For the last long while, I’ve been tracking the temperature in our conservatory. This started when we had a pigeon living in there and I realised it was getting very warm during the day. Firstly, I started tracking the temperature, then I added a fan to an existing catflap to help cool the area, (then I removed the pigeon) and ultimately, the system now runs on an ESP8266 which monitors the temperature, switches the fan on for low and high temperatures (drawing air from the more thermally moderate house), provides a web interface for control and generates a status webpage using dynamically created SVG images.

An Orange Pi Nano computer is scheduled to fetch these images over the internal network every now and then, and uploads them to my website. I have been also saving the resultant 24 hour plots for each (most – I’ve had a couple of power and or internet outages) day.

The current status (near live) can be found here.

Historic data is crudely stored here (I need to add pages, possibly automatically because I’m lazy. I think I worked out how at the time (show number ranges x through y, multiples… something like that. Perhaps need to learn how to pass parameters to php as I don’t really do internet stuff), but never implemented it.

In the future, I plan on modifying the code to reduce the work done by the ESP8266 to just fan control and temperature logging, with more of the intelligence / image generation offloaded to the Orange Pi Linux SBC. I will then consider creating more sensor nodes, using sleep functions to minimise power consumption to a level suitable for battery and / or solar power and ultimately, put other sensors around the house and in the garden shed.

Temperatures in the house might enable me to control our central heating boiler in a more intelligent fashion than it already is, while the garden shed would be a good source of the ambient temperature in our location (handy for passive cooling with ambient air for example, using fans fitted to the fresh air bricks in the house).