In early 2000 my housemate Andrew Barrow and I designed a display system for the Queen's Solar Car. We used two PIC16F84 microcontrollers, and the module communicated with the rest of the car over a CAN-BUS system. After our breadboard prototype was complete and debugged we used a CAD program to print a scale layout with a laser printer. We used an iron to transfer the ink from the layout to the copper, which allowed us to etch our board.

The system displays the actual speed and target speed on the two dual seven segment displays. These are controlled by one PIC16F84 which multiplexes over the four digits. This PIC receives its data from the master PIC via a SCI routine I wrote. The two LEDs are signal light indicators which also support four way flashing. They are controlled by the master PIC. The master PIC also controls the LCD, again via SCI. On the LCD is displayed the motor's voltage and current and the solar array's voltage and current. All data is retrieved over the CAN-BUS system by the master PIC.

Source:  bus.txt  master.txt  slave.txt