Currently, for reasons unknown, the door sensors are non-functioning. Why not try the webcams instead? (May 2011)

The reason, at least at current, is that they no longer exist. Please check the webcams as above. (March 2022)

Pictorial schematic - Click to enlarge

The New New Door Sensors:

Want to know if the UCC is open? The open/closed status of various doors in the clubroom and Cameron Hall can be checked online!

Through the Web

Check out our (simple) web interface at

Through finger

At a command line on a UCC machine (or elsewhere on the internet), type:

finger [email protected]

Through Jabber/XMPP

Fire up your favourite Jabber instant messaging client, such as Pidgin, Empathy or Google Talk. If you don't have an account somewhere, register a user on Then, simply add the following as friends:

Pictorial schematic - Click to enlarge Annotated photo - Click to enlarge

How They Work:

Currently the door sensors use reed switches plugged into a DECserver which we probe over LAT by sending serial characters down the line. If our serial characters are returned to us, because the circuit is complete, the reed switch is in its closed position. Using a Python and D-BUS based solution, various interfaces can query the status. For example, the Jabber client changesthe status of the appropriate user based on the condition of the door. An online user represents an open door and an away user a closed one.

Much of the software involved is available from the UCC's uccdoor source code repository.

Who Was Responsible:

Most of the hardware work on the current door status system was completed in late 2004 by Mark Tearle and Davyd Madeley. The first iteration of the software side of things was handled later with a combined effort from Bernard Blackham, Mark Tearle and Grahame Bowland. David Adam went on to rewrite the software in its current form, with assistance from James Andrewartha. Many thanks to them and anyone else who lent a hand.

Snack Machine

Unlocking the Door:

The door can either be unlocked by members of Door Group through the dispense interface, or by using the keypad on the snack machine (pictured left).

The door lock is switched using the On-Hook relay of a modem (pictured above left). This provides a cheap, reliable serial interface to the door lock.

The Old Door Sensors:

In the past, the doors worked off a simple reed switch hooked up though a serial port multiplexer. The multiplexer (Blackbox - now dead) is told to changeto a certain port and a signal is sent through the port to be echoed back if and only if the reed switch is closed.

At that time, the only interface available was finger [email protected]. Much of the programming for this was done by the mad Mark Tearle.

Related Sites