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A Google engineer has developed a solar-powered data display for Google calendar information to use as signage in Google’s offices outside of their conference rooms (to display meeting schedules). It uses an ultra lower-power Cholesteric LCD display which can operate on energy generated from indoor light. Aaron Spangler, the engineer, claims on the video that Google uses six reams of paper, in 2200 conference rooms, every single day. So, given that, and the people-power required to change and update the signs, this is a significant time and money saver. Besides the Cholesteric display, the unit uses a PIC-based MCU and a Xbee wireless module.

Radish – Indoor Solar-powered Calendar Display

Gareth Branwyn

Gareth Branwyn

Gareth Branwyn is a freelancer writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor for Boing Boing and WINK Books. And he has a new best-of writing collection and “lazy man’s memoir,” called Borg Like Me.


  • Eric

    People at google dont have laptops to look at what rooms are booked and to book rooms? I work at a fortune 50 company and we just use outlook with rooms to see who has a room, when, and book it when we want it. Seams a much simpler solution to just use the laptop you have with you.

  • fiji [limey.net]

    I found the Kent Electronics site, but saw no prices…

  • Jack Biggs

    Don’t you mean 2200 conference rooms?

    • Gareth Branwyn

      @ Jack Biggs
      Yes, thanks for the catch, Jack!

  • Jim Parker

    This is a great project that has some interesting characteristics — very low power use, indoor solar with capacitor storage, and an unusual LCD display.

    Any chance that Make could help the rest of us get information on the parts list/sources and or a schematic?

    I’d really like that. Thanks.

  • Low Power Display Market

    Hey, Gr8 discovery, where do we get these devices.