Keyestudio 4DOF Manual page 237

myservo3.write(pos3);
delay(5);
if(pos3<35) // limit the retracted angle
{
pos3=35;
}
}
}
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Test Result:
Stack the shield onto UNO R3 and upload the code. Powered on and connected the PS2 Joypad, you can use the
PS2 Joypad to control the robot arm actions.
// the lower arm will draw back
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