To meet the project requirement of using a microcontroller, we decided to develop a giant Atmega328 with an Arduino embedded inside. This would be programmed to provide a jumper-selectable logic training application- various gates, latches, flip-flops, etc, as well as some combinatorial networks to be mapped out using K-maps or other methods. It would also have a zif socket to allow it to re-program stock Atmega328 parts in the field for use in student kits.
We also (naturally) opted to make a 555 timer IC.
The various methods we've tried have had differing levels of results. We used on of the CNC machines to cut a mold out of foam. We've tried vacuum forming as well. It seems that the most successful method is likely to be stacked layers of foamcore with a pocket carved out of the inside, and wire traced between layers back to the pocket. The chip itself can then be embedded inside or attached to a circuit board forming a substrate.
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Two PCB-based scaled chips. Home etched circuit boards, for 8-pin devices. The pins are banana plugs pushed through the hole and screwed down. There is no cosmetic cover plate- this could be added, or it could be left bare to improve visibility. | The post-carving IC, top half. We made two halves so we could sandwich them around the works inside. |
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The innards of the Atmega328P model. Each pin wires up to the appropriate Arduino pin. | The completed Atmega328P, on the breadboard. |