modes: Manual, Auto and Neutral.
The Two-Mode Servo Tester lets you test up to four servo motors in parallel and has two modes: Follow and Sweep. In Follow, the connected servos follow the position of the potentiometer, in Sweep, the potentiometer is used to set the speed. Inside is an Arduino Nano and a Step-Up DC-DC converter to power the Arduino from the 5V power input. The device has a toggle switch to select the mode and a potentiometer to adjust the control signal.
To build this device, you will need to do some soldering. It is always surprising how these fragile electronic components survive my “soldering”. To program the Arduino Nano you need a USB Mini cable. The case is 3D printed with the two STL files that are attached.
It is cheaper to buy a servo tester. But on the images and videos I found, always Micro and never Standard Servos are used. The Auto mode seems not to have an adjustable speed. The Two-Mode Servo Tester has enough power to control four Standard Servos. It can be reprogrammed and you can give the switch and potentiometer another meaning if you like.
Supplies:{Description; Quantity}
- Arduino Nano; 1
- Step-up DC-DC converter, adjusted to 5V to 12V (aka. DC-DC Booster); 1
- 3-pin On-Off toggle switch; 1
- 100-1M potentiometer (aka. adjustable resistor); 1
- 100n capacitor; 1
- 10k resistor; 1
- 2-pin plug-in terminal block; 1
- Prototyping board 45x35 mm; 2
- 13-pin single row male header; 1
- 15-pin single row male header; 1
- 2-pin single row male header with 15mm long pins; 1
- 3-pin single row male header; 3
- 3-pin single row male header with two 15mm long pins; 1
- 2-pin single row female header; 2
- Tmst-Case Bottom, 3D printed; 1
- Tmst-Case Top, 3D printed;1”