esphome-docs/components/display/tm1637.rst

TM1637 7-Segment Display
========================

.. seo::
    :description: Instructions for setting up TM1637 7-segment displays.
    :image: tm1637.jpg

The ``tm1637`` display platform allows you to use the popular TM1637 7-segment display drivers with ESPHome.

.. figure:: images/tm1637-full.jpg
    :align: center
    :width: 75.0%

    TM1637 7-Segment Display.

The module can be powered with 5v or with 3.3v too. To display the colon punctiation use the
``.`` in the colon place. (See clock example below)


.. code-block:: yaml

    # Example configuration entry
    display:
        platform: tm1637
        id: tm1637_display
        clk_pin: D6
        dio_pin: D5
        lambda: |-
          it.print("0123");


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

- **clk_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): The pin you have the CLK line hooked up to.
- **dio_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): The pin you have the DIO line hooked up to.
- **intensity** (*Optional*, integer): The intensity with which the TM1637 should drive the outputs. Range is from
  0 (least intense) to 7 (the default).
- **lambda** (*Optional*, :ref:`lambda <config-lambda>`): The lambda to use for rendering the content on the TM1637.
  See :ref:`display-tm1637_lambda` for more information.
- **update_interval** (*Optional*, :ref:`config-time`): The interval to re-draw the screen. Defaults to ``1s``.
- **id** (*Optional*, :ref:`config-id`): Manually specify the ID used for code generation.

.. _display-tm1637_lambda:

Rendering Lambda
----------------

The TM1637 has a similar API to the fully fledged :ref:`display-engine`, but it's only a subset as the TM1637
7-segment displays don't have a concept of individual pixels. In the lambda you're passed a variable called ``it``
as with all other displays. In this case however, ``it`` is an TM1637 instance (see API Reference).

The most basic operation with the TM1637 is wiring a simple number to the screen as in the configuration example
at the top of this page. But even though you're passing in a string (here ``"0123"``), ESPHome converts it
into a representation that the TM1637 can understand: The exact pixels that should be turned on. And of course,
not all characters can be represented. You can see a full list of characters :ref:`at the MAX7219 docs <display-max7219_characters>`.

Each of the three methods (``print``, ``printf`` and ``strftime``) all optionally take a position argument at the
beginning which can be used to print the text at a specific position. This argument is ``0`` by default which
means the first character of the first TM1637. For example to start the first character of your text at
the end of the TM1637, you would write ``it.print(3, "0");``.

Also note that the ``.`` (dot) character is special because when ESPHome encounters it in the string the dot
segment of the previous position will be enabled.

.. code-block:: yaml

    display:
      - platform: tm1637
        # ...
        lambda: |-
          // Print 0 at position 0 (left)
          it.print("0");
          // Result: "0   "

          // Print 1 at position 1 (second character)
          it.print(1, "1");
          // Result: "01  "

          // Let's write a sensor value (let's assume it's 42.1)
          it.printf(0, "%.1f", id(my_sensor).state);
          // Result: "42.1 " (the dot will appear on the "2" segment)

          // Overwrite the previous content with blank
          it.print("    ");
          // Print a right-padded sensor value with 0 digits after the decimal
          it.printf("S%3.0f", id(my_sensor).state);
          // Result: "S 42"

          // Print the current time
          it.strftime("%H.%M");
          // Result for 10:06:42 -> "10:06" on a display with : and "10.06" on a display with .

Please see :ref:`display-printf` for a quick introduction into the ``printf`` formatting rules and
:ref:`display-strftime` for an introduction into the ``strftime`` time formatting.

Creating a digital clock
************************

The following example creates a typical digital clock with the ``:`` colon flashing every second.


.. code-block:: yaml


    time:
      - platform: homeassistant
        id: homeassistant_time

    display:
      platform: tm1637
      clk_pin: D6
      dio_pin: D5
      update_interval: 500ms
      lambda: |-
          static int i = 0;
          i++;
          if ((i % 2) == 0)
            it.strftime("%H.%M", id(homeassistant_time).now());
          else
            it.strftime("%H%M", id(homeassistant_time).now());


See Also
--------

- :doc:`index`
- :apiref:`tm1637/tm1637.h`
- `TD1637 Library <https://github.com/avishorp/TM1637>`__ by `Avishay <https://github.com/avishorp>`__
- :ghedit:`Edit`