Monitor and regulate freezer temperature with raspberry pi. I started this project because my chest freezer's highest temperature setting is still too cold to keep my homebrew chilled, so I want to regulate the power with a relay.
There's also a little web server for serving up logs and their statistics for any given period of time. Plots can also be generated using plot.ly.
I got most of the hardware from Adafruit, including the relay and temperature sensor. They also have a really nice guide that I followed for using the sensor.
I'm running Arch linux on my pi so I haven't tested any of this with Raspbian or other distros.
Install nodejs, python 3, and RPi.GPIO. Run setup.sh as root to
configure kernel modules and install web dependencies. Then reboot the pi.
Modify controls/run.sh as needed and execute it to start the thermometer and
regulator. Similarly, edit and run web/run.sh to start the web server.
To see stats for the last 2 hours with a plot, browse to
http://<pi's IP>:8080/stats?period=2h&plot=true
Period measures are: m = minutes, h = hours, d = days, w = weeks.
If no period is given, the default is 1d.
Logs are at http://<pi's IP>:8080/logs.
The project also includes systemd service files for daemonizing the regulator and web server. Edit them as needed, then as root:
cp systemd/* /etc/systemd/system/
# start them:
systemctl start regulator-controls
systemctl start regulator-web
# make sure they're working:
systemctl status regulator-controls
systemctl status regulator-web
# to have them start at boot:
systemctl enable regulator-controls
systemctl enable regulator-web
Add pics of the UI and graphs of regulated and unregulated freezer temps.