Features:

• Automatic switching between 2 optical audio inputs → 1 optical output
• Works with TOSLINK / SPDIF signals
• Signal presence detection based on frequency measurement
• Configurable per channel:
  • Frequency threshold
  • Minimum active time before switching

• Anti-flicker logic to prevent rapid toggling
• ESPHome-based firmware with OTA updates
• Live configuration via:
  • Home Assistant
  • Integrated web interface

• No SPDIF decoding or audio processing required
• Supports S/PDIF clock rate up to 16 MHz
• Power Supply via USB-C
• Compact enclosure made from 3D-printed parts

Web Interface:

How It Works:

Each optical input is converted into a digital pulse signal using a standard TOSLINK receiver module.  
The ESP32 continuously monitors both inputs and evaluates their activity:

1. Incoming SPDIF signals are frequency-divided (division by 4096) to a measurable range  
2. The ESP32 counts pulses to determine signal activity  
3. If an input stays above a configurable frequency threshold for a defined time:
   - Channel A → Switch OFF
   - Channel B → Switch ON
4. Once switched, the system waits until the signal drops below the threshold before re-arming