What kind of a Sensor do I need

I’m trying to create my own touch-less toilet flush, similar to the Kohler Touch-Less Toilet Flush that sits inside the tank and can scene when why move your hand over it, it works through the lid of the tank. Any Ideas of kinda of sensor I would need to do this?


Use a retro reflective sensor. You can get different ranges from mm to metres.

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That looks like it works off of light which will not work, as it will be where there is no light and besides it needs to also work when the lights are off.

Retro reflective means that it senses light it sends out. The light it sends out is IR so cannot be seen.


weedpharma: Retro reflective means that it senses light it sends out

..... provided the thing it points at is retro-reflective (as opposed to mirror reflective).

If it works off light, how will the light pass thru the lid of the tank so that it will detect the presence of a hand?

Missed "through the tank".

Maybe near the tank.