2026.10.4
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1-Wire

The 1-Wire integrationIntegrations connect and integrate Home Assistant with your devices, services, and more. [Learn more] brings devices on a 1-Wire bus into Home Assistant. 1-Wire is a low-cost bus that is popular for DIY projects. A single pair of wires can connect many temperature sensors, counters, and input/output chips.

The integration connects to an owserver instance, which talks to your 1-Wire adapter. For example, you can:

  • Monitor the temperature of rooms, freezers, aquariums, or heating pipes with DS18B20 sensors.
  • Count pulses from water, gas, or electricity meters with a DS2423 counter.
  • Switch relays and read contacts with DS2408 or DS2413 input/output chips.
  • Measure humidity, pressure, or light with multisensors.

Every 1-Wire device has a globally unique ID. The first two characters are the device family, which tells the integration what kind of device it is. For example, 28.FF5C68521604 is a DS18B20 temperature sensor (family 28).

Supported devices

The following device families are supported:

  • 05: DS2405 addressable switch
  • 10: DS18S20 temperature sensor
  • 12: DS2406 dual addressable switch, also used in the TAI-8570 pressure sensor
  • 1D: DS2423 dual counter
  • 1F: DS2409 coupler for bus branching, which creates a device without entities
  • 20: DS2450 quad analog-to-digital converter
  • 22: DS1822 temperature sensor
  • 26 and A6: DS2438 smart battery monitor, often used as a multisensor
  • 28: DS18B20 temperature sensor
  • 29: DS2408 8-channel addressable switch
  • 30: DS2760 battery monitor, often used with a type K thermocouple
  • 3A: DS2413 dual-channel addressable switch
  • 3B: DS1825 temperature sensor
  • 42: DS28EA00 temperature sensor
  • 7E: Embedded Data Systems multisensors: EDS0065 (temperature and humidity), EDS0066 (temperature and pressure), and EDS0068 (temperature, humidity, pressure, and light)
  • EF: Hobby Boards temperature and humidity sensor, moisture meter, and hub

Devices with family 01 (ID chips) and 81 (adapter ID chips) are recognized, but they do not provide any entities.

Multisensors based on DS2438 and DS2760

The DS2438 and DS2760 are often used as general-purpose measurement chips. By adding standard components, they can measure humidity, pressure, light, or thermocouple temperatures. owserver provides ready-made conversions for these setups, and the integration reads them:

  • Humidity: with a compatible Honeywell (HIH3600, HIH4000, HIH5030) or Humirel (HTM1735) sensor on a DS2438
  • Pressure: with a B1-R1-A barometer on a DS2438
  • Illuminance: with an S3-R1-A light sensor on a DS2438
  • Thermocouple temperature: with a type K thermocouple on a DS2760

The raw measurements of these chips are also available as separate entities. For more details, refer to the owfs documentation for the DS2438 and the DS2760.

The TAI-8570 from AAG Electronica combines a DS2406 with a barometer and a temperature sensor. The integration can read its pressure and temperature.

Hobby Boards sold DIY 1-Wire boards. The company is no longer active, but the integration still supports its temperature and humidity sensor, moisture meter, and hub.

Unsupported devices

The following devices are not supported:

  • Device families and types that are not listed under Supported devices. The integration ignores them and writes a warning to the log.
  • 1-Wire devices that are not available through owserver, such as sensors connected directly to the GPIO pins of a Raspberry Pi without owserver.

Prerequisites

  • A 1-Wire adapter, such as a USB, serial, or I2C adapter, with your devices connected to it.
  • An owserver instance that can access the adapter. owserver is part of the owfs 1-Wire file system. You can run it on the same machine as Home Assistant or on another machine on your network. If you use Home Assistant Operating SystemHome Assistant OS, the Home Assistant Operating System, is an embedded, minimalistic, operating system designed to run the Home Assistant ecosystem on single board computers (like the Raspberry Pi) or Virtual Machines. It includes Home Assistant Core, the Home Assistant Supervisor, and supports apps. Home Assistant Supervisor keeps it up to date, removing the need for you to manage an operating system. Home Assistant Operating System is the recommended installation type for most users., you can install owserver as a community appApps are additional standalone third-party software packages that can be installed on Home Assistant OS. [Learn more].
  • The hostname or IP address and the port of owserver. The default port is 4304.

Configuration

To add the 1-Wire hub to your Home Assistant instance, use this My button:

1-Wire can be auto-discovered by Home Assistant. If an instance was found, it will be shown as Discovered. You can then set it up right away.

Manual configuration steps

If it wasn’t discovered automatically, don’t worry! You can set up a manual integration entry:

Home Assistant can discover owserver automatically, either when it announces itself on your network or when it runs as an appApps are additional standalone third-party software packages that can be installed on Home Assistant OS. [Learn more]. In that case, confirm the setup when Home Assistant asks for it.

Host

The hostname or IP address of your owserver instance. The default is localhost.

Port

The port of your owserver instance. The default is 4304.

Configuration options

You can change the precision that the integration uses to read DS18B20 temperature sensors (family 28). Lower precision makes the sensor respond faster, but less accurately. The selected precision is visible in the device_file attribute of the Temperature entity, for example /28.FF5C68521604/temperature11.

This option only changes how Home Assistant reads the sensor. To change the resolution stored in the sensor itself, use the Temperature resolution select entity instead.

To change the options, go to Settings > Devices & services, select 1-Wire, and then select the cogwheel on the entry. Home Assistant reloads the integration after you save the options.

Reset all device customizations

Resets the options of all devices to their default values.

Customize specific devices

Select the DS18B20 sensors you want to configure. Home Assistant then asks for the Sensor precision of each selected sensor. If no DS18B20 sensors are connected, Home Assistant shows that no configurable devices were found.

Sensor precision

The precision of the temperature reading: Default, 9 Bits, 10 Bits, 11 Bits, or 12 Bits. The default is Default, which uses the precision stored in the sensor.

Supported functionality

The integration creates one device for each 1-Wire device it finds on the bus. Devices connected to a DS2409 coupler are linked to that coupler. Each entity has a device_file attribute with the path of the value in owserver, for example /28.FF5C68521604/temperature.

Many entities are disabled by default, so that the integration does not read unnecessary data from the bus. You can turn them on from the device page.

Binary sensors

All binary sensors are disabled by default.

  • Sensed, Sensed A/B, and Sensed 0–7
    • Description: The state of an input channel
    • Available for: DS2405 (05), DS2406 (12), DS2408 (29), and DS2413 (3A)
  • Hub short on branch 0–3
    • Description: Whether a short circuit is detected on a hub branch
    • Available for: Hobby Boards hub (EF)

Selects

  • Temperature resolution
    • Description: The resolution stored in the temperature sensor
    • Options: 9 bits (0.5°C, fastest, up to 93.75ms), 10 bits (0.25°C, up to 187.5ms), 11 bits (0.125°C, up to 375ms), 12 bits (0.0625°C, slowest, up to 750ms)
    • Available for: DS18B20 (28)
    • Remarks: This entity is disabled by default

Sensors

  • Temperature
    • Description: The measured temperature
    • Available for: Temperature sensors (10, 22, 28, 3B, 42), DS2406 with TAI-8570 (12), DS2438 (26, A6), DS2760 (30), Embedded Data Systems (7E), and Hobby Boards temperature and humidity sensor (EF)
    • Remarks: Disabled by default for the TAI-8570
  • Humidity
    • Description: The measured relative humidity
    • Available for: DS2438 (26, A6), Embedded Data Systems EDS0065 and EDS0068 (7E), and Hobby Boards temperature and humidity sensor (EF)
    • Remarks: Disabled by default for the DS2438
  • HIH3600 humidity, HIH4000 humidity, HIH5030 humidity, and HTM1735 humidity
    • Description: The relative humidity, converted for the humidity sensor connected to the DS2438
    • Available for: DS2438 (26, A6)
    • Remarks: These entities are disabled by default
  • Raw humidity
    • Description: The relative humidity before correction
    • Available for: Hobby Boards temperature and humidity sensor (EF)
  • Pressure
    • Description: The measured air pressure, in mbar
    • Available for: DS2406 with TAI-8570 (12), DS2438 with B1-R1-A (26, A6), and Embedded Data Systems EDS0066 and EDS0068 (7E)
    • Remarks: Disabled by default for the DS2406 and the DS2438
  • Illuminance
    • Description: The measured light level, in lx
    • Available for: DS2438 with S3-R1-A (26, A6) and Embedded Data Systems EDS0068 (7E)
    • Remarks: Disabled by default for the DS2438
  • Counter A/B
    • Description: The pulse count of each counter input
    • Available for: DS2423 (1D)
  • Voltage A–D and Latest voltage A–D
    • Description: The voltage of each input
    • Available for: DS2450 (20)
    • Remarks: Voltage starts a new conversion, while Latest voltage reads the last converted value. The Latest voltage entities are disabled by default
  • VAD voltage, VDD voltage, and VIS voltage difference
    • Description: The raw voltages measured by the DS2438
    • Available for: DS2438 (26, A6)
    • Remarks: These entities are disabled by default
  • Voltage, VIS voltage gradient, and Thermocouple K temperature
    • Description: The raw voltages measured by the DS2760, and the temperature of a connected type K thermocouple
    • Available for: DS2760 (30)
    • Remarks: These entities are disabled by default
  • Moisture 0–3 or Wetness 0–3
    • Description: The soil moisture, in cbar, or the leaf wetness, in %, of each channel, depending on the sensor type configured for the channel
    • Available for: Hobby Boards moisture meter (EF)
    • Remarks: After you change the sensor type of a channel with the Leaf sensor or Moisture sensor switch, reload the integration to get the matching entity

Switches

All switches are disabled by default.

  • Programmed input-output, Programmed input-output A/B, and Programmed input-output 0–7
    • Description: Turns an output channel on or off
    • Available for: DS2405 (05), DS2406 (12), DS2408 (29), and DS2413 (3A)
  • Latch A/B and Latch 0–7
    • Description: The activity latch of an input channel, which records whether the input changed
    • Available for: DS2406 (12) and DS2408 (29)
  • Current A/D control
    • Description: Turns the current measurement of the DS2438 on or off
    • Available for: DS2438 (26, A6)
  • Hub branch 0–3
    • Description: Turns a hub branch on or off
    • Available for: Hobby Boards hub (EF)
  • Leaf sensor 0–3 and Moisture sensor 0–3
    • Description: Sets the sensor type of each channel to leaf wetness or soil moisture
    • Available for: Hobby Boards moisture meter (EF)

1-Wire automation examples

1-Wire sensors and switches are often used to monitor and control things around the house. Here are some ideas to get you started.

Tip

You don’t need to edit YAML to use these examples. Copy a YAML snippet from this page, open the visual automation editor in Home Assistant, and press Ctrl+V (or Cmd+V on Mac). Home Assistant automatically converts the pasted YAML into the visual editor format, whether it’s a full automation, a single trigger, a condition, or an action.

Automation: Get notified when the freezer gets too warm

Use a DS18B20 temperature sensor in your freezer to send a notification to your phone when the temperature rises above -10°C for 10 minutes. Replace the entity IDs in the example with the entity IDs of your sensor and phone.

  • Trigger: Numeric state crossed threshold
    • Entity: Your freezer’s Temperature sensor
    • Above: -10
    • For at least: 10 minutes
  • Action: Send a notification message
    • Target: My Device (notify.my_device)
YAML example for notifying when the freezer gets too warm
AutomationAutomations in Home Assistant allow you to automatically respond to things that happen in and around your home. [Learn more] 
alias: "Notify when the freezer gets too warm"
triggers:
  - trigger: numeric_state
    entity_id: sensor.28_ff5c68521604_temperature
    above: -10
    for:
      minutes: 10
actions:
  - action: notify.send_message
    target:
      entity_id: notify.my_device
    data:
      message: "The freezer temperature is above -10°C."

Automation: Turn on a heater relay when the greenhouse gets cold

Use a temperature sensor and a relay connected to an output of a DS2413 to protect plants from frost. This example turns on the relay when the temperature drops below 5°C. The Programmed input-output switches are disabled by default, so enable the one you use first. Replace the entity IDs in the example with the entity IDs of your sensor and switch.

  • Trigger: Numeric state crossed threshold
    • Entity: Your greenhouse Temperature sensor
    • Below: 5
  • Action: Turn on switch
    • Target: Your relay’s Programmed input-output A switch
YAML example for turning on a heater relay when the greenhouse gets cold
AutomationAutomations in Home Assistant allow you to automatically respond to things that happen in and around your home. [Learn more] 
alias: "Turn on the greenhouse heater when it gets cold"
triggers:
  - trigger: numeric_state
    entity_id: sensor.28_a05966040000_temperature
    below: 5
actions:
  - action: switch.turn_on
    target:
      entity_id: switch.3a_0b2c4e000000_programmed_input_output_a

Data updates

The 1-Wire integration pollsData polling is the process of querying a device or service at regular intervals to check for updates or retrieve data. By defining a custom polling interval, you can control how frequently your system checks for new data, which can help optimize performance and reduce unnecessary network traffic. [Learn more] each entity every 30 seconds.

The integration also scans the bus for new devices every 5 minutes. New devices and their entities are added automatically, so you do not need to reload the integration after you connect a new sensor. On DS2409 couplers, the integration searches both the main and the aux branches.

Known limitations

  • The integration only connects to owserver. It cannot read 1-Wire devices directly from an adapter or from the GPIO pins of a Raspberry Pi.
  • Bus branching is only supported with DS2409 couplers.
  • Only DS18B20 temperature sensors have configuration options.
  • Devices that you disconnect from the bus are not removed automatically, because a device that is temporarily unreachable looks the same as a removed one. To remove a device you no longer use, see Removing a device you no longer use.
  • When you connect a new device, it can take up to 5 minutes before it appears in Home Assistant.
  • On the Hobby Boards moisture meter, a change of sensor type only takes effect after you reload the integration.

Troubleshooting

Home Assistant cannot connect to owserver

Symptom: Setup fails with a connection error

When you set up the integration, you get an error that Home Assistant failed to connect.

Description

Home Assistant cannot reach owserver at the host and port you entered.

Resolution

If owserver is not reachable when Home Assistant starts, the integration retries automatically.

  1. Check that owserver is running and that it can access your 1-Wire adapter.
  2. Check the host and port. The default port is 4304.
  3. If owserver runs on another machine, check that it accepts connections from your network and not only from localhost.
  4. If owserver moved to another address, go to Settings > Devices & services, select 1-Wire, then the three dots menu next to the entry, and select Reconfigure. Enter the new host and port.
A device on the bus does not appear

Symptom: A connected device is missing in Home Assistant

A device is connected to the bus, but Home Assistant does not show it.

Description

The integration only adds devices from the supported device families, and it scans for new devices every 5 minutes. The device might also not be visible to owserver.

Resolution

  1. Wait 5 minutes for the next scan.
  2. Go to Settings > System > Logs and look for a message that the integration ignores an unknown device family or type.
  3. Check that the device appears in owserver, for example with the owdir command or in the owhttpd web interface.
  4. Check the wiring of the device.
Some entities are missing

Symptom: A device has fewer entities than listed on this page

A device appears in Home Assistant, but some of its entities are missing.

Description

Many entities are disabled by default, including all binary sensors and switches. Some entities only exist when the matching hardware is connected, such as the TAI-8570 sensors.

Resolution

  1. Go to Settings > Devices & services and select 1-Wire.
  2. Select the device.
  3. Select +N disabled entities, where N is the number of disabled entities.
  4. Select the entity, then select the cogwheel .
  5. Turn on Enabled, and select Update.
An entity shows unknown

Symptom: An entity shows an unknown state

An entity shows Unknown, and Settings > System > Logs contains a message about an error fetching data.

Description

Home Assistant could not read the value from owserver. This usually happens when the device lost its connection to the bus.

Resolution

  1. Check the wiring and the power of the device.
  2. Check that the device still appears in owserver.

The entity recovers automatically on the next successful reading.

A DS18B20 reports 85°C

Symptom: A DS18B20 temperature sensor reports 85°C

A DS18B20 temperature sensor suddenly reports 85°C, even though the real temperature is different.

Description

85°C is the power-on value of the DS18B20. The sensor reports it when it loses power during a measurement, for example because of a wiring problem or when it uses parasitic power. There is no way to distinguish a real 85°C reading from an incorrect one.

Resolution

  1. Check the wiring of the sensor.

  2. If possible, power the sensor with a separate supply wire instead of parasitic power.

  3. If the problem remains, you can create a template sensor helperA helper is a virtual entity you create inside Home Assistant. It is not backed by a physical device. Helpers store values, track state, or do calculations that your automations and dashboards need. [Learn more] that filters out the value. Go to Settings > Devices & services > Helpers, create a template sensor, and use a state template such as:

    {% if states('sensor.28_a05966040000_temperature') | float(0) != 85 %}
  {{ states('sensor.28_a05966040000_temperature') }}
{% else %}
  None
{% endif %}

Removing the integration

This integration follows standard integration removal. No extra steps are required.

To remove an integration instance from Home Assistant

  1. Go to Settings > Devices & services and select the integration card.
  2. Next to the entry you want to remove, select the three dots menu. Then, select Delete.
    • Depending on the integration, the entries are listed under one of the following headings:
      • Devices
      • Hubs
      • Services
      • Integration entries
  3. To confirm, select Delete.
    • Home Assistant also deletes the devices and entities of the entry.
  4. If Home Assistant asks you to restart, restart Home Assistant.
  5. If Home Assistant asks whether to also delete the application credentials, select Remove or Keep.

Removing a device you no longer use

The integration does not remove devices that you disconnect from the bus. To remove one:

  1. Disconnect the device from the bus.
  2. Go to Settings > Devices & services and select 1-Wire.
  3. Select the three dots menu next to the entry, and select Reload.
  4. Select the device, then select the three dots menu and select Delete.

You can only delete a device that the integration no longer finds on the bus.