weather-monitor

Introduction

A weather monitor using a Raspberry Pi, BMP085 and DHT22 sensor, uploading to IoT platform ThingSpeak and Slack using their web apis. https://au.mathworks.com/help/thingspeak/update-a-channel.html https://github.com/raddevon/pyspeak

After you've got it working you could set the filesystem to read only to save SD card wear (https://hallard.me/raspberry-pi-read-only/, or like me just disable swap and log to RAM: http://raspberrypi.stackexchange.com/questions/169/how-can-i-extend-the-life-of-my-sd-card)

Hardware

Tested on: Rapsberry Pi Model A (original)
Adafruit BMP085 temp and pressure sensor

• VCC -> 3.3v
• GND -> GND
• SCL -> GPIO 03
• SDA -> GPIO 02

DHT22 temp and humidity sensor

• pin 1 -> 3.3v
• pin 2 -> GPIO 08 (inside sensor connected to GPIO07)
• pin 3 -> NONE
• pin 4 => GND

Shinyei PPD42NS particle sensor pin 2 must have a voltage divider to reduce 5v to 3.3v for Pi

• pin + -> 5v
• pin 2 -> GPIO 07
• pin - -> GND

Accounts

You'll need a thingspeak account, and to create a channel with three fields, and get your API key You'll need a slack account, and to get your API key

Installation

1. Starting with Raspbian Jessie Lite, update the system:

sudo apt-get update
sudo apt-get install python-dev python-pip git

2. Enable i2c by: sudo raspi-config and Interface Options > I2C > Enable And whilst you're in the config program, change your timezone Exit and reboot

3. Clone this repo and the BMP085 repo:

git clone https://github.com/andy-pi/weather-monitor.git
git clone https://github.com/adafruit/Adafruit_Python_BMP.git
cd Adafruit_Python_BMP
sudo python setup.py install

4. Install PIGPIO, a library for low level GPIO operations (this repo includes DHT22.py) (http://abyz.co.uk/rpi/pigpio/)

wget abyz.co.uk/rpi/pigpio/pigpio.zip
unzip pigpio.zip
cd PIGPIO
make
sudo make install

5. Turn on i2c: Run sudo raspi-config
   Use the down arrow to select 5 Interfacing Options
   Arrow down to P5 I2C
   Select yes when it asks you to enable I2C
   Use the right arrow to select the button
   Select yes when it asks to reboot

6. Install Python Slack Api wrapper:

sudo pip install slacker

7. Add your API keys to config.py

8. Update root crontab with the following lines to run the thingspeak script every 15 mins and slack update daily:

@reboot /usr/local/bin/pigpiod
@reboot sntp -s 24.56.178.140 # to force time update on reboot
0,15,30,45 * * * * python /home/pi/weather-monitor/thingspeak_update.py # for logging add >> /home/pi/weather-monitor/log 2>&1
30 6 * * * python /home/pi/weather-monitor/slack_update.py

Air Quality - Shinyei PPD42NS only

Basic Printout of air quality

Carry out steps 1-4 above and then:

sudo pigpiod
python air_quality.py

The output will be printed on screen. Note that the instantaneous AQI is not actually correct, it should be taken as a 24 average of the PM2.5 particles in micrograms/m3