In an effort to better proportion the heating system in his house, Mike Stirling decided to use Conrad FHT8V wireless thermostatic radiator valves (TRVs) to control heat distribution in zones. He decided to analyze the valve’s 868 MHz control signals using his RTL-SDR dongle and GNU Radio. After discovering that the protocol uses simple on-off keying (OOK), he went on to write a custom GNU Radio block to decode the packets. With this knowledge, Mike will be able to progress further toward his design of a custom home heating control system.
His efforts are a good illustration of why and how to write your own custom block in GNU Radio.
For additional details and code downloads, visit Mike’s Lab Notes website.