Hi guys I am using HC-SR04 to detect water level inside a water bottle. I need to make it water proof so that the sensor doesn't gets corrupted by water.
I tried to use a polythene, by covering both the transmitter and receiver with it separately, but that is not working.I get wrong and extremely fluctuating readings with that. I think the reason is that a lot of noise gets absorbed and also the plastic keeps vibrating because of air around.
Then I tried using a food plastic wrap, which is very much thinner than polythene's material. This is working better, it gives a stable result at least. But for short distances, it gives two values, for eg. one reading will be about 400 and right after that, it will give something around 20,000. And this pair of results keep repeating for same distance.
What would be a good way to water-proof it? The waterproof ultrasonic sensors available in the market are very expensive, hence I am more interested in modifying this one if possible.