The challenge:
Control a TV or other IR device via a non-circuit based device powered by a candle for IR source. Batteries not allowed.
You can use a candle, paper, cardboard, plastic, lenses, aluminum cans etc. All hand made unpowered and rudimentary materials allowed.
You may obtain the ir message by any means including a detector, DAC, etc system. But once you have your code, those devices cannot be used.
Candle + IR opaque strip. Cut notches in strip according to desired pattern. Run strip in front of candle sufficiently quickly (remote signals can have very high bitrates so in practical terms it may not be possible).
Putting the notches around the edge of a disc might make it easier to move fast enough.
According to this we’re trying to do 36kHz. So 36 slit positions around the circumference of the wheel would mean 1000 rps or 60,000 rpm, 360 would mean 6000 rpm. A fairly large wheel with 1 bit per degree spun at 6000 rpm might be achievable if we can get some gearing involved.
Something I just thought of: If the slits are thin, you need a second, stationary IR blocking plate with just a slit in it that sits in front of the candle to prevent any spillover into the next or previous slit of the wheel due to the width of the candle flame.
I’d put the candle in a box with a window of the same width and height as the notches, both to keep it from spilling over and also to keep the speed of the wheel from blowing out the candle. Probably put a lens in that window too to help with apparent brightness.
Could be fun to try.
Related, if you have a Nintendo Wii but have lost the “sensor bar” you can place two candles the correct distance apart and they work as a replacement. The “sensor bar” doesn’t actually sense shit, it’s just 2 IR projectors that the controllers are able to look at and orient themselves