home-assistant.io/source/_integrations/serial.markdown

title	description	ha_category	ha_release	ha_iot_class	ha_codeowners	ha_domain	ha_platforms	ha_integration_type
Serial	Instructions on how to integrate data from serial connected sensors into Home Assistant.	Sensor	0.56	Local Polling	@fabaff	serial	sensor	integration

The serial sensor {% term integration %} is using the data provided by a device connected to the serial port of the system where Home Assistant is running. With ser2net and socat would it also work for sensors connected to a remote system.

To check what kind of data is arriving at your serial port, use a command-line tool like minicom or picocom on Linux, on a macOS you can use screen or on Windows putty.

sudo minicom -D /dev/ttyACM0

Configuration

To setup a serial sensor to your installation, add the following to your {% term "configuration.yaml" %} file. {% include integrations/restart_ha_after_config_inclusion.md %}

# Example configuration.yaml entry
sensor:
  - platform: serial
    serial_port: /dev/ttyACM0

{% configuration %} serial_port: description: Local serial port where the sensor is connected and access is granted. required: true type: string name: description: Friendly name to use for the frontend. Default to "Serial sensor". required: false type: string baudrate: description: Baudrate of the serial port. required: false default: 9600 Bps type: integer bytesize: description: "Number of data bits. Possible values: 5=FIVEBITS, 6=SIXBITS, 7=SEVENBITS, 8=EIGHTBITS." required: false default: 8 type: integer parity: description: "Enable parity checking. Possible values: N=PARITY_NONE, E=PARITY_EVEN, O=PARITY_ODD, M=PARITY_MARK, S=PARITY_SPACE." required: false default: "N" type: string stopbits: description: "Number of stop bits. Possible values: 1=STOPBITS_ONE, 1.5=STOPBITS_ONE_POINT_FIVE, 2=STOPBITS_TWO." required: false default: 1 type: float xonxoff: description: Enable software flow control. required: false default: False type: boolean rtscts: description: Enable hardware (RTS/CTS) flow control. required: false default: False type: boolean dsrdtr: description: Enable hardware (DSR/DTR) flow control. required: false default: False type: boolean value_template: description: "Defines a template to extract a value from the serial line." required: false type: template {% endconfiguration %}

value_template for Template sensor

TMP36

{% raw %}

"{{ (((states('sensor.serial_sensor') | float * 5 / 1024 ) - 0.5) * 100) | round(1) }}"

{% endraw %}

Examples

Arduino

For controllers of the Arduino family, a possible sketch to read the temperature and the humidity could look like the sample below.The returned data is in JSON format and can be split into the individual sensor values using a template.

#include <ArduinoJson.h>

void setup() {
  Serial.begin(115200);
}

void loop() {
  StaticJsonDocument<100> jsonBuffer;

  jsonBuffer["temperature"] = analogRead(A0);
  jsonBuffer["humidity"] = analogRead(A1);

  serializeJson(jsonBuffer, Serial);
  Serial.println();
  
  delay(1000);
}

Devices returning multiple sensors as a text string

For devices that return multiple sensors as a concatenated string of values with a delimiter, (i.e., the returned string is not JSON formatted) you can make several template sensors, all using the same serial response. For example, a stream from the Sparkfun USB Weather Board includes temperature, humidity and barometric pressure within it returned text string. Sample returned data:

$,24.1,50,12.9,1029.83,0.0,0.00,*
$,24.3,51,12.8,1029.76,0.0,0.00,*

To parse this into individual sensors, split using the comma delimiter and then create a template sensor for each item of interest.

{% raw %}

# Example configuration.yaml entry
sensor:
  - platform: serial
    serial_port: /dev/ttyUSB0
    baudrate: 9600

template:
  sensor:
    - name: Temperature
      unit_of_measurement: "°C"
      state: "{{ states('sensor.serial_sensor').split(',')[1] | float(default=0) }}"
    - name: Humidity
      unit_of_measurement: "%"
      state: "{{ states('sensor.serial_sensor').split(',')[2] | float(default=0) }}"
    - name: Barometer
      unit_of_measurement: "mbar"
      state: "{{ states('sensor.serial_sensor').split(',')[4] | float(default=0) }}"

{% endraw %}

Digispark USB Development Board

This blog post describes the setup with a Digispark USB Development Board.