Read json as sensor value

Configuration
1

Hello, I am trying to read some sensor values of my Arduino with serial communication. To do this I used the example with the Json given here: https://www.home-assistant.io/integrations/serial/

The data seems to be coming in fine: image

To assign the data to a sensor I tried the following:


sensor:
  - platform: serial
    serial_port: /dev/ttyUSB0
    baudrate: 9600
    
  - platform: template
    sensors:
        my_pressure_sensor:
         friendly_name: Pressure 
         unit_of_measurement: "mbar"
         value_template: "{{ value_json.norm }}"'

When I add the sensor to my dashboard is says its unavailable. I found some similar post but can’t quite figure it out.

2

You need to use the state of your serial sensor in the value_template.

value_template: "{{ states('sensor.serial_sensor').norm }}"

Take a look in Dev tools/states for the entity_id.
You can play with the template in Dev tools/templates.

2 Likes
3

I have been playing with the template a bit
When I use :

value_template: "{{ states('sensor.serial_sensor') }}"

I get the following result:

value_template: "{"norm":1000.11,"hg":0.59,"temp":22.394,"alarmOn":0,"status":1,"counter":19}"

when I add any of the dot entity_id I get :

value_template: ""

I don’t understand why it does not show me the value

4

Please post a screenshot of the result if you use:

{{ states('sensor.serial_sensor') }}

Auswahl_424
Auswahl_424959×207 19 KB

5

image
image1388×552 22.7 KB

6

Hmm, i waited for the ‘Result type:’ like in my picture, but it looks like a string.
What version af HA are you running?

Another aproach:
The serial sensor has a value_template option built in.
What about:

sensor:
  - platform: serial
    serial_port: /dev/ttyUSB0
    baudrate: 9600
    value_template: "{{ value_json.norm }}"

without an extra template sensor?

7

I am running version 0.115.6 the result type doesn’t show up.
The value template within the serial sensor works. However, I don’t know how I can extract multiple values this way.

8

I don’t know if it’s possible to create multiple serial sensors that way.

The template sensors should be possible by splitting the returned string from the serial sensor (without the value_template).
What does

{{ states('sensor.serial_sensor').split(',')[0].split(':')[1] }}

in the template tool?

9

Thank you very much for your help, this method works!