Not able to read out temperature of remote CPU using HA using platform command_line

[gijssenh]

I have a HA (Home Assistant OS 5.13) running on a Raspberry PI4b. It is connected to Homebridge running on a Raspberry PI Zero. I do not succeed in reading out the temperature of the Homebridge CPU using the command_line platform. I succeed via the HA terminal using this command (no password required)

ssh root@192.168.0.245 sudo cat /sys/class/thermal/thermal_zone0/temp

Configuration.yaml:

• platform: command_line
  name: HB CPU Temp
  command: "ssh root@192.168.0.245 sudo cat /sys/class/thermal/thermal_zone0/temp"
  unit_of_measurement: "°C"
  scan_interval: 15
  value_template: '{{ value | multiply(0.001) | round(1) }}'

What can be the issue?

[pipe-2233]

Issue: command_line Sensor in Home Assistant Fails to Read Homebridge CPU Temperature

The command_line sensor configured in configuration.yaml is not working to retrieve the CPU temperature from Homebridge. The command runs correctly from Home Assistant's terminal, but the sensor does not display any data.

1. Configure Passwordless SSH Authentication

The issue might be caused by Home Assistant not having passwordless SSH authentication set up to connect to the Raspberry Pi Zero (running Homebridge). Follow these steps:

1. Access Home Assistant's terminal (e.g., via the Terminal & SSH add-on).
2. Generate an SSH key pair (if you haven’t already):

   ssh-keygen -t rsa -b 2048
   

3. Press Enter to accept the default location, and leave the passphrase blank. 3. Copy the public key to the Raspberry Pi Zero:

ssh-copy-id root@192.168.0.245

4. Verify that the connection works without a password:

ssh root@192.168.0.245

You should be able to connect without entering a password.

2. Allow sudo Without a Password on the Pi Zero

The command_line sensor uses sudo, which might still ask for a password. Here’s how to bypass it:

1. Log in to the Raspberry Pi Zero.
2. Open the sudoers file for editing:

sudo visudo

3. Add this lline at the end of the file:

root ALL=(ALL) NOPASSWD: /bin/cat /sys/class/thermal/thermal_zone0/temp

• This allows the sudo catcommand to run without asking for a password.

3. Update Your Sensor Configuration

Replace your command_line sensor in configuration.yaml with this:

sensor:
  - platform: command_line
    name: HB CPU Temp
    command: "ssh root@192.168.0.245 sudo cat /sys/class/thermal/thermal_zone0/temp"
    unit_of_measurement: "°C"
    value_template: "{{ value | multiply(0.001) | round(1) }}"

4. Test and Restart

1. Test the command in the Home Assistant terminal:

ssh root@192.168.0.245 sudo cat /sys/class/thermal/thermal_zone0/temp

if it works, restart Jome Assistant via Settings > System > Restart.

What Should Happen?

Your sensor should now display the CPU temperature of your Raspberry Pi Zero in Home Assistant.

This version keeps only the essential steps, focusing on simplicity while still being actionable.

If something else goes wrong or my solution doesn’t fix your issue completely, feel free to let me know here or reach out to me through these channels: