Use of STK500 and Atmel Mega32 MCU in lab $15
SD Card Connector from Digikey (HR845CT-ND) $3.80
32 Megabyte SD card Previously owned
Wires, LED, pushbutton, solder Free in lab
Total cost: $18.80

Block diagram of the major components of kaOS

Stepup circuit to change 3.3V from the card to the 5V required by the Mega32

Stepdown circuit to change 5V from the Mega32 to the 3.3V required by the card

Voltage regulator to provide a steady 3.3V.
Most of the work we did on kaOS was done together, either coding at the same screen or working out the design together.  Toward the end of the semester, to maximize our time, we divided the labor a bit.  Nick worked more on the operating system functionality while Adam built the circuit and worked on reading from and writing to the SD card, even though this division of labor is a bit ironic given our majors.  In the last several days before our demonstration, we came back together to get the loading working with the operating system.

Nick and Adam