The official pentax IR trigger is very expensive and hard to get around here. And I really needed one, fast. So first I thought I would find some old Phillips TV remote, which is supposed to work to trigger the camera, but then I remember I still had a microcontroller development board and a few spare parts, including a IR led, lying around.

So this basic IR remote was born:



It is based on the Texas Instruments MSP430 chip, and the associated Launchpad development kit, both things come together and cost less than $5. I only added a resistor and an IR ED. The code took a few hours to write, thanks to the folks at 43oh.com and specially user oPossum on their IRC channel. He or she wrote a much more elegant version of my original code, and allowed me to use it for my project. Thanks also to whoever found out the pentax IR code.

Apart from the basic manual trigger mode, you can enter a timelapse mode by holding the button pressed, and it will keep triggering the camera at the interval you were shooting before. Oh, and it also should work with Nikon & Canon (but I haven't tried)

This is my first practical electronics project, and I am quite happy about the results.

Of course, still many improvements can be done. First I will move the circuitry to its own board (will only need a handful of components), then create some kind of enclosure with a battery holder. The software isn't really optimized for low power (one of the merits of this microcontroller family), which would be nice to have it run from a coin cell for a long time.

Finally, this thing being completely programmable, it should be easy to add other trigger sources, e.g. light and sound triggers, proximity and vibration detectors, etc.

[c-meier]

Quick update: I moved the circuit to its own board and added an enclosure, plus coin cell:



This is the schematic I used:

The values were chose by the "whatever I find first" method. One problem is reach. It is only about 1.5 meters. Maybe that output transistor stage could be improved.
EDIT: The above resistor labeled 2k should be 220. The transistor I am using is a 2N4401