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Temp/hum sensor failing again

Discussion specific to Davis weather stations
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steve
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Temp/hum sensor failing again

Post by steve » Fri 04 Sep 2015 7:03 am

My VP2 temp/hum sensor is failing again (sporadic high temps, humidity too low). This one has lasted three years, so that's an improvement on the previous ones, which typically lasted between 9 and 18 months.

I'm wondering what my options are for replacing it at less cost than the official part - I believe some of you have used third-party replacement boards, or repaired it using replacement chips? Any good suggestions? I'm semi-retired now, so I have to make savings where I can ;)
Steve

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mcrossley
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Re: Temp/hum sensor failing again

Post by mcrossley » Fri 04 Sep 2015 8:11 am

I replaced mine with a SHT-75 mini board. It is a direct wire-wire replacement for the Davis board - though you have to solder it on. I then encased to solder joints and mini-board (apart from the sensor chip itself) in epoxy. It is very small and the existing wire clip is fine for holding it place. To protect the sensor I placed mine in a tiny 'bag' made from some of my daughters old tights!

For you I think the key thing is finding a suitable enclosure for the sensor to keep the salt out. The Davis sensor enclosure on their boards is useless for this, it is just a wire mesh. The Sensirion supplied cover is of a permeable membrane type (think Goretex type stuff) - far superior.

I think Belfryboy offers a board with the Sensirion sensor cover, but I could be wrong.
Last edited by mcrossley on Fri 04 Sep 2015 9:35 am, edited 2 times in total.

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steve
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Re: Temp/hum sensor failing again

Post by steve » Fri 04 Sep 2015 8:26 am

Thanks, Mark. I'm happy to do soldering, but I think maybe I'll investigate Belfryboy's ready-built solution, if he's still doing them.
Steve

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Re: Temp/hum sensor failing again

Post by AllyCat » Fri 04 Sep 2015 9:21 am

Hi,
mcrossley wrote:The Sensiorion supplied cover is of a permeable membrane type (think Goretex type stuff) - far superior.
Is that supplied with a "real" SHT-75 sensor or an "optional extra" - I can't find any reference to it?

FWIW, the "best price" I've found (in a brief Google) for a Sensirion SHT-75 from a "well-known" supplier is £23.60 from CPC-Farnell plus VAT, but shipping should be free (Royal Mail) even to the Northen Isles? RS and even the main Farnell site seem somewhat more expensive.

Cheers, Alan.

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Re: Temp/hum sensor failing again

Post by mcrossley » Fri 04 Sep 2015 9:35 am

The Sensirion covers are made for the SHT1x sensors http://www.sensirion.com/en/products/hu ... for-sht1x/

You are on your own for the SHT7x boards.

That seems like a reasonable price.

I see they are releasing a SHT3x series, wonder what the pricing on those will be like, and how compatible with the ISS they will be - they are dual I2C and voltage outputs.

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Re: Temp/hum sensor failing again

Post by AllyCat » Fri 04 Sep 2015 9:54 am

Hi,

Thanks, that's very interesting. The covers seem surprisingly cheap (for the application), less than £3 from ebay.co.uk , a little over from CPC and significantly less from RS, etc..

Cheers, Alan.

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Re: Temp/hum sensor failing again

Post by duke » Sat 05 Sep 2015 6:34 am

steve wrote:.....but I think maybe I'll investigate Belfryboy's ready-built solution, if he's still doing them.
Had mine for over a year now without problem.
Duke

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