Automated Self-Firing Ping-Pong Cannon

Designed by:
Ken McVettie
Joseph Heremans


What It Does
The automated self-firing ping-pong ball cannon is an automated cannon that scans a given battle field for a possible target, detects a target, calculates the angle needed to hit that target, and finally, fires upon that target. There is also a manual mode which allows the user to input an elevation angle, an azimuth angle, and fire the cannon manually.

Interface
Input
Infrared Detector: The infrared detector was implemented through the Analog to Digital Converter which translated voltages into distances relative to how close something is to the infrared detector.

Outputs
Servo Motors: The servo motors were controlled using Pulse Width Modulation (PWM). Pulse Width Modulation devices are dependant on how long the pulse is that is sent. In the instance of the servos, a pulse of 1.5 ms would center the servo, while a pulse of 0.9 ms would turn the servo one way, and a pulse of 2.1 ms would turn the servo the opposite direction. These pulses are refreshed every 20 ms (50Hz).

Valve Solenoid: The valve solenoid controlled the air flow in the air cannon which essentially acted like a trigger. This was controlled by a relay switch which was connected to the processor board. A 0xFFFF would be written to the trigger to start the fire and a 0x0000 would be written to close the firing valve solenoid.

Difficulties
We have trouble calibrating the cannon due to the lack of power generated by the air pump. The cannon essentially fired in the same place regardless of the cannon's angle. This was the most difficult project since we had to work around this, and never quite got the tuning correct. To fix this project we would need to replace our air pressure generation unit.


Pictures/Movies:
Picture 1
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Movie 1