Smart-dimmed theatrical LED fixture
Four stage-lighting fixtures with my own constant-current driver and ESPHome control board, built to dim smoothly to 0.1% without flicker on phone cameras.
This started as a 0–10 V dimming controller for an off-the-shelf LED driver. I’m now designing the constant-current driver myself instead, which drops both the commercial driver and the 0–10 V interface.
Requirements
- Smooth dimming from full output down to 0.1%.
- No visible flicker on phone cameras, including slow-motion video.
- Several fixtures that can be set to the same level together.
Architecture
The design is split across two boards fed by an off-the-shelf isolated AC-DC module:
- Driver board. A tracking buck converter feeds three linear current sinks in parallel, each with its own shunt for a different current range. Linear regulation keeps the output ripple-free, and the buck tracks the LED’s forward voltage so the sinks don’t burn excess power. Only the very bottom decade, below 1 mA, uses PWM on the low-range channel.
- Control board. An ESP32 running ESPHome reads a rotary encoder for level and a second button that syncs multiple units.
Both boards are custom PCBs designed for manufacture at JLCPCB.