I have spent the weekend watching the Oculus Rift keynotes on TwitchTV, and putting together the Polymerase Chain Reactor. The design for the case was created in Illustrator, and laser cut from black 5mm acrylic plastic. I would have preferred to use my 3D printer, but it's out of action, and there's no chance I can get this project finished in time AND rebuild my DIY printer with this deadline. It uses interlocking tabs to hold together, but it's still missing a nice hinge mechanism between the top and bottom compartments. Does anyone have an elegant solution for me?
Each heating element uses a 10 Ohm, 11 watt ceramic resistor, and an Microchip MCP9805 temperature sensor on I2C to the Atmega328. They are wired up, and the separate boards held together by a short piece of wire. Of course the final design will use custom PCB's, but there's not much time left in the competition, so I have had to hand-solder the surface mount parts...
The wires to the surface mount chip are VERY delicate, so I used a blob of hot-glue to give them some support. Then the case was snapped together around the completed heating/sensing system.
The main-board is not yet complete. It will use the Atmega328P, with an Arduino-compatibleUSnooBie bootloader, so it doesn't need an FTDI chip for USB programming, and can act also as a HID device. It will use a cheap HC-05 bluetooth module for serial communication to the controlling computer. I hope to have a great-looking Processing based GUI for the PCR machine control and access online databases, but with time running out, I might have to make an alpha App with python and TraitsUI.
More to come soon!