Harald Haas: Wireless data from every light bulb | Video on TED.com:

What if every light bulb in the world could also transmit data? At TEDGlobal, Harald Haas demonstrates, for the first time, a device that could do exactly that. By flickering the light from a single LED, a change too quick for the human eye to detect, he can transmit far more data than a cellular tower — and do it in a way that’s more efficient, secure and widespread.