This is a long due project using a raspberry Pi to monitor the temperature of a cabin I've been building for a very long time. I've bought the hardware almost 4 years ago and only arrived to the point where I could use it.
Beside the geek motivation the main practical motivation is to measure inside and outside temperature in order to estimate:
- degree of insulation and week points
- min temperature in order to calculate needed anti-freeze mix for heating pipes
- temperature monitoring for pump automation (TODO)
- min temperature in order to start some electric heating (TODO)
- accuracy of weather predictions for the location
The architecture of the system is quite simple and has the following components:
- the raspberry PI, model B which uses several DS18B20 sensors to monitor temperature
- the piBot (this project) which is basicaly a main loop with sensors and output plugins
- the vpn client over 3G in order to ensure connectivity in the lack of a fixed ip
- the vpn server and db where data is stored
- the visualisation which uses (grafana)[https://grafana.com/] with a pgsql backend
PiBot is a python main loop which has a plugin mechanism for sensors and outputs. Currently I implemented:
- sensor: ds18b20 which reads /sys/bus/w1/devices/%s/w1_slave data (sensor integration is present in the raspbian)
- sensor: /sys/class/thermal/*/temp temperature for CPU temperature
- sensor: dht22 which reads temperature and humidity
- output: csv plain output
- output: postgresql output in grafana friendly format
- trigger: starts a relay when the temperature is above a certain value to start a recirculating pump and stops the relay when the temperature is below a certain value
