Scenario

 We have a customer, lets call him 'Alex' who has a combination of LED and conventional lighting in his home.  He has got switch plates with ultra-sensitive PIRs and buttons for 'Off' and 'Next' scene.

  Request "When I come into a room, if the lights are off, I want the LED lighting to come on".

  As with all customer requests, it seems simple at first, but actually the requirements look like:

1. The Switch Plate should operate as expected at ALL times
2. The LED lighting should only come on when it is DARK AND the WebBrick is at Scene 0
3. The PIR should not operate if other lights are on
4. The PIR should give an 'Exit' delay when the lights are switched off (otherwise the LED lighting comes on again immediately with the next movement)
5. The solution should fail safe if the network is down
   

Assumptions

• The LED lights are configured on Scene 1
• The PIRs are hypersensitive 10m range 5V supply with 'float' and '5V' as idle and detected outputs
• There is a TTL digital out used as PIRDisable, with a 4.1K resistor to the output of the PIR (i.e when held high the PIR will not operate).

 Configuration

1.  PIR output connected to digital in configured to ON Scene 1 on a rising edge (options=1)
2. Scene 1 through Scene Max set the PIRDisable output high (therefore (1) above) cannot be retriggered
3. Scene 0 is set to Ignore PIRDisable, therefore the PIR remains disabled when the lights are switched off
4. The Gateway(HGA) detects the transition to Scene 0 (using the state of the 'Off' mimic)
5. If isDark is true, then a delayed event is set to set the PIRDisable low in 'n' seconds (say 30), thus re-enabling the PIR
   
6. If isDark is false then set PIRDisable high (its light so don't trigger)
7. On transition from light->dark set PIRDisable(s) low
8. On transition from dark->light set PIRDisable(s) high

 For those of you with cunning minds (Mr Willet you know who you are!) I leave it to you to reply to this post with:

• Improvements
• The solution to switch off the lights under no movement in 'n' minutes 

Happy WebBrick Building

Andy 

Hi Andy I forgot to mention there are probably going to be two of thease pir's in each room hense two light switches

this might cause confusion or make it simpler that the lights do not need to be turned off accept for bed time. as the activity in the room should be enough to trigger one of the pir's all of the time I have been running this in its simplicity at the moment with only one PIR and it seems to be working O.K.? but as I am sure you will come up with a technicality wich makes this a brain rattler