Convert a traditional air conditioning system into a smart one and control it from your smartphone.

In this DIY guide, we will build a Wi-Fi-based IR controller to convert a traditional air conditioning system into a smart AC. By building this tiny controller, you will be able to control your traditional HVACs or air conditioner units using your smartphone with an intuitive climate control interface that allows you to turn the HVAC on/off and change the temperature, fan speed, modes, etc. with just a tap.

It also shows you the real-time temperature inside and outside the room from the ADC sensors installed in your AC unit. By making your traditional AC smart, you can conveniently control the AC unit, add automation, save energy, and increase its lifespan.

To compile and build the firmware, you need to install the ESPHome add-on in Home Assistant. Then follow these steps:

Now make the following changes in the code:

For instance, change to platform: lg for LG AC. You can refer to the IR Remote Climate documentation for more details.

After making the required changes, click Save and then click Install. Plug the NodeMCU or D1 Mini into your PC using a micro USB cable and select the Plug into this computer option. This will start compiling the firmware.

Once compiled, click Download. Save the downloaded smartac-factory.bin firmware file in the Desktop or Downloads folder.

Once the firmware is downloaded, you may click Open ESPHome web and do the following:

After the firmware is flashed, the device should be online.

In the Home Assistant (HA), you can now add and control the wireless IR remote. The steps are as follows:

This will add the smart AC controls on the dashboard. Next, you can connect the NodeMCU or D1 mini with the IR transmitter and receiver to start controlling your AC through your smartphone.

Refer to the following diagram to solder the IR LED, receiver sensor, and transistor on a PCB. If you've never soldered before, learn how to solder.

You can use a berg strip and jumper wires to connect the IR transmitter and receiver Vcc, GND, and Data In/Out pins to the NodeMCU or D1 Mini.

The result may not look good on the first attempt. However, you can improvise later. You can print a 3D case using a 3D printer to enclose all hardware. Alternatively, you may also buy a cheap IR blaster and flash the smartac-factory.bin firmware on it. Check out our complete guide to convert a cheap IR blaster and integrate it with Home Assistant.

You may now connect the USB cable to the device to power it on and use the climate control component added to your Home Assistant dashboard to control your traditional HVAC wirelessly.

You may download and install the Home Assistant app on your iOS device or Android smartphone to control your HVACs, add automation, etc. For instance, you can set up an automation where the HVAC will turn on automatically when your presence is detected in the room and switch off as soon as you leave the room. For this, you can use an ESP32 board to build a presence detection sensor for HA, allowing you to trigger automation based on your presence.

If you own an iOS device (i.e. iPhone or iPad), you may also add this DIY smart IR climate controller to your HomeKit setup and control your HVACs using the HomeKit interface instead of Home Assistant.

The HomeKit UI is much more intuitive, and so recommended for iOS users. All you need to do is install HomeKit integration in Home Assistant to broadcast it as a HomeKit bridge; you can then control your smart devices in Home Assistant, including the IR AC controller, from the HomeKit app on iPhone or iPad.

By following this step-by-step guide, you will be able to create a Wi-Fi-based IR controller to make any standard AC system smart. You can then control your traditional HVACs or air conditioner units using your smartphone, to turn them on/off and change the temperature, fan speed, and more. This should help you save energy and stay cool this summer!

Ravi is an expert tech explainer, an IoT enthusiast and Linux lover with a background in big data and app development. He spends most of his weekends working with IoT devices and playing games on the Xbox. He is also a solo traveler who loves hiking and exploring new trails.

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