SensirionSmartGadget

https://www.sensirion.com/en/products/digital-humidity-sensors-for-reliable-measurements/development-kit/

Sales blurb:

"The Smart Gadget not only shows humidity and temperature values on the display, but can also communicate with a bluetooth SMART capable device like a smartphone."

How to communicate the Raspberry Pi?

This is done with a Raspberry Pi 2B running Ubuntu Mate, but should work on other distributions.

Use a compatable USB Blurtooth dongle

I use the Plugable one: http://www.amazon.co.uk/Plugable-Bluetooth-Adapter-Raspberry-Compatible/dp/B009ZIILLI?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00 Others may work.

Install the BlueZ package

I downloaded the latest version from https://www.kernel.org/pub/linux/bluetooth Install instructions can be found here http://www.elinux.org/RPi_Bluetooth_LE#BlueZ_installation Or you can install from the repositry, but I didn't test this

$ sudo apt-get install bluez bluez-utils

Test connecting

Press the button on the sensor gadget to switch on the bluetooth radio. Then :

$ sudo hcitool dev
Devices:
    hci0    5C:F3:70:75:C9:7B

$ sudo hcitool lescan
LE Scan ...
98:D6:BB:22:0B:19 (unknown)
98:D6:BB:22:0B:19 (unknown)
DC:88:34:2D:8E:DB (unknown)
DC:88:34:2D:8E:DB Smart Humigadget

$ sudo gatttool -I -b DC:88:34:2D:8E:DB -t random
[DC:88:34:2D:8E:DB][LE]> connect
Attempting to connect to DC:88:34:2D:8E:DB
Connection successful

Reading the sensor data.

For this you need to know the UUID of the sensors. This can be found in the documentation from the Sensiron GitHub site.

TEMPERATURE_UUID="00002235-b38d-4985-720e-0F993a68ee41"
HUMIDITY_UUID="00001235-b38d-4985-720e-0F993a68ee41"
BATTERY_UUID="2A19"

From the gatttols prompt:

[DC:88:34:2D:8E:DB][LE]> char-read-uuid 00002235-b38d-4985-720e-0F993a68ee
handle: 0x0037   value: 00 00 b2 41

The value is a 32bit little-endian floating point number. See bttest.py to see how to convert it to a readable number.

Reading from a python script

I use the pygatt library. https://github.com/peplin/pygatt Install using pip

pip install pygatt

See btread.py to see how to read the sensors.

thermo2016 / SensirionSmartGadget

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