I saw this today thought it was interesting.
www.element14.com/community/groups/energy-harvesting-solutions/blog/2013/05/13/taking-a-break-from-brewing-for-growingelement14 member Sean Reynolds Massey-Reed of Australia created a homebrew monitoring kit powered by excess heat generated during the fermentation process. The attached sensors monitor how much power the kit uses to gauge the potential of operating on that excess heat. Eventually, Massey-Reed aims to use more testing and sensors so the monitor can track the entire brewing process -- mash temperature, time until boil, time to cool, fermentation temperature, and pH levels -- using only heat