Project Duration:
July 2021 – May 2022
When I built my super-bright Möbius strip light, I had difficulty finding a suitable dimmer. These devices work by switching the light rapidly on and off. While the switching is invisible to the human eye, they would introduce an annoying high-pitched noise in the power supply. Increasing the dimmer’s switching frequency to over 20 kHz, well above human hearing, could solve this problem. Unfortunately, most dimmers on the market only operate at about 500 Hz. This led to the design and manufacture of my custom LED dimmer PCB.
Design and Features
The dimmer is built around an ESP32 microcontroller module with built-in Wi-Fi and Bluetooth capabilities. It can dim two channels, each capable of supporting up to 36V and 15A. It is ideal for controlling high-power lights with warm and cold white LEDs to adjust color temperature and brightness. A standard high-power supply powers the LEDs. However, they buzz when only a low current is drawn, which is an issue when the dimmer is on standby. My design avoids this with a built-in mains power supply (100 – 240 V AC) independent of the LED’s power supply. An integrated relay on the board activates the LED power supply only when needed, helping to save energy. Another feature is the compatibility with the Adafruit Feather standard. It lets it quickly extend the board’s capabilities with modules like displays and extra relays. Finally, the Wi-Fi-enabled board is configurable through the ESPHome framework. The dimmer integrates seamlessly with the home automation system Home Assistant, making it easy to control with various remotes and automations.
Process
This project was my first PCB design, from concept to a working product. For the design, I used the industry-standard software Altium Designer. The project was challenging and required a few revisions of the PCB. However, the dimmer finally works perfectly and controls my Möbius strip light today.
