Making HC-SR04 waterproof

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.

Thanks

Waterproof ultrasonic sensors are expensive for a reason.

You aren't likely to have much luck with your own waterproofing experiments, because that will interfere with both the transmitter and receiver, which are designed to function in dry air.

A better way to measure water level is to measure the pressure at the bottom of the container. It is proportional to the height of the water column.

Do you really need a waterproof sensor?

I am also using a HC-SR04 for detecting Water level inside a box. Sensor is mounted at the top, but without direct water contact, so it does see only the humidity.

This system is working since 10 Months without any issues. (exept the 25µs dither described above)

guntherb: Do you really need a waterproof sensor?

I am also using a HC-SR04 for detecting Water level inside a box. Sensor is mounted at the top, but without direct water contact, so it does see only the humidity.

This system is working since 10 Months without any issues. (exept the 25µs dither described above)

I think I do need a water-proof one, since I plan to fix the sensor at the cap of the bottle, and if a user will tilt the bottle, then water can go inside the transducer and circuit.

jremington: Waterproof ultrasonic sensors are expensive for a reason.

You aren't likely to have much luck with your own waterproofing experiments, because that will interfere with both the transmitter and receiver, which are designed to function in dry air.

A better way to measure water level is to measure the pressure at the bottom of the container. It is proportional to the height of the water column.

I tried measuring the pressure at the bottom using a FSR. That is not giving very accurate readings. All load cells are pretty costly. Can you suggest a cheap option for measuring pressure.

can you put parellel wires down to the bottom ,

Measure the capacitance between them.

Boardburner2: can you put parellel wires down to the bottom ,

Measure the capacitance between them.

I am avoiding any contact with the water, since I want to measure for potable water. Wont the presence of the wires inside the water harm it?

you can use carbon fibre rods.

You do not need to pass current through the water just measure capacitance

Boardburner2: you can use carbon fibre rods.

You do not need to pass current through the water just measure capacitance

Thank you so much for replying.

Excuse me for not having much information about this method. I have two doubts:

  1. Is Carbon Fibre food safe?
  2. For the method, what I understand is that the two wires will be connected to a battery. Can this result in ioninsing the water?

manisha20: Thank you so much for replying.

Excuse me for not having much information about this method. I have two doubts:

  1. Is Carbon Fibre food safe?
  2. For the method, what I understand is that the two wires will be connected to a battery. Can this result in ioninsing the water?

food safe i do not know.

this is

https://www.adafruit.com/products/1786

Thats resistive but for capacitance insulated wire can work with no direct contact with the water.

Just a case of finding a food safe insulator.

Anything commercial is likely to be expensive.

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Cheaper and longer lengths of eTape liquid level sensors

https://www.whiteboxes.ch/shop/etape/

https://milonetech.com/products/standard-etape-assembly

lifehack

Doesn't that cling film affect the sensor operation and accuracy?

Yeah I think it does affect accuracy and proper operation. HC SR04 is inherently NOT a waterproof sensor.

There are specific waterproof sensors for this purpose.

JSN SR04T being one but it has only 1 transducer/sensor and therefore has a minimum blind distance of 20cm.

There is this another sensor which has 2 transducers/sensors helping us get minimum distance of 3cm and is also IP67 rated