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I have bought two original TowerPro MG966R 360 degree continuos rotation Hi-torq digital servos.

Expected results :

  • 90 deg -- no rotation
  • 90 - 0 deg -- speeding up to one side
  • 90 - 180 deg -- speeding up to the other side

Real results :

  • When I am sending 50-90 degrees PWM, they behave like standard (non-continuos) servos and turn in 50-90 degree angle.
  • Bellow 50 there is small speedup, then continuos rotation at max speed to one side.
  • Above 90 there is continuos rotation at max speed to the other side.

I am using standard Arduino Servo library, servo has external 2A power and all grounds (servo, arduino, power) are connected together.

Both new servos behave same, so I assume fault is on my side (software). Same code and wiring works fine with other (cheap,copycat) servo I have.

May I ask for some pointer to what am I doing wrong?

Thanks

My test code :

    // 9 - servo pin
    // 2 - pot pin

#include <Servo.h>

Servo srv;

void setup(){
    srv.attach(9);
}
void loop(){
    //~ srv.write(map(analogRead(2),0,1023,50,90));
    srv.write(map(analogRead(2),0,1023,0,180));
    delay(10);
}

Bought here : ebay

Manufacturer page : here

Jirka Justra
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    there is no reason to use the map function or the analogRead function ... use minimal code when debugging – jsotola Oct 30 '20 at 18:57
  • What @jsotola said, and: you are updating the servo signal at a higher rate than its normal PWM frequency of 50Hz; anything could happen. Try a longer delay. – ocrdu Oct 30 '20 at 19:06
  • Ok, thanks for corrections .. I've tried simpler code and longer delays (20,50,2000) but it didn't help - same result. – Jirka Justra Oct 30 '20 at 19:17
  • Hm. Weird. Also weird: the Towerpro MG966R product video at the bottom of this page: http://www.towerpro.com.tw/product/mg995-robot-servo-360-180-rotation/ shows about the same behaviour you describe, but I can't imagine these servos in the video are "working as intended" if they are supposed to be continuous rotation servos. – ocrdu Oct 30 '20 at 20:10
  • I've contacted manufacturer and linked this question – Jirka Justra Oct 30 '20 at 20:39
  • looks like a soft start function of some kind – jsotola Oct 31 '20 at 00:43
  • @Jirka-Justra: Any answers yet from the manufacturer? – ocrdu Nov 02 '20 at 20:15
  • Guy e-mailed me 'I will get back to you' .. so I am currently on hold. – Jirka Justra Nov 02 '20 at 21:05
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    update : I've send kind reminder; response was that they arrange replacement for me .. hmm - interesting, but ok with me so far – Jirka Justra Nov 04 '20 at 02:37
  • update : I've got new set .. it rotate both side and continuously, but speed is constant :/ ... will communicate with them more - build quality is great as usual – Jirka Justra Dec 20 '20 at 15:31

0 Answers0