ESPHome component that proxies a Switcher water heater from an isolated IoT network to Home Assistant.

Why?

Switcher devices communicate via UDP broadcasts, which don't cross network boundaries. If your Switcher is on a separate IoT VLAN, you typically need a UDP relay on your router.

This component runs on an ESP32 in the IoT network and:

Listens for Switcher UDP broadcasts (auto-discovery)
Exposes the device to Home Assistant via ESPHome's native API
Sends TCP commands to control on/off

No UDP relay needed. Home Assistant initiates the connection to the ESP32.

Installation

Add to your ESPHome config:

external_components:
  - source:
      type: git
      url: https://github.com/backslasher/switcher-proxy
      ref: main
    components: [switcher_proxy]
switcher_proxy:
  devices:
    - name: "Water Heater"
      # switcher_id: "aabbcc"  # omit to auto-discover first device
      power_sensor:
        name: "Water Heater Power"
      remaining_time_sensor:
        name: "Water Heater Time Remaining"

If switcher_id is omitted, the component locks onto the first Switcher it sees broadcasting. With multiple Switchers, specify the ID to avoid ambiguity.

Finding your Switcher ID

Run this on any Linux machine on the same network as your Switcher:

sudo tcpdump -i any udp port 20002 -c 10 -w - 2>/dev/null | python3 -c '
import sys
seen, data, pos = set(), sys.stdin.buffer.read(), 24
while pos + 16 <= len(data):
    pkt_len = int.from_bytes(data[pos+8:pos+12], "little")
    pkt, pos = data[pos+16:pos+16+pkt_len], pos + 16 + pkt_len
    if len(pkt) < 117: continue
    payload = pkt[42:]
    device_id, name = payload[18:21].hex(), payload[42:74].rstrip(b"\x00").decode("utf-8", errors="ignore")
    if device_id not in seen: seen.add(device_id); print(f"switcher_id: \"{device_id}\"  # {name}")
'

Example output:

switcher_id: "ab12cd"  # Boiler
switcher_id: "ef34ab"  # Water Heater

Configuration

switcher_proxy:
  devices:
    - name: "Water Heater"
      switcher_id: "aabbcc"
      power_sensor:
        name: "Water Heater Power"
      remaining_time_sensor:
        name: "Water Heater Time Remaining"
    - name: "Boiler"
      switcher_id: "ddeeff"
      power_sensor:
        name: "Boiler Power"

Options

Option	Required	Description
`name`	Yes	Name of the switch entity
`switcher_id`	No	Filter for specific Switcher (hex, e.g., `aabbcc`). If omitted, locks onto first device seen.
`power_sensor`	No	Sensor for power consumption (watts)
`remaining_time_sensor`	No	Sensor for remaining run time (seconds)

Supported Devices

Currently supports Type 1 Switcher devices:

Switcher V2
Switcher Touch
Switcher V4
Switcher Mini
Switcher Power Plug

Development

Run protocol unit tests:

uv venv && uv pip install platformio
uv run pio test -e native

Regenerate test vectors from aioswitcher:

python3 scripts/generate_test_vectors.py > test/test_vectors.h

License

MIT

Credits

Protocol implementation based on aioswitcher.