I don't know very much about Arduino, but from some basic research I have read that the Arduino Pro Mini can only support two servo motors.

I am trying to create a set of reaction wheels using hard drives, brushless motor controllers and an Arduino Pro Mini. (I can get a different model of Arduino, but that's what I had lying around.)

Since a set of reaction wheels requires a minimum of three hard drives to work, I need to find a way to be able to control another servo using my Mini.

Is it possible to control more than two servos (with precision) when using an Arduino Pro Mini?

If so, how?

If not, should I look into a different model of Arduino? Since I value small size, will an Arduino Micro work?

  • \$\begingroup\$ Where did you read that Arduino Pro Mini can only support two servo motors? Could you add a link, please? \$\endgroup\$ Commented Dec 22, 2014 at 4:03
  • \$\begingroup\$ @NickAlexeev I don't remember. I can go through my search history and try to find it if it helps. If that's not true, then how many can it support? \$\endgroup\$
    – CoilKid
    Commented Dec 22, 2014 at 4:06
  • \$\begingroup\$ @NickAlexeev *How many can it support without added shields or breadboards? \$\endgroup\$
    – CoilKid
    Commented Dec 22, 2014 at 4:07
  • \$\begingroup\$ @NickAlexeev older versions of the Servo library for Arduino only worked on pins 9 and 10 (iirc). Newer versions have removed that restriction. The Pro Mini has 6 PWM pins, and should be able to handle that many servos. \$\endgroup\$
    – kolosy
    Commented Dec 22, 2014 at 5:17

1 Answer 1


That's not correct. There was a limit in early versions of the Servo library, but that's been removed. The Pro Mini uses the same ATMega 328p chip as a full-size arduino, so the only limitation is the number of PWM pins that are broken out. There are 6 on a Pro Mini, and the library supports up to 12 on a non-mega.

Also - note that the arduino micro is based on the ATmega32u4 chip, which means it'll behave like a Leonardo, not a standard Uno. It has 7 PWM pins.


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