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This series of projects were triggered by two things, the discovery of the Qprox web site and the story recounted by a list member of his wife's (SWMBO) dislike of being plunged into darkness at inappropriate times because the PIR hadn't 'seen' her. There in lies the key, a PIR will detect movement, a proximity detector will detect presence - even if the object present is not moving.

The first steps in this project, which actually took place whilst I was waiting for the Qprox (QT113) chips to arrive, were to butcher an MS13E wireless PIR. The reason for this is simple, the resultant device would need to be conveniently placed, utilising a power based interface like a Powerflash module would thus require, well, power close by.

Clearly this is not always possible or desirable and the use of an MS13E is fairly useful because its PIR could be used for the initial detection and the connected proximity circuit could be used for the actual presence, all in on box as it were.

It's worth noting that this version of the project will kill the MS13E's ability to perform dusk/dawn detection and notification. This isn't a problem if you are using an intelligent controller such as Homevision or a PC running software such as Homeseer where either computed dusk/dawn times or dusk/dawn triggers from other devices can be used.

If you decide to use the notes here to recreate a proximity detector then please note that I accept no responsibility for any harm or damage done, any broken stuff or anything at all related to it.

If you build it and it works, great. If you build it and it does something nasty, bad - but it's your fault not mine.

It worked for me, it might not work for you.

If you are in any doubt then don't do it, get someone else who is confident and who knows what they are doing to do it for you.

The first thing was to take the MS13E to pieces, a simple task really.

1. Remove the small clear plastic 'thingy' that covers the screw for the battery cover, then remove the screw.

2. Remove the battery cover and batteries.

3. Turn the MS13E over and remove the 4 screws, one at each of the corners.

4. Carefully separate the front and back covers. I needed to ease the ariel wire back through the hole.

Once I'd got mine open I was horrified to see that someone (thing) appeared to have gone nuts with a glue gun, in the end I chipped away at it until I could get to the components.

The dusk/dawn sensor is located just above the small unit code push button marked (on the circuit board) as SW-PB2. Cut the legs of the sensor at the furthest point from the circuit board, that is as close to the sensor as possible.

Solder one wire to each of these legs, these are the 'trigger' wires - whatever you connect to these will be able to trigger the sending of an on/off code, this could just as easily be a door or window contact closure device. [How to connect to QT113... comming soon]

[Soon to be added]

Once the modifications are completed the unit will send an X10 Off when presence is detected and an X10 On when no presence is detected. The PIR will also function as normal.

i.e. If the PIR house code and unit code are A1 then the PIR will trigger A1 and the proximity circuit will trigger A2

The unit will trigger 'presence detected' approximately 2 seconds after initial presence.

Using a QT113-H chip would cause an X10 on when presence is detected and an X10 off when no presence is detected.

It is better to have long wires between the PIR circuit and proximity circuit than an long cable from the QT113 to your proximity 'plate'

I decided in the end I to bin the original MS13E casing and replace it with a nice looking(?) thermostat case. This basically gives more room inside so the circuit does not have to be crammed in. Any outer case should work nicely (except metal!) so you can sort something out that suits your decor.

[To do]

Pictures of MS13E converstion to switch
Picture of QPROX Circuit
Picture of both circuits together
Picture of QT113 circut diagram
Picture of completed project in 'sexy' box