Hi,
in my project need measure water level in tank. I use ultrasonic sensor HC-SR04 but this is not waterproof and when I use this longer then they can damage. Need minimal distance 3cm not 30cm as car waterproof
ultrasonic sensor. Have you any idea how I can measure water level?
If you just need to know full or not: float switch.
Otherwise maybe a pressure sensor.
Use a pressure sensor. The water height in meters above the sensor is directly proportional to the water pressure.
You mean use waterproof pressure sensor in tank and convert pressure to water level? I find MS5540C sensor.
That one works well, but would have to be placed at the bottom of the lake to measure the water pressure there, and you have to add an atmospheric pressure sensor as well to compensate for atmospheric pressure.
For use with a bubbler you need a differential pressure sensor, such as the MPXV5004DP or the MPX5010DP - note, they come in various pressure ranges, pick the one that can handle your tank's expected maximum range.
I find video on youtube where using this sensor for get water level in cm. My water level range in tank is 3-25cm.
People don't use HC-SR04 when waterproof-ness is required, here is a waterproof ultrasonic sensor for your case: Sealed Waterproof ultrasonic/distance small blind sensor arduino Fully Genuine | eBay