After months of decent reliability from the Roast Genie, the SD card in the Raspberry Pi became corrupted one too many times. I am going change the architecture of the system to eliminate the Pi. Even though I had implemented a robust shutdown routine, the Pi proved not to be up to the task. I’ve seen some write-ups on RasPi applications that use a write protected SD card with a USB thumb drive for a R/W file system but frankly, I have had it with the Pi in this application.
I am now working on an alternative approach that should be considerably more robust. This system will be based on ATMEGA hardware (Arduino) that has proven to be very robust and the Adafruit Huzzah for cheap WiFi and IoT connectivity. Proof of concept is working now but it will be a while before I am posting new roast plots.
I will post details of the build later.