arduino | The Ostrich

A/C Control Project: Bringing it all Together

By Itamar Ostricher Friday, October 4, 2013 4 Make arduino, automation, home-control, iot A/C Control Project Permalink 1

I have central air-conditioning in my apartment. It’s controlled by a remote, using IR signals to send commands to the A/C control unit.

As any decent geek would, I’d like to be able to control my A/C using other means (e.g., a smartphone).

In previous posts, I went into great detail on specific aspects of this project, like using an Arduino to decode and send A/C commands, and recognizing A/C beeps for feedback.

The last part in the puzzle is making all the pieces play nice with each other, and finally accomplish the intended goal – Controlling the A/C at home with the smartphone from anywhere over the Internet!

How was that accomplished?

An always-on computer in the apartment is running a web server accessible from the Internet, serving an “A/C-control site” (screenshot above from Android smartphone). The site is developed with the Django web framework and Bootstrap front-end framework.

The controls in the web-app are associated with server-side Python functions, that pass the parameters to an RPC server that talks with the Arduino that is connected to its USB port.

The RPC server uses the Arduino to send commands to the A/C based on the parameters it received from the web-app, and uses the microphone to verify that the commands were transmitted successfully.

As usual, the rest of this post provides in-depth description of what I’ve done. The actual projects are available on GitHub (web-app project, and RPC-server project) for anyone to fork, clone, tinker and use.

Controlling My A/C With an Arduino

By Itamar Ostricher Saturday, September 14, 2013 15 Make arduino, automation, home-control A/C Control Project Permalink 0

I have central air-conditioning in my apartment, and it’s controlled by a remote, employing IR signals to send commands to the A/C control unit.

As any decent geek would, I’d like to be able to control my A/C using other means (e.g., a smartphone).

In a previous post, I went into detail about reverse engineering the remote. Now it’s time to proceed to actually using these powers to replace the original A/C remote with my own Arduino-controlled thingie!

The gist: using an Arduino Uno board with a IR-LED circuit (see below), along with Ken Shirriff’s Arduino IRremote library (slightly modified), I was able to transmit the A/C commands that were analyzed in the previous post in lieu of the original remote.

: Arduino IR Transmitter Circuit

Keep reading for a full drill down, or jump straight into my home-control-arduino GitHub project for the actual code and documentation.

Using an Arduino to Reverse Engineer My A/C Remote

By Itamar Ostricher Saturday, September 14, 2013 31 Make arduino, automation, home-control A/C Control Project Permalink 0

I have central air-conditioning in my apartment, and it’s controlled by a remote, employing IR signals to send commands to the A/C control unit.

As any decent geek would, I’d like to be able to control my A/C using other means (e.g., a smartphone).

Towards that goal, I figured I should first reverse engineer the IR commands the remote sends to the A/C, so I could later send these commands using other methods.

The gist: using an Arduino Uno board with a Phototransistor circuit (see below), I was able to obtain the IR waveform using Ken Shirriff’s Arduino IRremote library (slightly modified), and even graph these waveforms with Python’s matplotlib, as shown below.