Turn Raspberry Pi into weather station with DHT22 sensor and OpenWeatherMap.org

Live example located in Szczecin, Poland can be found here: http://weather.spychalski.info/

Blog: http://shtr.eu/

#Electrical diagram

• Raspberry Pi
• pigpio library installed
• DHT22 temperature and humidity sensor
• BMP180 (or BMP085) I2C pressure sensor
• python
• php5 with SQLite3 enabled
• SQLite3
• I2C enabled Raspberry Pi Raspbian distribution
• any web server: nginx recomended

• Do electrical stuff like showed on diagram. It's really simple
• Enable I2C in your Raspberry Pi. You can use example from instructables
• Install Adafruit BMP Python library

sudo apt-get update
sudo apt-get install git build-essential python-dev python-smbus
git clone https://github.com/adafruit/Adafruit_Python_BMP.git
cd Adafruit_Python_BMP
sudo python setup.py install

• install pigpio library

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

• pigpio has to be running as a service, so add sudo /home/pi/PIGPIO/pigpiod to /etc/rc.local
• check if you have SQLite3 PHP library. If not, or not sure, install it sudo apt-get install php5-sqlite
• check if you have nginx+php. If not, or not sure, install it sudo apt-get install nginx php5-fpm php-apc
• clone this repository git clone git@github.com:DzikuVx/WeatherStation.git
• cd WeatherStation
• get all submodules while inside repository root folder: ** git submodule init ** git submodule update
• check if sensors are working python get_data.py
• configure Raspberry Pi web server, example configuration for nginx, PHP5-FMP and domain http://weather.spychalski.info included below
• that's all

#Configuration

To configure WeatherStation to work with OpenWeatherMap you need to set some data in a few places.

For example, to get data for Szczecin, Poland you need to:

• register at http://openweathermap.org/
• get your API key
• edit website/config.inc.php and set $config['cityId'] = 3083829;. Of course, 3083829 is city ID for Szczecin, Poland. For any other city you need to set other ID (but this is obvious).
• replace openweatherconfig.py template with

config = {
    'user': 'DzikuVx',
    'password': 'you_would_like_to_know',
    'api': 'yes_you_do_want_to_have_own_api_key',
    'location': 'Szczecin,PL',
    'coords': 'lat=53.48&long=14.40&alt=100'
}

#Crontab

To serve its purpose, WeatherStation need to collect data on regular basis. That's why you need to configure some crontab jobs (crontab -e):

• Collect data from sensor */20 * * * * sudo python /home/pi/WeatherStation/get_data.py
• Collect from OpenWeatherMap.org (current pressure and wind) */20 * * * * python /home/pi/WeatherStation/get_external_data.py
• Upload data to OpenWeatherMap.org (because we like to share, don't we?) */30 * * * * python /home/pi/WeatherStation/upload_data.py
• For best webpage performance, prefetch forecast and history */30 * * * * wget http://weather.spychalski.info/cron.php

server {
  listen 0.0.0.0:80;

  server_name weather.spychalski.info;

  access_log off;

  root /home/pi/raspberry_temperature_log/website;
  index index.php;

  # default try order
  location / {
    try_files $uri $uri/ /index.php?$args;
  }

  # enable php
  location ~ \.php$ {
    fastcgi_pass unix:/var/run/php5-fpm.sock;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    include fastcgi_params;
  }
}

#Screenhoths

##Sensor ##Sensor