List of hardware

• ESP32-PICO-KIT
• HTU21D Digital Relative Humidity Sensor
• Breadboard
• 4 female-to-male jumper wires
• Raspberry Pi with Bluetooth
• Xiaomi Smart Temperature & Humidity Sensor

TODO: Add photos of hardware

Hardware setup

ESP32

Wiring schemes

ESP32	HTU21D
3V3	VIN
GND	GND
18	SDA
19	SCL

TODO: Add final picture of setup

Raspberry Pi

In this setup we use Raspberry Pi 2 Model B V1.1 with Raspbian GNU/Linux 9.8 (stretch) installed on it. It does't support Bluetooth, so you need a usb dongle. We use Grand-X BT40G. Make sure your dongle is recognized by system. You can check it with the following command:

$> lsusb
...
Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
...

Programming ESP32

You need ESP-IDF (Espressif IoT Development Framework) to program your ESP32. Install it with the following instructions:

mkdir ~/esp
cd ~/esp
git clone --recursive https://github.com/espressif/esp-idf.git
git checkout 3bf56cdd1

Set up IDF_PATH before running any other command:

export IDF_PATH=~/esp/esp-idf

The python packages required by ESP-IDF are located in IDF_PATH/requirements.txt. You can install them by running:

python -m pip install --user -r $IDF_PATH/requirements.txt

Note

Please check the version of the Python interpreter that you will be using with ESP-IDF. For this, run the command python --version and depending on the result, you might want to use python2, python2.7 or similar instead of just python, e.g.

See this guide for more info.

Now you can flash your ESP:

git clone name_of_rep_with_example
cd name_of_rep_with_example
make flash

Programming Raspberry Pi

There is a script in repo called main.py. You need at least python3.4. Install the following packages:

sudo apt-get install libglib2.0-dev
pip3 install bluepy btlewrap tb-mqtt-client

Run sudo python3 main.py and enjoy :::::::::)