The office at DoES Liverpool has a DoorBot, which works as a kiosk device, showing webcam views of the office and a list of upcoming events.
Doorbot originally consisted of a networked PC with a flat-screen monitor facing out towards the corridor through a conveniently located window. The DoorBot works as a kiosk device, showing webcam views of the office, a list of upcoming events (from Google Calendar), and a welcome message to any expected guests.
Currently, its only input device is an RFID reader. Our members can register their RFID cards (Oyster, Walrus, DoES membership card, and so on). Finally, this device is also connected to speakers, so it can play a personalised tune or message when members check in or out. Developing this device was as simple as running software on a computer ever is: the trickiest cases are things such as turning the screen off and on after office hours and coping with losing or regaining power and network. Given how close the functionality is to that of a PC, it might seem crazy to think of any other solution. However, if we had to scale up – to cover more doors or to sell the idea to other companies – we suddenly have new trade-offs.
Just sticking a tower PC somewhere near the door may not be ideal for every office. A computer that fits neatly with an integrated screen might work, such as an iMac, a laptop, or a tablet. But these devices are much more expensive than the original commodity PC (effectively “free” when it was a one-off because it was lying around with nothing else to do). A small embedded computer, such as a Raspberry Pi, might be ideal because it costs relatively little, runs Linux and has HDMI output.
This is an edited extract from Designing the Internet of Things by Adrian McEwen and Hakim Cassimally, published by Wiley, RRP £19.99.