Our new office doesn’t have any light switches. Instead it has ceiling motion sensors. What a great idea!
- You don’t have to turn lights on and off anymore.
- Enter the room and they go on.
- Leve the room and they automatically turn off.
We are saving the planet! We are green. We are cool. We are in the IoT.
Not quite so smart!
The novelty wore off quickly, when we realised that only one sensor in a room means that we had to leave our desks every 10 mins or work in the dark. The reality isn’t as cool as the dream!
ZigBee to the rescue. ZigBee 3.0 is the control specification that 
allows smart home devices to talk together. You need a “hub” at the centre so that your phones or PCs can send control messages. You can then connect devices that turn things on and off, or sense motion, temperature, pressure, send a camera signal…. The variety is endless.
We connected a hub in our office, and then asked the office electrician to connect a light controller across the existing ceiling sensor. The electronics cost £70
Light at the end of the tunnel.
The clever bit is that instead of sensing motion we “geotagged” our phones. The GPS chip in the phone knows where it is very accurately. The hub receives the location from our phones and if we are within 100m of our office then the light controller turns on, overriding the ceiling switch. the last phone out of range turns off the lights.
We left the ceiling sensor in place so that visitors, cleaners etc can turn the lights on by entering the room.
So now we have a practical way of saving the planet, being green and think we really are cool!
