When controlling a continuous rotation servo, the drive shaft should be completely stopped if the program has written the center point, ie. 90 degrees (correctly calibrated). I first noticed something was wrong while programming via GPIO, but even a reality check proves the issue exists:
#include <Servo.h>
Servo servo;
int positions[] = {0, 90, 99, 180};
int i = 0;
void setup() {
Serial.begin(9600); servo.attach(9);
}
void loop() {
int position = positions[i]; servo.write(position); Serial.println(position); i++; if (i == 4) { i = 0; } delay(2000);
}
When this is run, 0 spins full speed in one direction, 90 is a bit slower, 99 is stopped and 180 is full speed in the opposite direction. This should be stopped at 90.