Bosch WTWH7540/12 Dryer - has a EPT58131

[MichaelHeimann]

Model (E-Nr.)

WTWH7540/12

Spare parts page

https://www.bosch-home.lu/de/supportdetail/product/WTWH7540/12#/Tabs=section-spareparts/

Appliance type

Dryer

Your contribution

I've now finally used a BSH Board from @Bouni to make my dryer smart (again?) after its homeconnect module failed.

Here's some pictures for reference:

front of the machine:

backside of the frontpanel with only the top lid off - the 3pin brown connector is connected to the homeconnect module:

Here's the frontpanel half way removed (three screws next to the watertank) and also the homeconnect module disconnected.

closer look on the homeconnect pcb and the sticker of the frontpanel PCB

I used the top port here, since the homeconnect port on the frontpanel PCB is only powered/active when remote start("Fernstart" in german) is activated - which I don't trust I will be able to ;)

which is one of the many 3pin d-bus ports this EPT58131 provides (as already documented).

This is the esphome config I used for the BSH board (shamelessly inspired by the existing WT47W5W0 config and modified for the BSH Board ;) ):

esphome:
  name: "bsh-board-trockner"
  friendly_name: BSH Board Trockner
  min_version: 2025.11.0
  name_add_mac_suffix: false

external_components:
  - source: github://hn/bsh-home-appliances@master


esp32:
  variant: esp32c6
  framework:
    type: esp-idf

# Enable logging
logger:

time:
  - platform: homeassistant
    id: ha_time


# Enable Home Assistant API
api:

# Allow Over-The-Air updates
ota:
- platform: esphome

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password


# d-bus config from now on

output:
  - platform: gpio
    pin: 
      number: GPIO07
      inverted: true
    id: activity_led

uart:
  id: dbus_uart
  rx_pin: GPIO4
  tx_pin: GPIO5
  baud_rate: 9600
  debug:
    direction: BOTH
    dummy_receiver: false
    after:
      # Trigger after 1 byte to ensure the LED blinks immediately
      bytes: 1
    sequence:
      - output.turn_on: activity_led
      - delay: 20ms
      - output.turn_off: activity_led

bshdbus:
  uart_id: dbus_uart

status_led:
  pin:
    number: GPIO06
    inverted: true

binary_sensor:
  - platform: bshdbus
    dest: 0x11
    command: 0x1006
    binary_sensors:
      - id: bsh_dryer_low_heat
        name: Schontrocknen
        icon: mdi:feather
        lambda: return (x[6]) & 0x04;
  
sensor:
  - platform: bshdbus
    dest: 0x21
    command: 0x1002
    sensors:
      - id: bsh_dryer_time_remaining
        name: Restzeit
        icon: mdi:clock-outline
        device_class: duration
        state_class: measurement
        unit_of_measurement: min
        accuracy_decimals: 0
        lambda: return (x[0] << 8 | x[1]) / 60;
  - platform: bshdbus
    dest: 0x11
    command: 0x1006
    sensors:
      - id: bsh_dryer_anti_crease_time
        name: Knitterschutz
        icon: mdi:shield-refresh
        device_class: duration
        state_class: measurement
        unit_of_measurement: min
        accuracy_decimals: 0
        lambda: return ((int16_t)x[1]);

text_sensor:
  - platform: bshdbus
    dest: 0x11
    command: 0x1006
    text_sensors:
      - id: bsh_dryer_program
        name: Trocknungsprogramm
        icon: mdi:tshirt-crew-outline
        lambda: return std::to_string(x[0]);
        filters:
          - map:
            - 0 -> Aus
            - 1 -> Baumwolle
            - 2 -> Pflegeleicht
            - 3 -> Mix
            - 4 -> Outdoor
            - 5 -> Wolle finish
            - 6 -> zeitlich kalt
            - 7 -> zeitlich warm
            - 8 -> Hygiene
            - 9 -> Super 40
            - 10 -> Handtücher
            - 11 -> Outdoor
            - 12 -> Kopfkissen
            - 13 -> Steppdecken
            - 14 -> Hemden
            - 15 -> Pflegeleicht extratrocken
            - 16 -> Dessous
  - platform: bshdbus
    dest: 0x11
    command: 0x1006
    text_sensors:
      - id: bsh_dryer_fine_adjust
        name: Trockengrad
        icon: mdi:white-balance-sunny
        lambda: return std::to_string(x[4]);
        filters:
          - map:
            - 6 -> Aus
            - 8 -> I
            - 10 -> II
            - 12 -> III
  - platform: bshdbus
    dest: 0x21
    command: 0x1000
    text_sensors:
      - id: bsh_dryer_door
        name: Tür
        icon: mdi:door
        lambda: return std::to_string(x[1]);
        filters:
          - map:
            - 0 -> unbekannt
            - 3 -> Offen
            - 6 -> Geschlossen
  - platform: bshdbus
    dest: 0x21
    command: 0x1000
    text_sensors:
      - id: bsh_dryer_status
        name: Trockner Status
        icon: mdi:tumble-dryer
        lambda: return std::to_string(x[0]);
        filters:
          - map:
            # a lot more status codes available
            - 12 -> Bereit/Pause
            - 20 -> Aus
            - 22 -> Läuft
  - platform: bshdbus
    dest: 0x11
    command: 0x1001
    text_sensors:
      - id: bsh_dryer_ready
        name: Trockner Startbereit
        icon: mdi:tumble-dryer
        lambda: return std::to_string(x[0]);
        # Values unclear
        filters:
          - map:
            - 1 -> In betrieb
            - 3 -> Startbereit
            - 35 -> Gestartet
            - 36 -> verzögerter Start
  - platform: bshdbus
    dest: 0x21
    command: 0x1004
    text_sensors:
      - id: bsh_dryer_finished
        name: Trockner Fertig
        icon: mdi:tumble-dryer
        lambda: return std::to_string(x[0]);
        filters:
          - map:
            - 12 -> Bereit/Pause
            - 22 -> Läuft
  - platform: bshdbus
    dest: 0x11
    command: 0x1006
    text_sensors:
      - id: bsh_dryer_drying_goal
        name: Trockenziel
        icon: mdi:target
        lambda: return std::to_string(x[2]);
        filters:
          - map:
            - 0 -> Bügeln
            - 2 -> Schrank
            - 3 -> Schrank+

And this is it in HA:

I might update the esphome code when I use the dryer more often but now I'm very happy with what I have already.

Ideas/TBD:

• Kindersicherung
• Fernstart (homeconnect module simulation)

Please confirm

• I understand that I am not allowed to upload copyrighted material, particularly images, exploded views, or firmware binaries that I do not own.
• I read and understood the safety warnings.
• I checked the exploded diagrams on the spare parts page to learn more about my home appliance.
• I searched the discussion forum and the contrib directory for similar problems or appliance types.

[hn]

It's interesting, they placed the COM1 module directly at the (plastic) front, so they avoid the WiFi being shielded by metal parts.

I wonder why the COM1 module "failed". I've done some pretty wild things with COM1 modules and never managed to break them.

[MichaelHeimann]

It didn't connect to wifi anymore and also the wifi setup procedure from the manual just threw an error.

I think it just felt neglected.

I didn't do anything crazy. Besides locking it away in a iot vlan without internet access (only for initial registration), hitting it hard with ipv6 (but I fed it ipv4, too) and then not using the homeconnect app but only the HA integration. That only worked "sometimes" and my expectation-level of a "machine is done" message is "always" - I ignored the smart functionality completely.