JustDIY shows us how he reverse engineered a Pentax DSLR IR remote to make a DIY Pentax DSLR IR Interval Timer. By allowing the microcontroller to send the take picture command this project is now able to command the camera to take time lapse movies like the one after the jump. With a digital storage scope it is simple to capture this type of short waveform and duplicate it in code. The result is a nice and compact project that fits into a tiny mint tin.
“I connected the IR decoder to my o-scope and manually measured the pulse train. It was only 26 msec, and consisted of 15 transitions. 13 msec on, 2.8 msec off, and then 1 msec on/off repeated eight more times. Using the 12F683 chip (one of my favorites), I had access to an 8MHZ internal clock and a hardware PWM module. Microchip claims the hardware pwm maxes out at 20khz, but I had no trouble getting a stable 37khz carrier out of it.”
