subtlepseudonym / kegerator

For monitoring keg metadata like drink type and amount of drink remaining

Kegerator

This project utilizes a raspberry pi zero w and a flow meter to monitor keg levels

Running this project

docker create \
	--name kegerator \
	--publish 9220:9220 \
	--device /dev/gpiomem \
	--volume "/sys/class/gpio:/sys/class/gpio" \
	--volume "/sys/devices/platform/soc/20200000.gpio/gpiochip0:/sys/devices/platform/soc/20200000.gpio/gpiochip0" \
	--volume "path-to-directory-containing-state.json:/data" \
	subtlepseudonym/kegerator:latest
docker start kegerator

The path to /sys/devices/platform/... may be incorrect for your system. If this is the case, you can run the following to obtain the correct path:

echo 1 >> /sys/class/gpio/export
ls -l /sys/class/gpio/gpio1

Known issues

• Permissions for /sys/class/gpio/gpioX are not set correctly
  • They should be root:gpio, but are root:root
  • The workaround for this is included in the command above by mounting /sys/devices/platform/...
• Flow meter pins are not correctly detached on shutdown
  • For example, using pin 14, /sys/class/gpio/gpio14 will persist after the container has been stopped
  • Current workarounds:
    • run outside of a docker container
    • run echo 14 >> /sys/class/gpio/unexport after stopping the container

Dependency modifications

This is a list of dependency modifications to help this project run a bit better. Relevant entries will be removed if the project moves to vendored dependencies.

• github.com/d2r2/go-dht
  • logger.go: logging level changed to Error
  • gpio.h: uncommented sleep between /sys/class/gpio/export write and /sys/class/gpio/gpioX/direction write
• udev rules on raspi
  • SUBSYSTEM="gpio", ACTION="add", PROGRAM="/bin/sh -c 'chgrp -R gpio /sys%p && chmod -R 770 /sys%p'"
  • This solves the permissions issue mentioned above when the binary is run natively