Eeasterhegg 2024 Badge as Homeassistant Indicator Light

• Control the brightness and activity of the beautiful EH2024 Badge via Homeassistant
  • which means, controlling it via esphome from an ESP module
  • which means, controlling it's supply voltage

• The badge takes 3V and about 200mA of power
• It still works with about 1.8V where it takes about 50mA but has almost no activity and is very dark
• which is perfect, so we can control it's activity by controlling it's supply voltage

Basically we want to trick the step-down module to generate less output by changing the feedback voltage it sees by generating an offset voltage using the ESP32's DAC.

1. To do that, we use a common StepDown module and connect it's Vin and GND to 5V and GND of an ESP32
2. We use the poti on the StepDown module to set it's output to slightly above 3V
3. We solder an extra pin to the module, onto the FB pin of the the modules step-down IC
4. via at least 10k of R we connect that FB pin to the ESP32's DAC
5. for fun, we also connect the Step-Down Modules Vout to an ADC pin of the ESP32
6. let's make sure the DAC output is 0V and re-measure the Step-Down Output and re-adjust it's poti so the output is exactly 3V (or a bit more if you want it brighter)
7. Flash the ESP32 with esphome
8. we are done

• ESPhome Example YAML
• Helpful Document explaining different options of controlling power supply voltage

Badge controllable via HomeAssistant.