I've searched the forum, but didn't found any relevant bathroom-related projects. I want to make a shower that keeps the user defined temperature and flow. My shower mixer is a mess when it comes to manually adjust the knobs - it has two states - arctic freeze and hellish hot.
I imagine this project to have 2 valves (1 on hot water, 1 on cold water) mixing the water, 2 DS18B20 temperature sensors (1 on hot water, 1 on the mixed output) and user controls for setting the desired temperature and flow power. There will also be a hall flow meter and a LCD. I have read on the topic of PID controlling and I am eager to try it.
There are couple of unknowns for me.
1. I will have to put a temperature sensor in the pipes. I don't know anything of pipes and water works. Of course everything will be tested properly on the bench before I'm going to ruin the actual shower
The question is can I waterproof the sensor with hot glue? Or should I use only bathroom-grade silicon?
2. Most of the solenoid valves I've seen have two states - open and closed, but I will need a flow control. Like 10% open or 50% open. I've read this can be accomplished with PWMing the valve. Is any valve suitable for this? Won't PWM drastically reduce the valve lifespan?
3. Housing for the mcu, display and wiring. I suppose any IP66-rated case will do the work? I am concerned of condense within the box.
4. Water resistant potentiometers for defining the temperature and desired flow. I have not seen any in the shops. Can you direct me to something? I think I'm getting the search terms wrong.