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BTHome for ESPHome

2-Gang Switch

A battery-efficient dual switch using nRF52 that broadcasts both switch states via BTHome. Uses a shared wakeup pin so either switch can wake the device from deep sleep.

Hardware

Section titled “Hardware”
  • Seeed XIAO BLE (nRF52840)
  • 2x Toggle switches or rocker switches
  • 2x 1N4148 diodes (for wakeup OR circuit)
  • 3.7V LiPo battery

Wiring

Section titled “Wiring”
ComponentXIAO Pin
Switch 1D2 → GND
Switch 2D3 → GND
Wakeup (combined)D4
Battery+BAT+
Battery-BAT-

Wiring Diagram

Section titled “Wiring Diagram”
graph TD
    subgraph XIAO["Seeed XIAO BLE"]
        D2["D2 (Pin 2)"]
        D3["D3 (Pin 3)"]
        D4["D4 (Pin 4)"]
        V3["3V3"]
        GND["GND"]
    end

    subgraph Switches
        SW1["Switch 1"]
        SW2["Switch 2"]
    end

    subgraph Battery["LiPo Battery"]
        BATP["BAT+"]
        BATN["BAT-"]
    end

    SW1 --- D2
    SW1 --- GND
    SW2 --- D3
    SW2 --- GND

Wakeup Circuit

Section titled “Wakeup Circuit”

Wire both switch outputs to the wakeup pin using diodes to create an OR gate:

graph LR
    subgraph Wakeup["Diode OR Gate"]
        D2["D2<br/>(Switch 1)"] --> DIODE1["1N4148<br/>▶|"]
        D3["D3<br/>(Switch 2)"] --> DIODE2["1N4148<br/>▶|"]
        DIODE1 --> D4["D4<br/>(Wakeup)"]
        DIODE2 --> D4
        D4 --> R["10kΩ"]
        R --> V3["3V3"]
    end

    style D4 fill:#f96,stroke:#333
    style DIODE1 fill:#fff,stroke:#333
    style DIODE2 fill:#fff,stroke:#333

When either switch is pressed (pulls to GND), D4 goes LOW and wakes the device.

Configuration

Section titled “Configuration”
esphome:
  name: switch-2gang
  friendly_name: 2-Gang Switch


nrf52:
  board: xiao_ble
  bootloader: adafruit


logger:


external_components:
  - source:
      type: git
      url: https://github.com/dz0ny/esphome-bthome
      ref: main
    components: [bthome]


# Battery monitoring
sensor:
  - platform: adc
    pin: 29
    id: battery_voltage
    name: "Battery Voltage"
    update_interval: 60s
    filters:
      - multiply: 2.0


  - platform: template
    id: battery_percent
    name: "Battery"
    unit_of_measurement: "%"
    lambda: |-
      float voltage = id(battery_voltage).state;
      float percent = (voltage - 3.0) / (4.2 - 3.0) * 100.0;
      if (percent > 100) percent = 100;
      if (percent < 0) percent = 0;
      return percent;
    update_interval: 60s


# Switches on separate pins for individual state reading
binary_sensor:
  - platform: gpio
    pin:
      number: 2
      mode: INPUT_PULLUP
    id: switch_1
    name: "Switch 1"
    filters:
      - invert:
      - delayed_on: 10ms
      - delayed_off: 10ms


  - platform: gpio
    pin:
      number: 3
      mode: INPUT_PULLUP
    id: switch_2
    name: "Switch 2"
    filters:
      - invert:
      - delayed_on: 10ms
      - delayed_off: 10ms


# BTHome broadcast
bthome:
  min_interval: 5s
  max_interval: 30s
  tx_power: 4
  sensors:
    - type: battery
      id: battery_percent
  binary_sensors:
    - type: generic_boolean
      id: switch_1
      advertise_immediately: true
    - type: generic_boolean
      id: switch_2
      advertise_immediately: true


# Deep sleep - wake on either switch via combined wakeup pin
deep_sleep:
  run_duration: 15s
  sleep_duration: 5min
  wakeup_pin:
    number: 4
    mode: INPUT_PULLUP
    inverted: true

How It Works

Section titled “How It Works”
  1. Normal operation: Device sleeps, both switches readable on D2/D3
  2. Either switch pressed: D4 goes LOW via diode OR circuit
  3. Device wakes: Reads individual switch states from D2 and D3
  4. Broadcasts: Sends both switch states via BTHome
  5. Returns to sleep: After run_duration expires

Power Consumption

Section titled “Power Consumption”
StateCurrent
Deep sleep~3µA
Active~5mA

Expected battery life: 6-12 months with 400mAh battery