To control the movement of the gun, you will use two servo motors.
The "pan" servo controls the side-to-side (x-axis) movement of the gun.
The "tilt" servo controls the up-down (y-axis) movement of the gun.
Your third servo motor will be used to squeeze the trigger of your gun (if you are not using the electric trigger function).
TowerPro MG996 (left) if you are on a tight budget, otherwise the Hitec HS-805BB (right) is even better (but pricey).
Make sure you get "standard" type servos (180-degree rotation), not "continuous rotation" type servos.
In order to increase the torque and precision of your gun's movement, you can also add external gearing to your servos. Servocity.com sells some great metal gears that mount to the servo spline (toothed output shaft).
If you are ordering HiTec servos from ServoCity.com, then you get a Project Sentry Gun discount. Here's how to use it:
Next step: Base
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