Smart AC Unit

by littleBits July 15, 2014

Monitor and control the temperature of your home remotely. 

Turn your AC window unit into a smart internet-connected device. Forget to turn the AC off? No problem, just press a button on your phone to turn it off! Cool down your apartment on the way home from work? Easy! Use the IFTTT location channel to automatically turn on your AC when you enter a geographic area. Save energy and save $$$ with this easy DIY project.

*Note: The AC Switch, IR transmitter, and temperature sensor are coming soon. Stay tuned!

How it works:

Monitor - the temperature sensor transmits data through the cloudBit to Cloud Control, which can be viewed under the “receive signal” tab. This way, you can always know temperature in your apartment/house.

Control - Use Cloud Control to turn your AC unit on or off using the IR transmitter and the AC switch. When you press the button in Cloud Control, you send a signal to the cloudBit in your home. This signal is passed on to the IR transmitter, which outputs out a burst infrared light. You won’t be able to see this burst of light because the IR spectrum is not visible to the human eye. It's the same control technology as used in your television's remote control.

The AC switch is plugged into the outlet, and the window unit is plugged into the AC switch. The AC switch has an infrared sensor that pairs with the IR Transmitter. The AC Switch toggles the window unit’s power on and off whenever it receives a burst of of infrared light from the IR transmitter. When you send a signal from your phone to the cloudBit, the window unit will turn on/off. *Note: your IR Transmitter should be positioned in the vicinity the AC switch to ensure that it receives the control signal.

Automate - Use IFTTT to automatically turn your AC unit on/off in response to conditions that you set. IFTTT (If This Then That) is a service that lets you connect to different web apps through simple conditional statements. Use the Date & Time channel to turn your AC on at 5pm and off at 8pm, text “cool it down” as you walk home from work with IFTTT’s SMS channel, or create a location based trigger that turns on your AC unit when you enter your home zone.

Bits used: cloudBit™, IR Transmitter, temperature sensor, usb power

Tags: Wi-Fi Gadgets Hack Around the house

Videos and Recipes

IFTTT Recipe: If I send IFTTT a text tagged #AC, then turn on my Air Conditioner connects sms to littlebits


  1. 1

    Set up your cloudBits if you haven’t done so already. Instructions for setting up the cloudBit can be found here.

  2. 2

    Connect your circuit: USB power + temperature sensor + cloudBit + IR transmitter. We held our circuit together with littleBits mounting board and mounted the mounting board to the wall near the window unit.

  3. 3

    Plug it in! Plug the AC Switch into the wall. Then plug your window unit into the AC switch. You will notice that the AC switch has a small oval-shaped sensor on it. You should position this sensor so that there is a direct line of sight between it and the IR transmitter on your littleBits circuit.

    When activated through the cloudBit, the IR trigger sends a burst of IR light (which is invisible to the eye) to the AC Switch, which will turn your window unit either on or off.

Bits used (4)

Other Materials Used (3)

  • littleBits AC Switch 1
  • littleBits Mounting Board 1
  • VHB Tape 1

Other files

  • phatbhuda 3 months ago

    This is neat, but what I'd really like is the ability to use the IR Transmitter to send IR remote control signals to my AC unit. Paired with the Arduino bit this should be easily doable.

  • monkycl 3 months ago

    Hi, can it work with another IR switch like that?

    • littleBits 3 months ago

      Our IR transmitter is programmed to our own AC switch, so it won't work out of the box with other remote control devices.

  • mzamkow about 1 month ago

    Will the IR transmitter be programmable to send different messages? I'd love to be able to pair it with a cloudBit to cloudify all my devices that already have IR sensors built in (TV, stereo, etc)

    • emily_littlebits about 1 month ago

      The forthcoming IR transmitter is not re-programmable. It is currently configured to work only with our AC switch and the remote trigger module. Perhaps this will be possible in a future version though :)

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