Smart Lighting App

Smart Lighting App is an IoT app designed to control home lighting from multiple inputs. The app provides several methods for switching on/off lighting, through manual and automated processes. The app runs on a Raspberry Pi and for prototyping purposes, an LED will be used to simulate the lighting.

Four methods the LED can be switched on/off:

• Tactile on/off button
• Virtual on/off button (hosted on Flask server)
• LED switches on/off in accordance with sunset/sunrise
• MQTT Protocol

Tactile button:

A tactile button is wired up to the Raspberry Pi. When the button is pressed, the state of the LED is changed through button.py.

Virtual button:

A Flask server running on the Raspberry Pi hosts index.html which contains a light bulb image. When the image is clicked on, AJAX routes to led_toggle which sends a HTTP POST request to change the state of the LED.

Sunset/Sunrise:

The time of the sunrise and sunset are found using Sunwait. Cron jobs are used to monitor when the sun has risen or set.

crontab entries:

*/5 * * * * sunwait sun up 51.886661N 8.618732W ; python /home/pi/development/smart-lighting-app/light_on.py
*/5 * * * * sunwait sun down 51.886661N 8.618732W ; python /home/pi/development/smart-lighting-app/light_off.py

MQTT:

An MQTT broker can be used to change the state of the LED.

With led_sub.py running on the Pi, an MQTT payload can be published from any device with an ON or OFF message. The MQTT broker sends this to the subscriber (the Pi) which in turn switches the LED on/off.

Technologies

• Raspberry Pi 3 Model B+, LED, tactile button
• HTTP, MQTT
• Flask
• Sunwait
• HTML, CSS, AJAX, Python
• Cron

Usage

(Note: Aside from the cronjob for changing the LED state, the other three methods must be run independently and do not function simultaneously.)

Ensure the Pi circuit is wired correctly:

• Button is wired to pin 22
• LED is wired to pin 18

# Clone the repository:
$ git clone https://github.com/TonyN96/smart-lighting-app.git

# Go into the repository
cd smart-lighting-app

Tactile button:

Run the button.py file

python button.py

Virtual button:

Run the app.py file to run the Flask server

python app.py

Visit localhost:4000

MQTT:

Run led_sub.py file with your MQTT broker URL

python led_sub.py mqtt://broker.hivemq.com:1883/YOUR_ID/home

Publish to the MQTT broker with ON or OFF as message payload. This can be done from another device, or led_pub.py can be used in a new terminal. Replace URL with your broker URL and replace MESSAGE with ON or OFF.

python leb_pub.py mqtt://broker.hivemq.com:1883/YOUR_ID/home MESSAGE