Firebot mechanical parts (3)

The nerf gun!

This is probably the best view to understand the operation of the gun – with the top shell removed.

The large area in the middle is shaped to allow a standard 6-shot nerf magazine to be inserted. Note the magazine release clip on the rear.

The servo with the arc-shaped actuator pushes the dart out of the magazine and into the flywheels at the front. Those are driven by standard RC brushless motors at 10K+ RPM. Once the pusher gets the dart between those, the dart is grabbed and accelerated out of the gun at silly speeds. We need to be careful to limit the speed so that the dart is below the half joule energy limit required to remain classed as a toy (see EN71).

The studs on the front of the gun unit are holes for mounting the Pi Camera to allow autonomous aiming.

The hexagonal axle connects to a servo mounted on the robot’s accessory point to control elevation of the gun. The robot itself will rotate to traverse the gun.

Here’s a video demonstrating the nerf gun in action.

I’m operating the pusher servo by hand (I don’t have it hooked up to the servo driver yet). You can hear the flywheels grinding down the dart tip(!), because I’m too slow to push it in, hopefully the servo will do it faster.

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