I have servo (TowerPro sg90) connected to 32 servo controller (this one) through UART interface (RX-TX, GND-GND). Seller provide documentation how to connect and control my servos, but it isn't work.

Servo work if I connect it indirectly to Arduino. Controller indicate that it is working too (photo below - red led).

I already try different servos. Also try use provided software to control servos from pc through Mac/PC. But it's interface is unreadable for me. I tried different options but servos not responding.

Sketch code below (from sellers examples):

void setup() {

void loop() {

Photo of my connections:


Sorry if it post duplicate some, but I cannot google this problem.

  • Just as additional information. If there is a PS2 controller attached to the board, then the serial port seems turned off. Dec 3, 2017 at 18:35

1 Answer 1


There is one connection missing - the one that powers the servo and board.

At the moment your servo board is getting a small amount of power through the RX pin - disconnect it immediately, you are damaging it.

You need to provide +5V to the +5V terminal block, and also a suitable voltage (+5V should do) to the VCC on the terminal block.

  • Thank you very much. I will try and accept your answer as soon as possible. Can you provide some reference where I can read about it? Because I cannot figure it out by provided docs.
    – rkyr
    Nov 30, 2015 at 19:38
  • @rkyr The reference is simply that the servo and board need power (all servos and boards need power) yet you have not provided any. No docs are needed for that - it's just basic knowledge.
    – Majenko
    Nov 30, 2015 at 19:39

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.