Stepper Component

The stepper component allows you to use stepper motors with ESPHome. Currently only the A4988 stepper driver (datasheet) and ULN2003 (datasheet) are supported.

Note

This component will not show up in the Home Assistant front-end automatically because Home Assistant doesn’t have support for steppers. Please see Home Assistant Configuration.

Base Stepper Configuration

All stepper configuration schemas inherit these options.

Configuration variables:

  • max_speed (Required, float): The maximum speed in steps/s (steps per seconds) to drive the stepper at. Note most steppers can’t step properly with speeds higher than 250 steps/s.

  • acceleration (Optional, float): The acceleration in steps/s^2 (steps per seconds squared) to use when starting to move. The default is inf which means infinite acceleration, so the stepper will try to drive with the full speed immediately. This value is helpful if that first motion of the motor is too jerky for what it’s moving. If you make this a small number, it will take the motor a moment to get up to speed.

  • deceleration (Optional, float): The same as acceleration, but for when the motor is decelerating shortly before reaching the set position. Defaults to inf (immediate deceleration).

A4988 Component

Put this code into the configuration file on ESPHome for this device.

stepper:
  - platform: a4988
    id: my_stepper
    step_pin: D0
    dir_pin: D1
    max_speed: 250 steps/s

    # Optional:
    sleep_pin: D2
    acceleration: inf
    deceleration: inf

Configuration variables:

  • id (Required, ID): Specify the ID of the stepper so that you can control it.

  • step_pin (Required, Pin Schema): The STEP pin of the A4988 stepper driver.

  • dir_pin (Required, Pin Schema): The DIRECTION pin of the A4988 stepper driver.

  • sleep_pin (Optional, Pin Schema): Optionally also use the SLEEP pin of the A4988 stepper driver. If specified, the driver will be put into sleep mode as soon as the stepper reaches the target steps.

  • All other from Base Stepper Configuration.

Note

If the stepper is driving in the wrong direction, you can invert the dir_pin:

stepper:
  - platform: a4988
    # ...
    dir_pin:
      number: D1
      inverted: True

ULN2003 Component

Put this code into the configuration file on ESPHome for this device.

# Example configuration entry
stepper:
  - platform: uln2003
    id: my_stepper
    pin_a: D0
    pin_b: D1
    pin_c: D2
    pin_d: D3
    max_speed: 250 steps/s

    # Optional:
    acceleration: inf
    deceleration: inf

Configuration variables:

  • id (Required, ID): Specify the ID of the stepper so that you can control it.

  • pin_a (Required, Pin Schema): The pin a of the stepper control board.

  • pin_b (Required, Pin Schema): The pin b of the stepper control board.

  • pin_c (Required, Pin Schema): The pin c of the stepper control board.

  • pin_d (Required, Pin Schema): The pin d of the stepper control board.

  • sleep_when_done (Optional, boolean): Whether to turn off all coils when the stepper has reached the target position

  • step_mode (Optional, string): The step mode to operate the motor with. One of:

    • FULL_STEP (Default)

    • HALF_STEP

    • WAVE_DRIVE

  • All other from Base Stepper Configuration.

stepper.set_target Action

To use your stepper motor in automations or templates, you can use this action to set the target position (in steps). The stepper will always run towards the target position and stop once it has reached the target.

on_...:
  then:
  - stepper.set_target:
      id: my_stepper
      target: 250

  # Templated
  - stepper.set_target:
      id: my_stepper
      target: !lambda |-
        if (id(my_binary_sensor).state) {
          return 1000;
        } else {
          return -1000;
        }

Configuration options:

  • id (Required, ID): The ID of the stepper.

  • target (Required, int, templatable): The target position in steps.

Warning

This turns the stepper to an absolute position! To have the servo move relative to the current position, first reset the current position and then set the target to the relative value.

on_...:
  then:
    # Move 150 steps forward
    - stepper.report_position:
        id: my_stepper
        position: 0
    - stepper.set_target:
        id: my_stepper
        target: 150

stepper.report_position Action

All steppers start out with a target and current position of 0 on boot. However, if you for example want to home a stepper motor, it can be useful to report the stepper where it is currently at.

With this action, you can set the stepper’s internal position counter to a specific value (in steps). Please note that reporting the position can create unexpected moves of the stepper. For example, if the stepper’s target and current position is at 1000 steps and you “report” a position of 0, the stepper will move 1000 steps forward to match the target again.

on_...:
  then:
  - stepper.report_position:
      id: my_stepper
      position: 250
  # It's best to call set_target directly after report_position, so that the stepper doesn't move
  - stepper.set_target:
      id: my_stepper
      target: 250

  # Templated
  - stepper.report_position:
      id: my_stepper
      position: !lambda |-
        if (id(my_binary_sensor).state) {
          return 0;
        } else {
          return -1000;
        }

Configuration variables:

  • id (Required, ID): The ID of the stepper.

  • position (Required, int, templatable): The position to report in steps.

stepper.set_speed Action

This Action allows you to set the speed of a stepper at runtime.

on_...:
  - stepper.set_speed:
      id: my_stepper
      speed: 250 steps/s

Configuration variables:

  • id (Required, ID): The ID of the stepper.

  • speed (Required, templatable, float): The speed in steps/s (steps per seconds) to drive the stepper at.

Home Assistant Configuration

This component will not show up in the Home Assistant front-end (Overview) automatically because Home Assistant does not support steppers natively.

You can add the stepper component code below to your Home Assistant configuration (configuration.yaml) to be able to control the stepper from the front-end.

# Add a slider control to Home Assistant to set an integer value
input_number:
  stepper_control:
    name: Stepper Control
    initial: 0
    min: -1000
    max: 1000
    step: 1
    mode: slider

# Do something when the slider changes
automation:
  - alias: Write Stepper Value to ESP
    trigger:
      platform: state
      entity_id: input_number.stepper_control
    action:
      # Replace livingroom with the name you gave the ESP
      - service: esphome.livingroom_control_stepper
        data_template:
          target: '{{ trigger.to_state.state | int }}'

In the above code, “stepper_control” is the ID of a numeric input field. It must be unique and it is used in the automation section as a reference name. The display name for this field is in stepper_control’s name key.

If you want your user interface to give you more control over your stepper controller, such as setting the acceleration, deceleration, etc, then you can add more input fields after stepper_control but before automation. They can be a simple number-entry field (mode: box) or a slider like this. Each of these extra input fields needs an associated input parameter defined on the ESPHome device’s API service.

The automation section tells Home Assistant what to do when the slider changes. It needs a trigger (state of the stepper_control slider) and an action. In the trigger section, entity_id must refer back to the configuration ID that triggers the automation. For us, that is the stepper_control field in the input_number item. That’s why the value is input_number.stepper_control.

In the action section, the service name is vital to get right: it’s the glue that connects Home Automation’s front-end to the ESPHome device configuration. While you might expect the syntax to be esphome.<your_device>.<api_service>, the correct syntax is to join the device ID to the API service ID with an underscore, as in esphome.livingroom_control_stepper where “Livingroom” is a device in ESPHome and “control_stepper” is an API service for that device.

The template string is used to get the “state” value from the target field (defined in the target section) on the input_number component of the Home Assistant front-end. This value is then passed to the API service as defined in the ESPHome device’s configuration. The data_template section lists one value for each of the input parameters on the service being called by the automation. In our case, the ESPHome device has an API service with a single parameter, “target”. If you called this “my_target”, then the last line above should be my_target: '{{ trigger.to_state.state | int }}'. Getting this linkage right is very important.

The following code needs to go in the ESPHome configuration file for this device. Above, we mention “API service” a lot. This code is where that is defined. You may have already added it (or something similar). Note that the input variable for the control_stepper service is called target. That’s what matches with the automation configuration above. Also note that the variable target is defined as an integer. That means it must be an integer number, not a string.

# ESPHome configuration
api:
  services:
    - service: control_stepper
      variables:
        target: int
      then:
        - stepper.set_target:
            id: my_stepper
            target: !lambda 'return target;'

stepper:
  - platform: ...
    # [...] stepper config
    id: my_stepper

lambda calls

From lambdas, you can call several methods on stepper motors to do some advanced stuff (see the full API Reference for more info).

  • set_target: Set the target position of the motor as an integer.

    // Argument is integer (signed int)
    // Set the (absolute) target position to 250 steps
    id(my_stepper).set_target(250);
    
  • report_position: Report the current position as an integer.

    // Report the (absolute) current position as 250 steps
    id(my_stepper).report_position(250);
    
  • current_position: Get the current position of the stepper as an integer.

    int pos = id(my_stepper).current_position;
    
  • target_position: Get the set target position of the stepper as an integer.

    int pos = id(my_stepper).target_position;
    

See Also