ESPHome custom components

A collection of ESPHome external components for hardware that has no (complete) support in ESPHome itself: Remeha boilers over CAN bus, Itho ventilation boxes over I²C, MiLight/MiBoxer lights over 2.4 GHz radio, LD2410S mmWave presence sensors, DCF77 radio clocks and an I²C sniffer for reverse engineering.

Every component ships with a complete, working example configuration.

Component	What it does	Bus / hardware	ESPHome platforms	Example
remeha	Read and write Remeha boiler data and parameters	CAN bus (service connector), ESP32	sensor, text_sensor, number, select, climate	example_remeha.yaml
itho	Control and monitor an Itho ventilation box	I²C, ESP32	fan, select, sensor	example_itho.yaml
mi	MiLight/MiBoxer bulb control and remote emulation	nRF24L01+ over SPI, ESP8266/ESP32	light, button	example_milight.yaml
ld2410s	HLK-LD2410S presence sensor incl. calibration	UART	binary_sensor, sensor, text_sensor, number, select, switch, button	example_ld2410s.yaml
dcf77	Time source from the DCF77 atomic clock signal	GPIO receiver module	time	example_dcf77.yaml
i2c_sniffer	Dumps all captured I²C traffic to the ESPHome log	2 GPIO pins, ESP32	–	example_i2csniffer.yaml

Installation

Add the component(s) you need as an external component:

external_components:
- source: github://hencou/esphome_components
  components: [remeha]   # or itho, mi, ld2410s, dcf77, i2c_sniffer
  refresh: 0s

Pin a specific version by appending a tag or a full commit SHA (github://hencou/esphome_components@1.1.6); short SHAs are rejected by GitHub. After changing the reference, run Clean Build Files once so ESPHome discards the old checkout.

remeha - Remeha boilers over CAN bus

Reads the service bus of a Remeha boiler (developed on a Tzerra Ace Matic) and exposes temperatures, status, modulation, error history and the writable installer parameters as ESPHome entities. The service bus is an RJ12 connector:

Pin	RJ12
1	CAN H
2	CAN L
3	NC
4	GND
5	NC
6	24V

An Olimex ESP32-EVB is convenient because it has a CAN transceiver on board; with a 24 V to 5 V buck converter on pin 6 the board can be powered from the service bus itself. (Use at your own risk.)

canbus:
- platform: esp32_can
  id: can1
  tx_pin: GPIO5
  rx_pin: GPIO35
  can_id: 0
  bit_rate: 1000KBPS

remeha:
  canbus_id: can1
  user_level: 2          # 0 = no authentication, 1 = GUEST, 2 = SERVICE, 3
  auth_key: !secret remeha_auth_key
  boot_delay: 10s        # optional, delay before the boiler is addressed
  min_write_level: 2     # optional, refuse writes below this verified level

Broadcast (PDO) data such as temperatures, status and modulation is available without authentication. The protected service objects and all parameter writes need an authentication handshake, which uses a fixed 32-bit key word that is not included in this repository — supply it via auth_key (with or without 0x, always read as hexadecimal), which is required for user_level 1 and up:

# secrets.yaml
remeha_auth_key: 0x........

With user_level: 0 the handshake is skipped and auth_key may be omitted; only broadcast data is then available. Authentication only succeeds when the boiler reports the requested level as the effective access level, and writes are refused while that verified level is below min_write_level.

How the component talks to the boiler:

• On boot it sends NMT reset/start and reads object 0x4004 on the standard SDO channel (0x601/0x581). The boiler answers with a channel number, from which the request/response ids follow (1 → 0x241/0x1C1, 2 → 0x341/0x2C1), so several clients (Recom, eThermostat, this component) can be on the bus at the same time. A channel change triggers re-authentication.
• Poll entries come from the entities you configure: every sensor, number, select and climate entity registers its own object. A full round is read back to back (next request after the previous response) once a minute, with single keep-alive reads in between so the authorisation does not expire.
• If the CAN controller goes bus-off, the component requests TWAI recovery, restarts the driver and re-runs the boot sequence — ESPHome's esp32_can does not recover by itself.

Entities: sensor (flow/return/outside/DHW temperatures, water pressure, modulation, pump speed, status and error codes, appliance type, …), text_sensor (status/substatus text, write status), number (room, DHW comfort/reduced, night, holiday and anti-legionella setpoints, heating curve slope, room sensor calibration, summer/winter threshold), select (zone mode, time program, CH/DHW enable, anti-legionella, fireplace mode) and climate.

itho - Itho Daalderop ventilation over I²C

An ESPHome port of arjenhiemstra/ithowifi: speaks I²C to the Itho box, exposing it as a fan plus a select for the ventilation mode and sensors for error code, startup counter, operation time, fan setpoint/speed and the optional on-board SHT30 temperature and humidity.

itho:
  syssht30: disable      # or the SHT30 variant on the Itho board
  # syssht30_address: 0x44
  # sda: SDA
  # scl: SCL

fan:
- platform: itho
  name: Fan

select:
- platform: itho
  name: Stand

sensor:
- platform: itho
  update_interval: 8s
  error:
    name: Error
  fan_speed:
    name: Fan speed

example_itho.yaml also contains a standalone PID controller that drives the box from the humidity sensor, including shower detection.

mi - MiLight / MiBoxer lights over 2.4 GHz

An ESPHome implementation of Sidoh's MiLight Hub. Usable as a standalone hub replacement or behind a wall switch, in which case the switch keeps working without WiFi. State updates go out over the native ESPHome API.

mi:
  ce_pin: D2
  csn_pin: D8
  packet_repeats: 50          # optional
  listen_repeats: 20          # optional, packets needed to accept a remote command
  state_flush_interval: 5000  # optional, ms between state reports

light:
- platform: mi
  name: Living room
  mi_device_id: 0xAB01
  group_id: 1
  remote_type: rgb_cct        # rgb_cct, rgb, cct, rgbw, fut089, fut091, fut020, s2
  default_transition_length: 0s

There is also a button platform for pair/unpair. Button press behaviour in example_milight.yaml: short press toggles, long press fades to maximum, two short presses select night mode, three short presses white mode.

ld2410s - HLK-LD2410S mmWave presence sensor

Full support for the LD2410S over UART: presence, target distance, firmware version, per-gate thresholds, detection range and delays, output mode and the auto-calibration routine (button, plus a calibration_progress sensor and has_calibration_running binary sensor).

uart:
  id: uart_bus
  tx_pin: GPIO1
  rx_pin: GPIO3
  baud_rate: 115200

ld2410s:
  uart_id: uart_bus

Note: switch off minimal output mode before starting calibration, otherwise there is no progress reporting. Based on the work of @NovakIrs.

dcf77 - Atomic clock time source

Decodes the time broadcast by the DCF77 transmitter and provides it as an ESPHome time source, so a device can keep accurate time without network access.

time:
- platform: dcf77
  pin: GPIO4
  update_interval: 30min

i2c_sniffer - I²C bus sniffer

Passively captures I²C traffic (based on ozarchie/I2C-sniffer) and dumps every packet to the ESPHome log — handy for reverse engineering devices such as the Itho box.

i2c_sniffer: