Thursday, February 27, 2014

Andre Le - Egg Drop

For this Egg Drop project, we needed to design a shock proof enclosure for an Arduino circuit that was to be dropped off of the top of the 3-story CFA building. 

I tried experimenting with techniques that I have not tried using before and improvising along the way. 

I started with the circuit design:

The goal of this was to use the space savings gained by the Arduino Micro to the best of my ability. I used a piezoelectric sensor as an input to detect vibrations. This eliminated the need for an external switch to activate the output. I also knew that the piezoelectric sensor could be turned into a transducer by applying voltage through it. Unfortunately, I needed PWM pins to create the sounds and Analog pins to read the input. However, after digging into the documentation for the ATMega328 chip onboard the Arduino, I realized that it has several pins that can be used as analog input as well as PWM output. After some breadboarding, I found that I could the piezo sensor into both an input AND output simultaneously.

By keeping the number of components down and the footprint small, I could make a smaller and lighter box in hopes that it would reduce the impact of the fall. I measured the size requirements with my digital calipers and created a tool path for the laser cutter with those dimensions in mind.

The material I used was basswood, with the hopes that the soft wood would be less brittle than a dense hardwood. The slices were aligned and glued together with wood glue. Holes were drilled for the screws and countersunk to be flush with the surface. The final piece was sprayed with Shellac to protect the surface. 

Let's hope this isn't the last time we see this alive.

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