I started my datalogger before seeing other pages here. I've published my code at: github.com/Pete-C2/Multi-Channel-Temperature-Monitor. It should work fine (I've been trying it indoors so far) and while I intend to make a few more changes it seems to work fine. It uses a Raspberry Pi and MAX31855K ICs to monitor temperature. I only have two channels so far but intend to have twelve eventually. One day I might have an Android App (don't hold your breath but it's something I'd like to have in place, interacting with a smartwatch to provide alarms, for example using a probe in meat to indicate when the meat is just right).