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163 lines
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163 lines
6.5 KiB
ReStructuredText
ESP32 Touch Pad
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===============
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.. seo::
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:description: Instructions for setting up the touch pad on the ESP32.
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:image: touch.png
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.. _esp32-touch-component:
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Component/Hub
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-------------
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The ``esp32_touch`` component creates a global hub for detecting touches on
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the eight touch pads of the ESP32 as :ref:`binary senors <esp32-touch-binary-sensor>`.
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.. code-block:: yaml
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# Example configuration entry
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esp32_touch:
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setup_mode: False
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binary_sensor:
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- platform: esp32_touch
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name: "ESP32 Touch Pad GPIO27"
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pin: GPIO27
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threshold: 1000
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Configuration variables:
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************************
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- **setup_mode** (*Optional*, boolean): Whether debug messages with the touch pad value should
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be displayed in the logs. Useful for finding out suitable thresholds for the binary sensors, but
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spam the logs. See :ref:`setting up touch pads <esp32-touch-binary-sensor>`
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for more information. Defaults to false.
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- **id** (*Optional*, :ref:`config-id`): Manually specify the ID for code generation.
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Advanced options (the defaults are usually quite good, but if you're having accuracy issues, use these):
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- **iir_filter** (*Optional*, :ref:`config-time`): Optionally set up an
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`Infinite Impulse Response <https://en.wikipedia.org/wiki/Infinite_impulse_response>`__
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filter should be applied to all touch pads. This can increase the accuracy of the touch pads a lot, but
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higher values decrease the response time. A good value to start with is ``10ms``. Default is no IIR filter.
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- **sleep_duration** (*Optional*, :ref:`config-time`): Set a time period
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denoting the amount of time the touch peripheral should sleep between measurements. This can decrease
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power usage but make the sensor slower. Default is about 27 milliseconds.
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- **measurement_duration** (*Optional*, :ref:`config-time`): Set the conversion
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time for all touch pads. A longer conversion time means that more charge/discharge cycles of the touch pad
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can be performed, therefore increasing accuracy. Default is about 8ms, the maximum amount.
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- **low_voltage_reference** (*Optional*): The low voltage reference to use for the charge cycles. See
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the `esp-idf docs <https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/touch_pad.html#optimization-of-measurements>`__
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for a nice explanation of this. One of ``0.5V``, ``0.6V``, ``0.7V``, ``0.8V``. Default is ``0.5V``.
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- **high_voltage_reference** (*Optional*): The high voltage reference to use for the charge cycles. See
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the `esp-idf docs <https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/touch_pad.html#optimization-of-measurements>`__
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for a nice explanation of this. One of ``2.4V``, ``2.5V``, ``2.6V``, ``2.7V``. Default is ``2.7V``.
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- **voltage_attenuation** (*Optional*): The voltage attenuation to use for the charge cycles. See
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the `esp-idf docs <https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/touch_pad.html#optimization-of-measurements>`__
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for a nice explanation of this. One of ``1.5V``, ``1V``, ``0.5V``, ``0V``. Default is ``0V``.
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.. _esp32-touch-binary-sensor:
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Binary Sensor
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-------------
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The ``esp32_touch`` binary sensor platform lets you use the touch peripheral of the
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ESP32 to detect if a certain pin is being "touched".
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First, you need to setup the :ref:`global touch hub <esp32-touch-component>`. Then
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you can add individual touch pads as binary sensors. When a touch is detected on these pins, the binary
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sensor will report an ``ON`` state. And, of course, if no touch is detected, the binary sensor will report
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an ``OFF`` state.
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.. figure:: images/esp32_touch-ui.png
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:align: center
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:width: 80.0%
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.. code-block:: yaml
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# Example configuration entry
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esp32_touch:
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binary_sensor:
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- platform: esp32_touch
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name: "ESP32 Touch Pad GPIO27"
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pin: GPIO27
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threshold: 1000
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Configuration variables:
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************************
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- **pin** (**Required**, :ref:`config-pin`): The pin to detect touch
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events on.
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- **threshold** (**Required**, int): The threshold to use to detect touch events. Smaller values mean
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a higher probability that the pad is being touched.
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- **name** (**Required**, string): The name of the binary sensor.
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- **id** (*Optional*,
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:ref:`config-id`): Manually specify
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the ID used for code generation.
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- All other options from :ref:`Binary Sensor <config-binary_sensor>`.
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Touch Pad Pins
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--------------
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8 pins on the ESP32 can be used to detect touches. These are (in the default "raw" pin names):
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- ``GPIO0``
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- ``GPIO2``
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- ``GPIO4``
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- ``GPIO12``
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- ``GPIO13``
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- ``GPIO14``
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- ``GPIO15``
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- ``GPIO27``
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- ``GPIO32``
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- ``GPIO33``
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Finding thresholds
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------------------
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For each touch pad you want to monitor, you need to find a threshold first. This threshold is
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used to determine if a pad is being touched or not using the raw values from the sensor. Lower
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raw values mean that it is more likely that a touch is happening. For example, values around
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1000 to 1600 usually mean the pad is not being touched, and values in the range of 600 and less
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mean the pad is probably being touched.
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To find suitable threshold values, first configure the :ref:`ESP32 touch hub <esp32-touch-component>`
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to output measured values using the ``setup_mode:`` configuration option. Next, add some binary sensors
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for the touch pads you want to observe. Also put some threshold in the configuration as seen below
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to make the validator happy, we are going to find good thresholds in a moment anyway.
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.. code-block:: yaml
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# Example configuration entry for finding threshold values
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esp32_touch:
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setup_mode: True
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binary_sensor:
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- platform: esp32_touch
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name: "ESP32 Touch Pad GPIO27"
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pin: GPIO27
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threshold: 1000
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Then upload the program and open the logs, you will see values like these. Try touching the pins
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and you will (hopefully) see the value decreasing a bit. Play around with different amounts of
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force you put on the touch pad until you find a good value that can differentiate between
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touch/non-touch events.
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.. figure:: images/esp32_touch-finding_thresholds.png
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:align: center
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Finally, put your threshold parameter in the configuration. Do not forget to disable the ``setup_mode``
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option again by setting it to ``False``. Otherwise you will end up spamming the logs and slowing the device
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down.
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See Also
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--------
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- :doc:`/components/binary_sensor/index`
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- :apiref:`binary_sensor/esp32_touch_binary_sensor.h`
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- `esp-idf Touch Sensor API <https://esp-idf.readthedocs.io/en/latest/api-reference/peripherals/touch_pad.html>`__
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- :ghedit:`Edit`
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.. disqus::
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