Halloween is only a few days away. We're getting into the spirit by building a remote control color changing pumpkin. Channel buttons 0-8 on the remote toggle the colors of the rainbow. Button 9 activates an 'angry pumpkin' mode that flashes a scary red strobe for a few seconds.
It uses a minimal PIC 18F2550 circuit that decodes the remote control signals and drives a ShiftBrite color changing LED module. The F2550 is a USB PIC with a USB bootloader, so it's technically a USB upgradable pumpkin too.
Happy Halloween from Dangerous Prototypes!
Step 1: IR receiver
The IR receiver converts infrared light from the remote control into a signal that the PIC microcontroller can decode. The receiver is connected to PORTB pin 2 (RB2) of the PIC. RB2 has an external interrupt with edge select that we used to trigger the IR decoder. RB2 also has a Schmitt buffer that cleans the incoming signal and helps prevents false triggers. All PORTB pins on the 18F2550 have internal pull-up resistors if your receiver is an old type that doesn’t have it’s own pull-up.