Raspberry Pi Environmental Sensing

This project is a personal sensing station that uses Raspberry Pi, HTU21D (indoor temperature/humidity), AM2306 (outdoor temperature/humidity) and PMS7003 (particle matter level). It supports logging measured sensory data locally and submit to a MQTT broker and/or a MySQL database.

• Raspberry Pi is a popular open-source hardware. This program is tested on RPi Zero W, but should support all versions of RPi.
• HTU21D is a high precision temperature + humidity sensor and it is connected to RPi via I2C_1.
• AM2306 is an outdoor temperature + humidity sensor, which uses the DHT22 chip. It is connected to RPi via Pin 7.
• PMS7003 is a laser particle matter sensor. It connects to the RPi using the serial port.
• MQTT is a subscribe/publish message protocol designed for light-weight IoT devices.
• MySQL is a relational SQL database.

1. Requirements

• Python >= 3.5
• To use AM2306/DHT22:
  • Install RPi.GPIO: sudo apt-get install python-rpi.gpio
  • Install the Adafruit driver: https://github.com/adafruit/Adafruit_Python_DHT
• To report to a MQTT broker: https://pypi.org/project/paho-mqtt/
• To report to a MySQL server: sudo apt-get install python3-pymysql

2. Usage

1. Change to home directory: cd ~
2. Clone the project: git clone https://github.com/automaticdai/rpi-environmental-sensing
3. Edit the configuration file rpi-weather-config.json and save
4. Copy the configuration file to /etc: sudo cp rpi-weather-config.json /etc/rpi-weather-config.json
5. Run the main script: python3 main.py

You can run individual python script to test the sensor driver, e.g., python3 dht22.py

3. System Configuration

For the configuration file config.json:

Config

• sensor_id: assign a sensor ID to the device.
• sensor_name: name of the sensor. Used as the prefix of MQTT publishers.
• log_on: enable writing to a local log.
• report_periodic: run the script periodically/or only once.
• report_interval_sec: set the sampling and report interval (in second). If 'report_periodic' is false, this parameter will be ignored. Should be no less than 10s, otherwise it is difficult to guarantee.

MQTT

• enable: enable report to MQTT.
• server, port: MQTT broker IP and port.

MySQL

• enable: enable report to MySQL server.
• host, port: database IP and port.
• user, password: login user information.
• db, table: database and table name (should be an existed database).
• charset: character set

4. Credit

• Adafruit for the HTU21D and DHT22 drivers.
• Eclipse Paho project for the MQTT driver.