Nested Serial Json

Currently, I am working on having serial communication between an RPI4 and Arduino Mega.

If I send an un-nested JSON message to the Pi I can see it and read it and assign it to a sensor with no issue. but as I have multiple devices I’ve decided to send nested JSON messages.

my current output is:
b1 = unavalible

Any ideas as to why the sensor data is not displaying? if I receive it unnested it is fine, just having troubles working out the correct formating for nested serial

my template looks like:

Imitate available variables:
{% set value_json = {"nest1":{"b1":36,"b2":51.51},"nest2":{"s1":-0.13,"s2":20}

'{{ value_json['nest1']['b1'] }}'
'{{ value_json['nest1']['b2'] }}'
'{{ value_json['nest2']['s1'] }}'
'{{ value_json['nest2']['s2'] }}'

which gives out:


when I look at my Developer Tools states I can see the sensor as sensor.serial_sensor which is reading state:


Displaying nicely in the attributed collum as:

b1: 36
b2: 51.51

s1: -0.13
s2: 20

Which is great because its there!

With this I’m trying to use the sensor template as follows:

  - platform: serial
    serial_port: /dev/ttyACM0
    baudrate: 9600

  - platform: template
        friendly_name: "b1"
        unit_of_measurement: "°C"
        value_template: "{{ state_attr('sensor.serial_sensor', value_json['nest1']['b1']) }}"
        friendly_name: "b2"
        unit_of_measurement: "pH"
        value_template: "{{ state_attr('sensor.serial_sensor', value_json['nest1']['b2']) }}"
        friendly_name: "s2"
        unit_of_measurement: "mg/L"
        value_template: "{{ state_attr('sensor.serial_sensor', value_json['nest2']['s2']) }}"

as per:


It’s in dev/states, so it is just a matter of syntax. Have you tried this?:

value_template: '{{ states('sensor.serial_sensor.attributes.nest1.b1') }}'

i had to make some tweaks to:
"{{ states('sensor.serial_sensor.attributes.nest1.b1') }}"

no luck but it does change the status from unavailable to unknown. will try playing around with the state attribute

Were you able to solve this issue? I have the exact same problem.