There was a discussion some time back about using photosensors for chuff input in TMCC/RS4 upgrades. I ordered some RPR-220 reflective photosensors to try out not long after. The idea is to trigger fixed chuffs from a driver as opposed to using a tender wheel with magnets using the old 2 chuff/tender wheel dia. = n chuff/driver dia. where n chuff is close enough but sometimes too low.
My current 3rd Rail J1a project seemed to be a good candidate for a bit of analog electronic tomfoolery. I am using a classic Lionel RS4 3 board setup with the chuff input on the m/b. This input reads 5VDC when open. The m/b I have is fairly similar to some of the small TMCC steam with tethers from the early 2000s.
In any case, tonight’s little experiment is promising. Here’s a vid of the first problem encountered:
Here’s a chicken scratch of the circuit I cobbled up:
I was wondering if anyone else has experimented with these. There are quite a few smaller versions out there. In any case, seems promising!