Miriam Lauter - Make your own Smart Air Conditioner

MAKE YOUR OWN SMART AIR CONDITIONER Created by / Miriam
Lauter @miriamlauter

THE GOAL

OVERVIEW Getting Started Hardware A simple Flask application The code
on the Pi Final Notes and Demo!

OVERVIEW Getting Started What you'll need Resources Cost Hardware A
simple Flask application The code on the Pi Final Notes and Demo!

WHAT YOU'LL NEED

ADAFRUIT.COM (Credit: Allie Brosh)

AN AIR CONDITIONER window unit connects to AC power draws
less than 15 amps you don't care about it that much

A RASPBERRY PI (Photo: Raspberry Pi Foundation)

EXTRA RASPBERRY PI COMPONENTS + (or whatever fits your R-Pi
model) Micro USB charger wall adapter Micro SD card USB wifi (Photos: adafruit.com) mlauter.github.io/getting-started-with-raspberry-pi

MOAR STUFF Male and female jumper wires Prototype PCB Paper
Power Switch (relay) Digital temperature sensor 4.7K resistor

TOOLS! Soldering iron and solder Very skinny phillips head screwdriver
Hot glue gun

FOR TESTING/DEBUGGING ONLY A breadboard An LED Multimeter - nice
to have but not necessary

OVERVIEW Getting Started Hardware Controlling the AC with the raspberry
pi Measuring temperature with the raspberry pi A simple Flask application The code on the Pi Final Notes and Demo!

TWO SIMPLE CIRCUITS

Allow the Raspberry Pi to turn the air conditioner on
and off #1 RASPBERRY PI | RELAY | AIR CONDITIONER

CONNECT THE RASPBERRY PI Make sure the pi is not
plugged in Find a GPIO (general purpose input output) pin Don't use GPIO4 (we'll need it later)

WHILE YOU'RE TESTING

Allow the Raspberry Pi to check temperature in your room
#2 DIGITAL TEMPERATURE SENSOR

SOLDERED TO PCB PROTOTYPE

OVERVIEW Getting Started Hardware A simple Flask application Overview Intro
to Flask 3 Routes Translating states The code on the Pi Final Notes and Demo!

APPLICATION REQUIREMENTS Raspberry Pi can: 1. Give information about room
conditions 2. Receive instructions User can: 1. Receive info about room conditions 2. Give instructions Store information to be passed between User and R-Pi

FLASK Flask is a microframework for Python based on Werkzeug,
Jinja 2 and good intentions.

FLASK RESOURCES and video series Miguel Grinberg's Flask Mega-Tutorial Real
Python's Flask tutorial 'Discover Flask'

FLASK BASICS $ mkdir app $ mkdir app/assets $ mkdir
app/templates $ touch app.py $ cd app $ tree . ├── app.py ├── assets └── templates └── index.html

APP.PY: HELLO WORLD from flask import Flask, render_template app =
Flask(__name__) @app.route("/") def hello(): return render_template('index.html', name='Miriam') if __name__ == "__main__": app.run()

@ROUTE DECORATORS @app.route("/") #route(rule, **options) def hello(): return render_template('index.html', name='Miriam')
Add the following url rule: when there is a request from a url like my.site.com/ run the hello function. If you are testing you'll be running on localhost:5000

JINJA TEMPLATES

AN EXAMPLE TEMPLATE # index.html <html> <head> <title>Air conditioner remote</title>
</head> <body> <h1>Hello World</h1> <div> Hello, {{name}} </div> </body> </html>

DEBUG MODE app.run(debug=True)

3 ENDPOINTS Homepage (GET) User Endpoint (POST) Pi Endpoint (POST)

ENDPOINT 1: HOMEPAGE from flask import Flask, render_template app =
Flask(__name__) @app.route('/', methods = ['GET']) @app.route('/index', methods = ['GET']) def homepage(): data = #Get stored room temp and AC state return render_template('index.html', data=data)

TRANSLATING STATES

ENDPOINT 2: USER @app.route('/user', methods=['POST']) def user(): user_input = request.json
current_temp = #Get most recently stored room temp desired_state = translate_state(user_input, current_temp) # Store the desired_state

ENDPOINT 3: PI @app.route('/pi', methods=['POST']) def pi(): pi_input = request.json
#store pi input #return ON or OFF return flask.jsonify(desired_state)

OVERVIEW Getting Started Hardware A simple Flask application The code
on the Pi RPi.GPIO Surviving unresponsive server Final Notes and Demo!

THE CODE ON THE RASPBERRY PI 1. Make requests using
the Pi endpoint 2. Set the switch pin high (on) or low (off) 3. Repeat

MAKING REQUESTS

import requests import json url = 'your.url.here/pi' data = {'info
to send'} headers = {'Content-type': 'application/json', 'Accept': 'text/plain'} r = requests.post(url, data=json.dumps(data), headers) # 0 or 1

SETTING THE SWITCH PIN

RPI.GPIO import RPi.GPIO as io io.setmode(io.BCM) switch_pin = 17 io.setup(switch_pin,
io.OUT) io.output(switch_pin, False) def is_running(): return io.input(switch_pin)

AND NOW FOR THE REAL MAGIC...

def turn_on(): io.output('switch_pin', True) def turn_off(): io.output('switch_pin', False) r =
requests.post(url, data=json.dumps(data), headers) # 0 or 1 if r == 1: turn_on() else: turn_off()

NOW DO THIS OVER AND OVER AGAIN

WHAT IF THE SERVER DOESN'T RESPOND?

WHILE TRUE:

FINAL NOTES

SECURITY Input validation Web form Raspberry Pi endpoint Login required
decorators

THE END - Blog: - Github: mlauter.github.io /mlauter

Miriam Lauter - Make your own Smart Air Conditioner

Miriam Lauter - Make your own Smart Air Conditioner

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