ESP8266 HomeKit Fountain Light

A HomeKit controller for a garden water feature: it lights the fountain with a ring of colour-changing LEDs and switches the pond pump, both from the Home app. It runs on a printed circuit board that was designed for the job.

The project started when an old stone water feature was given to the author. It looked like the chance to put everything learned into practice in one build: the software, the hardware design in KiCad, making a printed circuit board, having it produced, testing it, and then using it for real. It worked.

High voltage and water

What it does

The accessory shows up as WATER FOUNTAIN with the chip ID added to its name, and it has an OTA trigger characteristic for the updates.

Hardware

The LED ring

The light is a ring of 16 NeoPixel LEDs on a round white board. To make it survive outdoors, the ring is cast in a waterproof synthetic resin, and it is mounted in the stone water feature, in the clear dish on top, where it lights the water.

Designing the board in KiCad

The controller is a custom board, drawn in KiCad. The repository has the whole KiCad project, called ESP Base, with the schematic, the board layout, and the parts it needed: a relay footprint and 3D models of the HLK-PM power modules. The gerber files, which is what a board maker needs, are in the repository too, in a folder and as a gerber.rar.

Building it

The boards were produced, and here is a stack of the bare boards. The board has a warning triangle at the high voltage part.

Assembly started with the ESP-12 module and its small parts.

On the mains side sit the HLK-PM01 power module, the fuse holder with its fuse and the blue screw terminals.

The finished board fits in a plastic junction box.

Testing and using it

The board was tested on the bench with the ring connected. The project checklist in the repository shows every stage as done: a new NeoPixel ring, beta testing the software, making and ordering the printed circuit board, beta testing the board, hardware installation, a proof-of-concept film and an end result film, and releasing the KiCad and gerber files.

The films of this project, and of many others, are on the StudioPieters YouTube channel.

Pins

These come from the firmware source in the fountain folder of the repository. The relay is switched active-high.

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.

Firmware releases

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

Good to know

• 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. The HomeKit setup code is set in the firmware source, so change it to your own.

Everything is in the ESP8266-HomeKit-Fountain-light repository on GitHub.