I am working on a small DIY arm that uses 4 servos, specifically the mg996r servos. I am using a small buck converter since the servo only needs 4.8V-7.2V but I supply it with a 9V battery.
I tried connecting only 1 servo first with the buck converter and I ran with an issue but got resolve after connecting a common ground, then when I tried connecting another servo, only 1 servo is turning while the other doesn't. When I switch what pin they are connected to, the one that was working suddenly doesn't turn while the other one which was not working at first now works.
Test Code:
/* Sweep
by BARRAGAN <http://barraganstudio.com>
This example code is in the public domain.
modified 8 Nov 2013
by Scott Fitzgerald
http://www.arduino.cc/en/Tutorial/Sweep
*/
#include <Servo.h>
Servo myservo; // create servo object to control a servo
Servo myservo1;
// twelve servo objects can be created on most boards
int pos = 0; // variable to store the servo position
void setup() {
myservo.attach(12); // attaches the servo on pin 9 to the servo object
myservo.attach(13);
}
void loop() {
for (pos = 0; pos <= 180; pos += 1) { // goes from 0 degrees to 180 degrees
// in steps of 1 degree
myservo.write(pos); // tell servo to go to position in variable 'pos'
delay(15); // waits 15ms for the servo to reach the position
}
for (pos = 180; pos >= 0; pos -= 1) { // goes from 180 degrees to 0 degrees
myservo.write(pos); // tell servo to go to position in variable 'pos'
delay(15); // waits 15ms for the servo to reach the position
}
for (pos = 0; pos <= 180; pos += 1) { // goes from 0 degrees to 180 degrees
// in steps of 1 degree
myservo1.write(pos); // tell servo to go to position in variable 'pos'
delay(15); // waits 15ms for the servo to reach the position
}
for (pos = 180; pos >= 0; pos -= 1) { // goes from 180 degrees to 0 degrees
myservo1.write(pos); // tell servo to go to position in variable 'pos'
delay(15); // waits 15ms for the servo to reach the position
}
}
Simple Diagram:
