Keyestudio 4DOF Manual page 128

www.keyestudio.com
// lower arm
void dabi()
{
if(y2>1000) // if push the left joystick upward
{
pos3=pos3-1;
myservo3.write(pos3); // the lower arm will stretch out
delay(5);
if(pos3<35) // limit the stretched angle
{
pos3=35;
}
}
if(y2<50) // if push the left joystick downward
{
pos3=pos3+1;
myservo3.write(pos3); // the lower arm will draw back
delay(5);
if(pos3>180)
{
pos3=180;
// limit the retracted angle
125