Home Assistant using the Home Assistant Operating System which is a managed environment, which means you can’t use existing methods to enable the I2C bus on a Raspberry Pi. In order to use I2C devices you will have to
- Enable I2C for the Home Assistant Operating System
- Setup I2C devices e.g. sensors
- You will need:
- SD card reader
- SD card with Home Assistant Operating System flashed on it
Shutdown/turn-off your Home Assistant installation and unplug the SD card. Plug the SD card into an SD card reader and find a drive/file system named hassos-boot. The file system might be shown/mounted automatically. If not, use your operating systems disk management utility to find the SD card reader and make sure the first partition is available.
- In the root of the hassos-boot partition, add a new folder called CONFIG.
- In the CONFIG folder, add another new folder called modules.
- Inside the modules folder add a text file called rpi-i2c.conf with the following content:
i2c-dev
- In the root of the hassos-boot partition, edit the file called config.txt add two lines to it:
dtparam=i2c_vc=on
dtparam=i2c_arm=on
- Insert the SD card back into your Raspberry Pi.
- On startup, the hassos-config.service will automatically pickup the new rpi-i2c.conf configuration.
- Another reboot might be necessary to make sure the just imported rpi-i2c.conf is present at boot time.
Argon One Active Cooling Repository Here:
My settings:
CorF : C
LowRange: 35
MediumRange: 45
HighRange: 50
Alternatively, by attaching a keyboard and screen to your device, you can access the physical terminal to the Home Assistant Operating System.
- Login as root.
- Type login and press enter to access the shell.
- Type the following to enable I2C, you may need to replace sda1 with sdb1 or mmcblk0p1 depending on your platform:
mkdir /tmp/mnt
mount /dev/sda1 /tmp/mnt
mkdir -p /tmp/mnt/CONFIG/modules
echo -ne i2c-dev>/tmp/mnt/CONFIG/modules/rpi-i2c.conf
echo dtparam=i2c_vc=on >> /tmp/mnt/CONFIG/config.txt
echo dtparam=i2c_arm=on >> /tmp/mnt/CONFIG/config.txt
sync
reboot
After rebooting the host there should be i2c-0 and similar device files in /dev. If such device files are missing, enabling I2C failed for some reason. You can check the status of I2C kernel modules by using lsmod | grep i2c in the terminal. If they are loaded, you should find at least the entry i2c_dev.
Active usage of the modules is indicated by a number, e.g. i2c_dev 20480 2 would indicate two active I2C device files.
An active I2C can also be checked with a multi meter showing 3.3 V on the I2C pins GPIO2 and GPIO3.