esphome-docs/cookbook/display_time_temp_oled.rst
2021-05-20 16:00:53 +02:00

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Time & Temperature on OLED Display
==================================
.. seo::
:description: Instructions for setting up a display in ESPHome to show sensor values from Home Assistant
:image: display_time_temp_oled_1.jpg
:keywords: Display
.. figure:: images/display_time_temp_oled_1.jpg
:align: left
:width: 75.0%
In this example I have used a :doc:`SSD1306 OLED Display over I²C </components/display/ssd1306>` to
show current time and two different temperature values from Home Assistant.
ESPHome has support for several different types of displays. The display used here is 1.3" with 128x64 monochrome pixels (``SH1106 128x64``).
Hardware configuration
----------------------
Hardware is easy! Only four connections are needed:
- ``VCC`` - Power (my display could use either 3.3V or 5V)
- ``GND`` - Ground
- ``SDA`` - Serial Data
- ``SCL`` - Serial Clock
.. warning::
Ensure your display handles 5V if you use that.
Software configuration
----------------------
Getting Time
************
Get the time from Home Assistant to sync the onboard real-time clock.
.. code-block:: yaml
time:
- platform: homeassistant
id: esptime
Getting Temperature
*******************
Next, we want to get two temperature sensors imported from Home Assistant.
I named them ``inside_temperature`` and ``outside_temperature``. You will use those references later.
By adding ``internal: true`` to the sensors they won't be published back to Home Assistant.
.. code-block:: yaml
sensor:
- platform: homeassistant
id: inside_temperature
entity_id: sensor.mellanvaning_temperature
internal: true
- platform: homeassistant
id: outside_temperature
entity_id: sensor.10_00080192969d_temperature
internal: true
Define the Fonts
****************
- TrueType fonts are used. If you ever worked with fonts on microcontrollers you will love this!
- Save font files in ``/config/esphome`` folder where your ESPHome configuration is stored.
- The ``.ttf`` suffix must be lowercase and of course match your filename.
- Selection of fonts can be a little bit tricky for small sizes to look good. Experiment and share your findings in the comments below!
.. code-block:: yaml
font:
- file: 'slkscr.ttf'
id: font1
size: 8
- file: 'BebasNeue-Regular.ttf'
id: font2
size: 48
- file: 'arial.ttf'
id: font3
size: 14
Display Definition
******************
Now setup the communication to the display and start fill the screen with live data!
The ``reset_pin`` was not used in my hardware configuration as the display didn't have that pin exposed.
Note your ``address`` and ``model`` might be different, use the scan option to find the address of your display.
.. code-block:: yaml
i2c:
sda: D1
scl: D2
scan: False
display:
- platform: ssd1306_i2c
model: "SH1106 128x64"
reset_pin: D0
address: 0x3C
lambda: |-
// Print "Mitt Smarta Hus" in top center.
it.printf(64, 0, id(font1), TextAlign::TOP_CENTER, "Mitt Smarta Hus");
// Print time in HH:MM format
it.strftime(0, 60, id(font2), TextAlign::BASELINE_LEFT, "%H:%M", id(esptime).now());
// Print inside temperature (from homeassistant sensor)
if (id(inside_temperature).has_state()) {
it.printf(127, 23, id(font3), TextAlign::TOP_RIGHT , "%.1f°", id(inside_temperature).state);
}
// Print outside temperature (from homeassistant sensor)
if (id(outside_temperature).has_state()) {
it.printf(127, 60, id(font3), TextAlign::BASELINE_RIGHT , "%.1f°", id(outside_temperature).state);
}
Rendering
---------
- Alignment of text can use different reference points, for example ``TOP_RIGHT`` or ``BASELINE_LEFT``, which all are defined in :apiref:`display/display_buffer.h`.
- The property ``has_state()`` on a sensor is useful as it can take some seconds to get the data from Home Assistant and you may not want to display ``Nan``
- Refer to the rendering engine :ref:`display-engine` for more features (it can draw lines and circles too!)
Add a Text-Based Sensor
-----------------------
Below follows an example that replaces the "Mitt smarta hem" top printout with the alarm status from the alarm component in Home Assistant.
.. code-block:: yaml
text_sensor:
- platform: homeassistant
entity_id: alarm_control_panel.my_alarm_system
name: "Alarm State"
id: alarm_state
display:
- platform: ssd1306_i2c
model: "SH1106 128x64"
reset_pin: D0
address: 0x3C
lambda: |-
// Print "Alarm State: <state>" in top center
it.printf(64, 0, id(font1), TextAlign::TOP_CENTER, "Alarm State: %s", id(alarm_state).state.c_str());
See Also
--------
- :doc:`/components/display/ssd1306`
- :doc:`/components/display/index`
- :doc:`/components/sensor/homeassistant`
- :ghedit:`Edit`