Need X10 Security Pinger- poor mans RFID

["Bob Sisson" <bob@xxxxxxxxxxxxxxxxxxxx>]

I basically want to take an X10 MS10a or a DS10a security device and modify
it to transmit a "here I am" signal about every 30 seconds.

I thought about using an Eagle-eye and using the on/off buttons, but those
could be mimicked too easily.  With the Security devices the random number
code will keep the false to a minimum.  (actually someone else's idea)

I figure a door switch (DS10a) with a monstable feeding a mini relay would
be pretty simple....

Any one got a schematic for either the DS10a or the MS10a?

What am I going to use it for....

I am going to put it in my car and the non-stable will be driven by the dash
light circuit.

Signal... the garage door should be open...
I am either in my garage getting ready to leave, or coming in...

No Signal... the garage door should be shut....
Either the car is in the garage and turned off, or I am out of range....

As I also have a directional driveway sensor, I can double check when it
goes off to see if  the "pinger" is in range and the state of the doors...

Any one got either a schematic or a better idea ?


Bob