.When the alarm is activated, deactivating it using the IR sensor can cause the clock to lock up and not respond to the proximity sensor until powered down and reset (either by removing the processor from the board or waiting for the backup capacitor to discharge).
The IR sensor has 3 levels of distance sensing, normally only 2 of these are used but the third was at one point intended to be used for the alarm disable. In the final code it wasn't but the link to it wasn't remmed out.
If you switch off the alarm by holding your hand above the sensor at the top or middle of its sensing range everything will work fine, however if you hold it too close to the clock it will activate the unwanted 3rd level and lock up.
If you have access to a pic programmer I've attached an updated hex file, if not please contact me to arrange a replacement processor.
Sorry about that - we really did test everything repeatedly but there's always (at least) one that gets away.
Note that this only affects the first batch of kits.
