Topic: Davis temperature sensor sht31 pinout

[Fede717]

Hello!

Does anyone knows the pinout of the cable of the Davis sht31 (new version) temperature/hum sensor board 7346?

I’m attempting to read The sensor with an Arduino, I’ve read that someone successfully did it.

Thanks in advance,

Federico

[doubleohwhatever]

I don't recall the exact pinout (99.9% sure it's mentioned in a thread somewhere on wxforum). However, make sure the library you're using to communicate with the sensor is using Sensrion Bus and not I2C.

This may help:
https://github.com/HydroSense/sensirion

[Fede717]

I don't recall the exact pinout (99.9% sure it's mentioned in a thread somewhere on wxforum). However, make sure the library you're using to communicate with the sensor is using Sensrion Bus and not I2C.

This may help:
https://github.com/HydroSense/sensirion

 thank you for the link you posted.
The post you recall could be this https://www.wxforum.net/index.php?topic=33836.msg343903#msg343903?
Reading the pinout, how can I connect the RH Vout and Temp Vout to sda and scl?

[doubleohwhatever]

Nah, that's not the thread. I just did a quick search and couldn't find it either.

I think it's something like this:

Yellow: V+
Green: V-
Blue: data
White: data

I don't recall which data would be the SCL equivalent and which would be SDA.

[johnd]

I'm not 100% sure why you would want to read a Davis T/H sensor with an Arduino? If I was doing that sort of thing, I'd choose a version of the SHT31 sensor that had a true I2C interface, something like:

https://www.cqrobot.com/index.php?route=product/product&path=107&product_id=1121

Or similar sensors from Adafruit etc. I guess the only issue is that this doesn't come with the Davis sensor's weatherproofing.

[Fede717]

I'm not 100% sure why you would want to read a Davis T/H sensor with an Arduino? If I was doing that sort of thing, I'd choose a version of the SHT31 sensor that had a true I2C interface, something like:

https://www.cqrobot.com/index.php?route=product/product&path=107&product_id=1121

Or similar sensors from Adafruit etc. I guess the only issue is that this doesn't come with the Davis sensor's weatherproofing.

I know there’s a i2c version and its easier to use. The goal was to replicate the dimension of the board to fit it in a Davis passive solar shield, But since I’ve a Davis board (I bought one used for 10 eur) the goal is to try to read it, cause I read here that someone already did it ( https://forum.arduino.cc/t/i2c-legacy-sensibus-lss/592035).
If it’s not possible, I’ll go for the i2c version, or better with an sht7x …

[doubleohwhatever]

Keep in mind that the used sensor will likely have drifted from the original calibration.

I'd honestly just go with a new I2C sensor.

[Fede717]

Keep in mind that the used sensor will likely have drifted from the original calibration.

I'd honestly just go with a new I2C sensor.

Oh, that’s a problem, many thanks for the advice! I’ll go with a sht71 digital version due to the length of the cable (approx 50m)
Just to fulfill my curiosity, I’ve to find out which pin is what, if I exchange sda with scl, do I make a mess or fry the sensor?

[doubleohwhatever]

Oh, that’s a problem, many thanks for the advice!

No worries. They're supposed to only drift up to 0.25% per year. However, until you've compared your used sensor to a reference sensor, you really won't know how little or how much it has drifted.

Just to fulfill my curiosity, I’ve to find out which pin is what, if I exchange sda with scl, do I make a mess or fry the sensor?

Nothing is guaranteed but you should be okay.

[azchrisf]

Just to fulfill my curiosity, I’ve to find out which pin is what, if I exchange sda with scl, do I make a mess or fry the sensor?

Nothing is guaranteed but you should be okay.

I'll add into that - probably nothing, I've done it before and from what I've found it just doesn't work until you put the right pairs together.
Again as doubleoh said YMMV.