Connect a normal LCD alarm so you can use HA to control blinds, lights, and radio upon alarm activation. Use deep sleep to allow battery operation on 2xAAA of the alarm clock.
- Alarm Clock with Beeper (in this case Lexon Flip with DCF77 RTC (i think)
- ESP32-C3 Microcontroller
- Low Pass Filter, in my case Resistor with 10 Ω & Capacitor (0.1 µF)
- Wire Up 3.3V and GND Pins of the ESP to the Battery. In my testing, the ESP32 even runs on 2xAAA Rechargeable Eneloops (2,4v).
- If unstable, use DC to DC converter to bring input voltage to 3,3/5v.
The low pass filter is to smooth the signal from the beeper for correct detection.
- Connect Beeper -> Resistor -> Capacitator -> GPIO0
In my case, the low pass filter prevented wakeup so i pulled a second wire. Also for this clock, the beeper always receives voltage so wakeup pin must inverted to trigger in ESPHome code.
- Connect Beeper -> GPIO3
- ESP is in Deep Sleep
- Alarm wakes it up
- Waits on definitive Alarm signal to trigger a sensor
- Reflects snooze with state reset
- Deep Sleep after 60s (in the future could be kept awake while beeping)
- Set alarm time as usual.
- Configure HomeAssistant to recognize the Sensor and execute actions.
- Power Management: ESP32 will sleep post-alarm, waking only for beeper signals. Just re-insert batteries if you want to trigger an ESP Boot.
With two AAA batteries (totaling approx. 3,000 mAh at 3.0V), the setup should last over a year on a single charge for the ESP alone.
- Active Mode: Consumes maybe 60mA-100mA; typically operational for 60 seconds daily.
- Deep Sleep Mode: Draws 5µA; active most of the day.