Waterproof for 'MS5540-CM'(Water pressure sensor)

Hello.
I have a problem for using 'MS5540-CM'

When I use this sensor, there was a malfunction.
There wasn't any wrong about sketch and circuit
because I've followed seller's manual(both sketch and circuit)

So I've searched from youtube and then I've heard that when using 'MS5540-CM' in water, waterproof should be done.
So I want to waterproof it.
This sensor is not as big as it looks in the picture.
Its size is approximately similar with one index finger.
Very small so that is hard to waterproof maybe.
How can I waterproof it?
I want to know method and tool. What should I prepare?

Actually I've waterproofed once using silicon and swab, but failed.
I think maybe there was a gap.
I want sophisticated waterproof.

And I want to know the role of orange color square that is near with pressure measurement(White circle in center)
Should I waterproof it also?

And also I should connect cable to port in sensor that you can see from picture.
Should I waterproof the gap between port and cable?

I'm South Korean, and I have low level for english so you can get hard to understand what I'm
talking about.
Please understand me.
Thanks.

Firstly why do you need to waterproof it ?

You won’t successfully water proof it as it is , it needs to be in some kind of enclosure.

The sensor element itself is only suitable for dry conditions ( see data sheet ) .

Some idea if your project might help

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That's a breakout board for the pressure sensor.
It's really for evaluation.
Have you looked at the data sheet?
After a quick read, it seems that you can expose the circular disc of the sensor to water.
The data sheet refers to using an "O" ring seal.
As far as I can see, looking at the image on the data sheet and your image, the seal must be made on the wall of the stainless steel cap and needs to sealed before getting anywhere near the square base of the sensor itself.
To use that board under water, you need some engineered tube with an internal "O" ring to slide over the stainless steel wall.
That tube could be in contact with water, open to the water pressure.
The tube would then have to be sealed to an enclosure rated at least IP69 to protect the board and the cable to the header pins would need to pass through an IP69 cable gland.
When I say tube, it could be a machined hole in an enclosure.
It seems to be rated for 10-bar or 100-metres depth, but only the stainless steel and circular disc "can".
A word of warning. "O" rings only work well if they are contained in a groove or similar to stop them spreading.
Your biggest challenge is going to be engineering a good seal.
You might get away with a tight fitting tube and a good adhesive.
Another solution might be to pot the whole thing in resin, leaving just the circular disc exposed.
That does mean though if anything goes wrong, like wrong connections, you are stuffed.
At a guess, the orange component is the 47uF Tantalum capacitor specified in the data sheet.
The manufacture also refers to a wet/dry cycle that implies that this is not suitable for continuous immersion.

1 Like

@hammy
The data sheet says:-
The version MS5540-CM carries a metal protection cap filled with silicone gel for enhanced protection against
humidity. The properties of this gel ensure function of the sensor even when in direct water contact. This feature
can be useful for waterproof watches or other applications, where direct water contact cannot be avoided.
I'm not too sure what they mean by silicone gel.
I know what silica gel is and I know what silicone is.
The only thing I heard of with silicone and gel in the same breath are breast implants.

1 Like

I'm going to use this solution, and tell you results.
If it is not solved, Could you tell me another way?
Thanks :slight_smile:

I'm going to use this solution, and tell you results.
If it is not solved, Could you tell me another way?

Which solution exactly are you going to use?
You need to read the TE Connectivity datasheet for the device - forget the board you have, it's not for immersion in water.
There is a section about humidity and water protection - get it translated.

You have been told how. The datasheet says use an "O" ring.
If I were you, I would get your board wired up, tested.
If you want to see how it works under water, get a potting box, some resin and fill it up until all you can see is the round disc and the cable you have fitted.
Then put it in some water and see what happens.
We look forward to hearing your results, but until then, no more solutions.