Controlling 8 servo motors

Hello, I am doing a robotic platform that is controlled by 8 servo motors. all motors should work with a synchronization because it’s a medical research and needs accuracy.

a strange behavior is happening, one of the servo motors move by itself or stop working completely, I was using a Mega Arduino and thought it was an issue in the processor, I changed it to an Arduino Due but the problem is still happening.

I am not sure also if the issue is because of the power, each motor require a 12 volts and 650 mA. I am connecting the motors in series.

I will also attach the code used.

sketch_aug02a.ino (1.38 KB)

I am connecting the motors in series.

?

Please post your code and a schematic.

The code is attached in the post.

The circuit is so simple I am connecting the 8 motors in series to a bread board and a common ground with the Arduino. The 8 signal pins are directly connected to the arduino

I am using a power supply that supplies 12 volts/ 4 ampere.

Please POST your code, and a schematic.

I am using a power supply that supplies 12 volts/ 4 ampere.

Do you understand what series means?