Raspberry Pi Weather Sensor

Temperature, Weather and Light Reader for a Raspberry pi (any model)

These instructions are for a simple Raspberry Pi project that can be used in any home automation, to collect temperature and humidity data. Just plug it in, configure the MQTT path and forget!

Needed parts:

• A Raspberry Pi Zero. Or any Raspberry Pi.
• Any MicroSD card.
• A USB WiFi dongle (if not built into the Raspberry already)
• An HTU21D-F Temperature & Humidity Sensor
• Any microUSB power source

Step 1: Create the OS

Note: We can skip plugging the Pi into a TV and keyboard by configuring the SD card directly from your computer. If you'd rather do this directly from the booted Pi, that works too!

1. Download Raspbian Jessie Lite and image it onto an SD card

2. Mount the SD card on your computer. Easiest is to follow the RPi guide

3. Add an empty file named ssh to the boot partition. This enables the ssh daemon. This can be done via terminal / PuTTy and then sudo touch ssh

4. To setup the wifi headless (e.g. without having to add a usb-network adapter and cable), then:

   • Create a file called wpa_supplicant.conf by using the command sudo nano wpa_supplicant.conf
   • Add the following to this file

         network={
             ssid="your WiFi name (SSID)"
             psk="your WiFi password"
         }
     

   • Save & Exit. Ctrl + X if using nano

5. Eject the SD card, insert into Pi, and plug it in. It should now automatically come onto your wifi.

6. Via SSH, log into the raspberry pi and ensure it's up 2 date

ssh pi@YOUR.IP.ADR.RESS (password: `raspberry`)
sudo apt-get update
sudo apt-get upgrade

Step 2: Create the hardware

1. Disconnect the Pi and

2. Add the HTU21D-F Temperature & Humidity Sensor to Raspberry Pi GPIO pins.

3. Plug in a power source, and you’re good to go again.

Step 3: Create the software

After you ssh to the pi, install a few essential libraries:

sudo apt-get --assume-yes install python-pip i2c-tools git python-smbus

Set the timezone to make sure timestamps are correct

sudo raspi-config
[Internationalisation Options]
[Change Timezone]
[Interfacing Options] --> [I2C] --> Enable / Yes

Clone the weatherSensor github repository

sudo git clone https://github.com/ulnic/weatherSensor.git

Install weatherSensor dependencies (this includes RPI.GPIO and MQTT PAHO)

sudo pip install -r weatherSensor/install/requirements.txt

Set permissions in case of for all files and directories

sudo chmod 755 -R *

Create the settings file /home/pi/weatherSensor/config/configuration.ini. This file specifies what sensor pin to monitor, what messages you want, and what services to send the message to. Configure as per below:

• If first time, make a copy of configuration.ini.sample and call it configuration.ini. This file name is important
• Configure the sections and key-values accordingly.

Edit /etc/rc.local to make the program run when the device boots up.

Add before the exit line:

# Execute weather sensor automatically at start up
sh /home/pi/weatherSensor/reboot_script_weatherSensor.sh 

You’re done! Reboot and test it out.

Step 4: (Optional) Setup Home Assistant

This weatherSensor works great with Home Assistant and a MQTT Broker. Configure your Home Assistant yaml file similar to below:

- platform: mqtt
  name: "Bedroom Temperature"
  state_topic: "weatherSensor/bedroom/rpi"
  value_template: '{{ value_json.temperature }}'
  unit_of_measurement: "°C"
  qos: 0

- platform: mqtt
  name: "Bedroom Humidity"
  state_topic: "weatherSensor/bedroom/rpi"
  value_template: '{{ value_json.humidity }}'
  unit_of_measurement: "%"
  qos: 0

- platform: mqtt
  name: "Bedroom CPU"
  state_topic: "weatherSensor/bedroom/rpi"
  value_template: '{{ value_json.cpu }}'
  unit_of_measurement: "C"
  qos: 0

- platform: mqtt
  name: "Bedroom IP"
  state_topic: "weatherSensor/bedroom/rpi"
  value_template: '{{ value_json.ipaddress }}'
  qos: 0