I checked on the PIR and it is working correctly. To test it, I wired an LED between the module's output and gnd. The LED was going on for about 3s each time motion was detected. I trimmed this down to around 2s which should be plenty to ensure that the code detects the event.

So I'm still not quite sure why the triggering failed in the last demo but it's not a problem with timing / code.

My PIR testing is mostly done in low light so I'll have to find time in the day to check it with lots of light.

Also as Robert Wolff from 96Boards kept telling people that the project uploaded the captured images to your phone I thought I better update the code to do that before the demo during the 96Boards session early in December.