Projects: Catapult Fridge

During my first tenure in Louisville working for GE, I kept myself busy and mentally engaged by experimenting with an Arduino Duemilanove, and eventually using it to control a fridge that launches canned drinks across the room to me. I was initially exposed to this project in January of 2010, and soon after drew up a mock design in Solidworks. At that point it was just a project for sometime far off in the future, but once I became comfortable with the programming language and Arduino interface, I realized that the project was much closer to becoming a reality.

The pictures seen here include the third and fourth overall design iterations, and are the product of many long hours. The can ‘dispenser’ as i call it is in its second iteration. Originally it was shaped like a capitol ‘L’ and only held 6 cans, but the current zig zag design (pictured inside of the mini refrigerator) is able to hold twelve cans. The cans are restrained from flowing out of the bottom by a wooden lever and two clothespins. When the elevator is fully descended, it depresses the clothespins, and the lever allows one can to roll out, and restrains the rest of the cans.

The elevator, (pictured above) the structure that travels vertically in and out of the fridge cavity is the assembly that has kept its original design. It’s vertical motion is directed by a drawer glide, and is powered by a system of pulleys. It has a spring loaded trapdoor bottom that drops down to allow the can to roll into the white bucket at the end of the catapult arm. Also pictured above is the tupperware container that holds all of the electronics- one Arduino, two bread boards, two PWM motor controllers, wiring for four motors, an IR receiver, and five touch sensors.

The above picture details the latch that holds the catapult in the ‘armed’ position until it fires. It is necessary because the winch that cranks the arm must be unwound for launch.

Pictured above and to the right are the two 42 in-lb. torsion springs that power the catapult as well as the reel that keeps tension on the catapult arm winch line when the winch is unwound.

In the picture to the right, you can see the arm winch motor oriented horizontally, the smaller latch motor oriented vertically, and the larger vertical motor that powers the rotational movement of the ‘turntable.’

Click on pictures to view larger version.

ACCESS THE ARDUINO CODE FOR THIS PROJECT HERE