Achim Pieters Offers a Step-by-Step Guide to Building a Low-Cost Apple HomeKit-Compatible LED Light


Hobbyist and maker Achim Pieters has written a guide for those looking to roll their own LED lighting under Apple HomeKit control, using “three ‘standard’ modules” available at a very low cost.

“I have already written several blogs about [using] ESP HomeKit,” Pieters writes by way of introduction. “For the more experienced makers this is not a problem. But for starters or starting makers or hobbyists it may not be so easy. That’s why in this blog I’m going to make a LED strip using three ‘standard’ modules. This should make it possible for everyone to make their own Homekit LED strip.”

Pieters’ guide centers around the FreeRTOS-based ESP-Open-RTOS, a community effort to bring compatibility with the Apple HomeKit accessory standard to Espressif ESP-based microcontrollers — not to be confused with Espressif’s own HomeKit Software Development Kit, which is available only to those enrolled in Apple’s mFI Program.

The “three ‘standard’ modules” used by Pieters in the tutorial are an Espressif ESP8266-01S microcontroller module, an SRD-05VDC-SL-C relay, and an MP2307 DC-DC buck converter — plus, of course, the LED strip to be controlled. “The LED strip can in principle be any strip, except for a color LED strip, because in this case we only have an on and off switch,” Pieters explains. “In this example we use a 12 Volt white LED strip, also suitable for outdoor use, IP67 certified.”

The wiring for the project is relatively simple: A 12V supply goes into the buck converter and the common leg of the relay; the normally-open leg goes to the LED strip. The output from the buck converter, meanwhile, powers the ESP8266 module, which in turn is connected to the relay to toggle it on and off — and thus control the LED lighting strip.

On the software side, Pieters’ approach makes use of Life Cycle Manager (LCM), a tool created by pseudonymous programmer “HomeAccessoryKid” that handles the initial installation, Wi-Fi network configuration, and over-the-air (OTA) firmware upgrades for ESP-Open-RTOS — improving the maintainability over a flash-and-forget approach, which could leave insecure or otherwise outdated code running on your home network without oversight.

Pieters’ full write-up is available on Instructables, including pre-compiled binaries.