I programmed a Raspberry Pi 2 with Temperature, Light, Sound and Button Sensors to update a Google Sheet spreadsheet with the sensor data every minute. I also programmed the Raspberry Pi 2 to allow remote control of the LED, Buzzer and LCD Screen from a web browser over the internet.

The Google Sheet includes a realtime dashboard for visualising the sensor data in real time. The spreadsheet contains rules for triggering alerts (i.e. temperature too high). I will be notified of the alerts via SMS or an automated voice call using the Hoiio telephony service.

I used Grove sensors and actuators, connected to the GrovePi+ shield on a Raspberry Pi 2.

Here's the Google Sheet with dashboard (see tab "Dashboard") and sensor data (see tab "Data"): https://docs.google.com/spreadsheets/d/11WF-G47xkEBf5lIw16d9nWxNcBcUJdirGU-gg56f5Eo/edit?usp=sharing

Photo of the Raspberry Pi 2 with Grove sensors and actuators: https://github.com/lupyuen/iotapps/blob/master/raspberry_pi_setup.jpg

0. You'll need the following items:

   • http://www.seeedstudio.com/depot/Raspberry-Pi-2-Model-B-w-ARMv7-Quad-Core-1GB-RAM-p-2289.html
   • http://www.seeedstudio.com/depot/Quick-Starter-Kit-for-Raspberry-Pi-2-Model-B-p-2364.html
   • http://www.seeedstudio.com/depot/GrovePi-p-2241.html
   • http://www.seeedstudio.com/depot/Grove-Starter-Kit-for-Arduino-p-1855.html

1. Prepare the SD card with Raspbian: https://learn.adafruit.com/adafruit-raspberry-pi-lesson-1-preparing-and-sd-card-for-your-raspberry-pi

   I used the command: sudo ./install 2015-05-05-raspbian-wheezy.img

2. Configure the Pi: https://learn.adafruit.com/adafruits-raspberry-pi-lesson-2-first-time-configuration?view=all

3. Set up the network: https://learn.adafruit.com/adafruits-raspberry-pi-lesson-3-network-setup?view=all

4. Optionally, use a console cable: https://learn.adafruit.com/adafruits-raspberry-pi-lesson-5-using-a-console-cable?view=all

5. Set up SSH: https://learn.adafruit.com/adafruits-raspberry-pi-lesson-6-using-ssh?view=all

6. Set up VNC: https://learn.adafruit.com/adafruit-raspberry-pi-lesson-7-remote-control-with-vnc?view=all

7. Set up GrovePi: http://www.dexterindustries.com/GrovePi/get-started-with-the-grovepi/setting-software/

8. Copy /home/pi/GrovePi/Software/Python/grove_rgb_lcd/grove_rgb_lcd.py to /home/pi/GrovePi/Software/Python/

9. Download the Linux/ARM version of ngrok from https://ngrok.com/download and copy to /home/pi/GrovePi/Software/Python/

10. Grant execute access to ngrok:

    chmod +x /home/pi/GrovePi/Software/Python/ngrok
    

11. Download the following files to /home/pi/GrovePi/Software/Python/:

    • https://github.com/lupyuen/iotapps/blob/master/send_loop.sh
    • https://github.com/lupyuen/iotapps/blob/master/send_button_data.py
    • https://github.com/lupyuen/iotapps/blob/master/send_sensor_data.py
    • https://github.com/lupyuen/iotapps/blob/master/server.py

12. Connect the sensors/actuators to the following ports (photo here):

    • A0: Light sensor
    • A1: Temperature sensor
    • A2: Loudness sensor
    • D3: Button
    • D4: LED
    • D8: Buzzer
    • I2C-1: RGB LCD Backlight

13. Edit /home/pi/GrovePi/Software/Python/grove_temperature_sensor.py

    • Change “sensor = 0” to “sensor = 1"

14. Edit /home/pi/GrovePi/Software/Python/grove_loudness_sensor.py

    • Change "loudness_sensor = 0” to "loudness_sensor = 2"
    • Change "led = 5" to "led = 4"

15. Check that the sensors and actuators are working:

    cd /home/pi/GrovePi/Software/Python
    python grove_led_blink.py 
    python grove_buzzer.py
    python grove_button.py 
    python grove_light_sensor.py 
    python grove_temperature_sensor.py 
    python grove_sound_sensor.py 
    
    cd /home/pi/GrovePi/Software/Python/grove_rgb_lcd
    python example.py 
    python example2.py 
    

16. Create a Temboo account and download the Python SDK into /home/pi/GrovePi/Software/Python/temboo: http://support.temboo.com/entries/21388458-Using-the-Python-SDK

17. Create a Google App account and get the credentials (Client ID, Client Secret, Refresh Token, Access Token): https://temboo.com/library/Library/Google/Spreadsheets/

18. Create a new Temboo profile for adding new rows to the above Google Sheet, specifying the Google credentials (Client ID, Client Secret, Refresh Token, Access Token), spreadsheet key, worksheet ID: https://temboo.com/library/Library/Google/Spreadsheets/AddListRows/

19. Edit send_loop.sh, send_sensor_data.py, send_button_data.py and update the ngrok and Temboo settings accordingly

20. Run send_loop.sh, which calls send_sensor_data.py to get the sensor data and send to Google Sheets via Temboo

21. send_loop.sh calls send_button_data.py to poll the button state repeatedly and update Google Sheets when the button is pressed or released

22. send_loop.sh also starts server.py, a local Python web server that controls actuators: LED, LCD screen, buzzer

23. To control the actuators remotely via a web browser, send_loop.sh uses ngrok to redirect internet requests to the local Python web server (server.py):

    ./ngrok http --log "stdout" -config=/home/pi/.ngrok2/ngrok.yml --subdomain=YOURSUBDOMAIN 80 &
    

24. The actuators may be controlled remotely as follows:

    • Switch on LED: http://luppypi.ngrok.io/led_on
    • Switch off LED: http://luppypi.ngrok.io/led_off
    • Buzz the buzzer: http://luppypi.ngrok.io/buzz
    • Show a message on the LCD screen: http://luppypi.ngrok.io/lcd/hello%20from%20github

25. send_loop.sh uses ngrok to expose the Raspberry Pi's SSH port to the internet:

    ./ngrok tcp --log "stdout" -config=/home/pi/.ngrok2/ngrok.yml --remote-addr=YOURHOST.tcp.ngrok.io:YOURPORT 22 &
    

    So to connect to the Raspberry Pi via SSH from anywhere in the internet, you only need to use:

    ssh YOURHOST.tcp.ngrok.io -p YOURPORT -l pi
    

26. To start send_loop.sh automatically upon reboot, run

    sudo crontab -e
    

    and append the line

    @reboot /home/pi/GrovePi/Software/Python/send_loop.sh > /home/pi/send_loop.log &
    

27. To enable the crontab log, see http://raspberrypi.stackexchange.com/questions/3741/where-do-cron-error-message-go

28. For info, warning and error messages by send_loop.sh, see /home/pi/send_loop.log

29. Disable the graphical desktop shell to save power: http://ask.xmodulo.com/disable-desktop-gui-raspberry-pi.html

30. Remember to backup your Raspberry Pi SD card: http://computers.tutsplus.com/articles/how-to-clone-raspberry-pi-sd-cards-using-the-command-line-in-os-x--mac-59911

31. Alerts: I implemented Alerts using simple Google Sheet formulas. If you click on the “Alert” heading in Column G, you’ll see a formula that checks whether the temperature is too hot (above 31 degrees) and if so, shows the message “Warning: Too hot!”. The “Alerts” tab shows all rows with alerts.

32. Notifications: In the “Alerts” tab you can see that when there is an alert generated, the system will make an automated voice call (or SMS). This is done with a Google App Script connected to Hoiio, the SMS and Voice Telephony service. Pressing the button sensor also triggers a voice call or SMS. Hoiio offers a free trial with limited messages.