esphome-docs/components/sensor/ads1115.rst
Ockert Marais e95c4133c3
Update ads1115.rst Multiplexer and Gain (#1232)
Update ads1115.rst notes with gentle warning about over voltage measurement which is not entirely clear at first sight / observation of the sensor.
2021-06-11 15:32:10 +12:00

134 lines
4.4 KiB
ReStructuredText

ADS1115 Sensor
==============
.. seo::
:description: Instructions for setting up ADS1115 multiplexed analog voltage sensors.
:image: ads1115.jpg
:keywords: ADS1115
.. _ads1115-component:
Component/Hub
-------------
The ``ads1115`` domain creates a global hub so that you can later create
individual sensors using the :ref:`ADS1115 Sensor Platform <ads1115-sensor>`.
To use this hub, first setup the :ref:`I²C Bus <i2c>` and connect the sensor to the pins specified there.
.. figure:: images/ads1115-full.jpg
:align: center
:width: 50.0%
ADS1115 16-Bit ADC.
.. _Adafruit: https://www.adafruit.com/product/1085
.. code-block:: yaml
ads1115:
- address: 0x48
Configuration variables:
************************
- **address** (**Required**, int): The i²c address of the sensor.
See :ref:`I²C Addresses <ads1115_i2c_addresses>` for more information.
- **continuous_mode** (*Optional*, boolean): Set if the ADS1115 should continuously measure voltages or
only measure them when an update is called. Please enable this for the :doc:`ct_clamp` integration.
Defaults to ``off``.
- **id** (*Optional*, :ref:`config-id`): Manually specify the ID for this ADS1115 Hub. Use this if you
want to use multiple ADS1115 hubs at once.
.. _ads1115_i2c_addresses:
I²C Addresses
-------------
In order to allow multiple sensors to be connected to the same i²c bus,
the creators of this sensor hardware have included some options to
change the i²c address.
- If the address pin is pulled to GND, the address is ``0x48`` (Default).
- If the address pin is pulled to VCC, the address is ``0x49``.
- If the address pin is tied to SDA, the address is ``0x4a``.
- If the address pin is tied to SCL, the address is ``0x4B``.
.. _ads1115-sensor:
Sensor
------
The ``ads1115`` sensor allows you to use your ADS1115 sigma-delta ADC
sensors (`datasheet <http://www.ti.com/lit/ds/symlink/ads1115.pdf>`__, `Adafruit`_) with ESPHome.
First, setup an :ref:`ADS1115 Hub <ads1115-component>` for your ADS1115 sensor and then use this
sensor platform to create individual sensors that will report the
voltage to Home Assistant.
.. _Adafruit: https://www.adafruit.com/product/1085
.. figure:: images/ads1115-ui.png
:align: center
:width: 80.0%
.. code-block:: yaml
ads1115:
- address: 0x48
sensor:
- platform: ads1115
multiplexer: 'A0_GND'
gain: 6.144
name: "ADS1115 Channel A0-GND"
Configuration variables:
************************
- **multiplexer** (**Required**): The multiplexer channel of this sensor. Effectively means between which pins you
want to measure voltage.
- **gain** (**Required**, float): The gain of this sensor.
- **name** (**Required**, string): The name for this sensor.
- **ads1115_id** (*Optional*, :ref:`config-id`): Manually specify the ID of the
:ref:`ADS1115 Hub <ads1115-component>` you want to use this sensor.
- **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.
Multiplexer and Gain
--------------------
.. note::
As per (`datasheet <http://www.ti.com/lit/ds/symlink/ads1115.pdf>`__, `Adafruit`_) Section 7.3 Note 2:
"No more than VDD + 0.3V must be applied to the analog inputs of the device."
This means if you power the device with 3.3V, take care not to supply the 4 AIN pins with more than 3.6V.
The ADS1115 has a multiplexer that can be configured to measure voltage between several pin configurations. These are:
- ``A0_A1`` (between Pin 0 and Pin 1)
- ``A0_A3`` (between Pin 0 and Pin 3)
- ``A1_A3`` (between Pin 1 and Pin 3)
- ``A2_A3`` (between Pin 2 and Pin 3)
- ``A0_GND`` (between Pin 0 and GND)
- ``A1_GND`` (between Pin 1 and GND)
- ``A2_GND`` (between Pin 2 and GND)
- ``A3_GND`` (between Pin 3 and GND)
Additionally, the ADS1115 has a Programmable Gain Amplifier (PGA) that can help you measure voltages in different ranges, these are:
- ``6.144`` (measures up to 6.144V)
- ``4.096`` (measures up to 4.096V)
- ``2.048`` (measures up to 2.048V)
- ``1.024`` (measures up to 1.024V)
- ``0.512`` (measures up to 0.512V)
- ``0.256`` (measures up to 0.256V)
See Also
--------
- :ref:`sensor-filters`
- :doc:`adc`
- :doc:`max6675`
- :apiref:`ads1115/ads1115.h`
- `i2cdevlib <https://github.com/jrowberg/i2cdevlib>`__ by `Jeff Rowberg <https://github.com/jrowberg>`__
- :ghedit:`Edit`