Re: [Electronics_101] Re: pressure/vacuum switches
- problem solved - i hope.
i put a spring inside the water level sensor, well, it will now act as a
vacuum switch but the pressure is way too low, one would need a very, very
strong spring (maybe 20kg / 200N force). This doesn't work.
So the membrane is too large.
Then i thought of the solution: a thermostat.
A thermostat like in a fridge or freezer or heater of some sort is only a
metal bellow and a tube in which a gas is expanding due to heat. So i took
a old one and opened the tube end, and found it will react to 1 to 2
positive athmospheres of pressure depending where the control knob is set.
I'm positive this is fairly easy to modify it slightly so it will react at
a slightly lower pressure, and i will put it in some kind of container and
seal the wiring so it works with vacuum instead of pressure.
Seems like i found a $0 solution after all - tried for the analog pressure
sensors at ebay but they ended up too expensive.