I think a company at this summer's YC did something similar (using wifi): http://techcrunch.com/2015/08/18/hardware-demo-day/ http://techcrunch.com/2015/08/18/

I think a company at this summer's YC did something similar (using wifi): http://techcrunch.com/2015/08/18/hardware-demo-day/ http://techcrunch.com/2015/08/18/hardware-demo-day/ ctl+f "supply"