OK, before you think I’m really going down the rabbit hole here… I bought one of these Auto-Flush Kits from Amazon.com with the intention of either hacking it or “using it as inspiration” to produce something similar, shall we say.
It is very nicely designed with a rotary servo motor that is (Schmitt) triggered and pulses a voltage in two directions to get a forward and reverse rotation. A (nicely placed) SMT hall effect sensor with a corresponding RE magnet on the armature are used to stop the rotation during the “un-flush”. A PIC MCU orchestrates everything, the device works well.
My impression is that it is extremely well constructed. The electronics are potted in the lid of the enclosure in such a way that I cannot see what kind of sensor is used without completely destroying the unit. My assumption is that it is using a microwave/RF sensor. It seems reliable and I am very impressed with the quality of the unit, the sensor reads through the ceramic tank top quite easily and reliably.
So onto the point… I have a vacation home which can be vacant for some time. I have a friend who will come into the house on occasion (which is to say he remembers usually at least once in the few days that precede our return) with the intention of keeping the toilets’ seals working and keep water in the bowl (prevents critters and gasses from coming out of that nasty open hole if the water evaporates away).
So, Particle to the rescue. I can easily make one of these, but this would be a lot easier if I could just spoof the microwave sensor on this unit. Would anyone know an easy way to accomplish this? I can easily add another hall effect sensor to restart a timer for a manual flush, but I want to be able to trigger this programmatically.
Any advice out there on triggering this type sensor without tearing the unit apart? I’d prefer it to be electronic (i.e. I don’t want a servo on the top/inside of the tank with some kind of flapper to activate the sensor).
Any ideas would be appreciated