esphome-docs/components/sensor/pulse_counter.rst

Pulse Counter Sensor
====================

.. seo::
    :description: Instructions for setting up pulse counter sensors.
    :image: pulse.svg

The pulse counter sensor allows you to count the number of pulses and the frequency of a signal
on any pin.

On the ESP32, this sensor is even highly accurate because it's using the hardware `pulse counter
peripheral <https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/pcnt.html>`__
on the ESP32. However, due to the use of the pulse counter peripheral, a maximum of 8 channels can be used! 

.. figure:: images/pulse-counter.png
    :align: center
    :width: 80.0%

.. code-block:: yaml

    # Example configuration entry
    sensor:
      - platform: pulse_counter
        pin: 12
        name: "Pulse Counter"

Configuration variables:
------------------------

- **pin** (**Required**, :ref:`config-pin`): The pin to count pulses on.
- **name** (**Required**, string): The name of the sensor.
- **count_mode** (*Optional*): Configure how the counter should behave
  on a detected rising edge/falling edge.

  - **rising_edge** (*Optional*): What to do when a rising edge is
    detected. One of ``DISABLE``, ``INCREMENT`` and ``DECREMENT``.
    Defaults to ``INCREMENT``.
  - **falling_edge** (*Optional*): What to do when a falling edge is
    detected. One of ``DISABLE``, ``INCREMENT`` and ``DECREMENT``.
    Defaults to ``DISABLE``.
    

- **use_pcnt** (*Optional*, boolean): Use hardware ``PCNT`` pulse counter. Only supported on ESP32. Defaults to ``true``.

- **internal_filter** (*Optional*, :ref:`config-time`): If a pulse shorter than this
  time is detected, it’s discarded and no pulse is counted. Defaults to ``13us``. On the ESP32, when using the hardware pulse counter
  this value can not be higher than ``13us``, for the ESP8266 or with ``use_pcnt: false`` you can use larger intervals too.
  If you enable this, set up the ``count_mode`` to increase on the falling edge, not leading edge. For S0 pulse meters that are used to meter power consumption 50-100 ms is a reasonable value.

- **update_interval** (*Optional*, :ref:`config-time`): The interval to check the sensor. Defaults to ``60s``.

- **id** (*Optional*, :ref:`config-id`): Manually specify the ID used for code generation.

- **total** (*Optional*): Report the total number of pulses.

- All other options from :ref:`Sensor <config-sensor>`.

.. note::

    See :doc:`integration sensor </components/sensor/integration>` for summing up pulse counter
    values over time.

Converting units
----------------

The sensor defaults to measuring its values using a unit of measurement
of “pulses/min”. You can change this by using :ref:`sensor-filters`.
For example, if you’re using the pulse counter with a photodiode to
count the light pulses on a power meter, you can do the following:

.. code-block:: yaml

    # Example configuration entry
    sensor:
      - platform: pulse_counter
        pin: 12
        unit_of_measurement: 'kW'
        name: 'Power Meter House'
        filters:
          - multiply: 0.06  # (60s/1000 pulses per kWh)


Counting total pulses
---------------------

When the total sensor is configured, the pulse_counter also reports the total 
number of pulses measured. When used on a power meter, this can be used to 
measure the total consumed energy in kWh. 

.. code-block:: yaml

    # Example configuration entry
    sensor:
      - platform: pulse_counter
        pin: 12
        unit_of_measurement: 'Wh'
        name: 'Power Meter House'
        filters:
          - multiply: 0.06  # (60s/1000 pulses per kWh)

        total:
          unit_of_measurement: 'kWh'
          name: 'Energy Meter House'
          filters:
            - multiply: 0.001  # (1/1000 pulses per kWh)

(Re)Setting the total pulse count
---------------------------------

Using this action, you are able to reset/set the total pulse count. This can be useful
if you would like the ``total`` sensor to match what you see on your meter you are
trying to match.

.. code-block:: yaml

    # Set pulse counter total from home assistant using this service call:
    api:
      services:
        - service: set_pulse_total
          variables:
            new_pulse_total: int
          then:
            - pulse_counter.set_total_pulses:
                id: pulse_counter_id
                value: !lambda 'return new_pulse_total;'

.. note::

    This value is the raw count of pulses, and not the value you see after the filters
    are applied.

Wiring
------

If you want to count pulses from a simple reed switch, the simplest way is to make
use of the internal pull-up/pull-down resistors.

You can wire the switch between a GPIO pin and GND; in this case set the pin to input, pullup and inverted:

.. code-block:: yaml

    # Reed switch between GPIO and GND
    sensor:
      - platform: pulse_counter
        pin:
          number: 12
          inverted: true
          mode:
            input: true
            pullup: true
        name: "Pulse Counter"

If you wire it between a GPIO pin and +3.3V, set the pin to input, pulldown:

.. code-block:: yaml

    # Reed switch between GPIO and +3.3V
    sensor:
      - platform: pulse_counter
        pin:
          number: 12
          mode:
            input: true
            pulldown: true
        name: "Pulse Counter"

The safest way is to use GPIO + GND, as this avoids the possibility of short
circuiting the wire by mistake.

See Also
--------

- :ref:`sensor-filters`
- :doc:`/components/sensor/pulse_meter`
- :doc:`rotary_encoder`
- `esp-idf Pulse Counter API <https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/pcnt.html>`__.
- :apiref:`pulse_counter/pulse_counter_sensor.h`
- :ghedit:`Edit`