# Someone using reliable OUTDOOR Humidity Sensors?

**URL:** <https://www.thethingsnetwork.org/forum/t/someone-using-reliable-outdoor-humidity-sensors/32282>\
**Category:** End Devices (Nodes)\
**Created:** [December 1, 2019, 5:34pm UTC](https://www.thethingsnetwork.org/forum/t/someone-using-reliable-outdoor-humidity-sensors/32282 "2019-12-01T17:34:28Z")\
**Posts on this page:** 1\
**Showing post:** 39

<div class="post-metadata">

**Author:** ![bluejedi](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/bluejedi/32/44639_2.png) [@bluejedi](https://www.thethingsnetwork.org/forum/u/bluejedi)\
**Post date:** [February 7, 2020, 9:52am UTC](https://www.thethingsnetwork.org/forum/t/someone-using-reliable-outdoor-humidity-sensors/32282/39 "2020-02-07T09:52:54Z")

</div>

Have you looked at the SHT31 and Si7021 sensors with membrane/PTFE filter?  
The versions with membrane/PTFE filter are rated for IP67.

SHT31 was previously mentioned in: [The WORKBENCH part 1](https://www.thethingsnetwork.org/forum/t/the-workbench-part-1/8970/109)

### SHT31

- Sensirion [SHT3x product page](https://www.sensirion.com/en/environmental-sensors/humidity-sensors/digital-humidity-sensors-for-various-applications/)

- [SHT3x Membrane datasheet](https://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/0_Datasheets/Humidity/Sensirion_Humidity_Sensors_SHT3x_Datasheet_Filter_Membrane.pdf)

### Si7021

- Silicon Labs [Si7021 product page](https://www.silabs.com/sensors/humidity/si7006-13-20-21-34)

- [Si7021 datasheet](https://www.silabs.com/documents/public/data-sheets/Si7021-A20.pdf)

* * *

Sensor modules based on Si7021 with filter are available on AliExpress:

> **[US $2.0 |Humidity Sensor with I2C IIC Interface Si7021 Industrial High...](https://www.aliexpress.com/item/32695384846.html?spm=a2g0o.cart.0.0.451e3c00T7L6KG)**
>
> Smarter Shopping, Better Living! Aliexpress.com

A possible option to protect the rest of the electronics from moist and water is by covering (painting or spraying) it with _(the sensor itself should not be covered of course)_:

- **Liquid Electrical Tape** (LET)  
Manufacturers: Star brite, Permatex, Performix.

- **Plasti DIP**  
Similar to LET (but possibly thicker).  
For electronics a thin layer better preserves cooling properties.

For reliable measurements you will still need a proper housing that protects the sensor from rain and (direct) sun light and that allows for sufficient ventilation. E.g. something like:

> **[US $6.23 19% OFF|plastic outer shield for thermo hygro sensor, spare part for...](https://www.aliexpress.com/item/32793243933.html?spm=a2g0o.cart.0.0.7ef03c00gK3nMi)**
>
> Smarter Shopping, Better Living! Aliexpress.com

* * *

A compact DIY outdoor weather station could be build with a Heltec CubeCell HTCC-AB01 board + Si7021 module + BMP280 module and above plastic outer shield. The CubeCell board supports Li-ion/LiPo batteries and solar panel charging and uses only 8.5 uA in deep sleep when powered by Li-ion or LiPo battery.

* * *

### Sensor Tests

Some tests with above sensors: [http://www.kandrsmith.org/RJS/Misc/hygrometers.html](http://www.kandrsmith.org/RJS/Misc/hygrometers.html)

---

_[View the full topic](https://www.thethingsnetwork.org/forum/t/someone-using-reliable-outdoor-humidity-sensors/32282)._