ESP8266 HomeKit Dual Lamps

Two lamps in one light fitting, controlled as one HomeKit accessory. The top lamp and the bottom lamp show up as two separate lights in the Home app, so you can switch each one on its own, and a button on the device steps through the combinations.

This is a test setup. The build uses two relay modules and no mains voltage, and was made to check the code and the hardware.

What it does

The accessory name gets the last three bytes of the MAC address added, for example Dual Lamp-A1B2C3, so several of them can live in one home.

Hardware

In this test setup the module is powered from the FTDI adapter, which is not recommended for long-term use. The lamps are the two lamps of one light fitting, lamp 1 on top and lamp 2 below. Only the relay modules are connected in the test build, with no mains voltage.

Wiring and pins

The Fritzing diagram at the top of this page shows the build on a breadboard, with the pinout of the module in the corner. The pins the firmware uses are set at the top of main.c:

The relays are switched active-high. Use an FTDI adapter set to 3.3 V, because a 5 V adapter can damage the module. The Fritzing source of the diagram is in the repository as Resources/dual_lights.fzz.

How the button and the lamps behave

After that the sequence repeats. Switching a lamp from the Home app updates the state, and the button then continues from there. When the state changes from the button, HomeKit is notified, so the Home app always shows what the lamps are doing.

Flash and install

The installation is the same as for the other ESP8266 HomeKit accessories on this site. The firmware runs on ESP-Open-RTOS with Life Cycle Manager 2, which sets up the WiFi and installs updates over the air. The full steps, from installing esptool to flashing, joining the LCM- WiFi network and pairing, are in ESP8266 HomeKit Blinds.

In the portal, use these values:

When the installation is done, scan the QR code the device generates in the Home app to add it.

Build from source

This repository includes the firmware source in the Dual_lamp folder: main.c, button.c and toggle.c. It builds with ESP-Open-RTOS. The Makefile uses the http-parser and dhcpserver extras, plus the wifi_config, cJSON, wolfssl and homekit components, with FLASH_SIZE set to 8, the dout flash mode at 40 MHz, and the HomeKit data stored at flash address 0x7A000.

The HomeKit setup code is set in main.c. Change it to your own before you use the device for real.

Firmware release

The release has a main.bin and a signature file, main.bin.sig.

Good to know

• This is a test setup and not a finished product.
• The HomeKit Accessory Protocol specification the firmware follows is the non-commercial version, for accessories you build yourself and do not distribute or sell.
• The repository is under the MIT licence.

Everything is in the ESP8266-HomeKit-Dual-Lamps repository on GitHub.