You could use RS232 in a half duplex arrangement. Receivers and transmitters at each end all share the line. The line sits at logic ‘1’.
To prevent collisions, the house could send a ‘0’ polling pulse to the tracker once every second. If the tracker had data to send it would be sent its ‘0’...
If your LED is switched on by taking the 555 o/p high, then you can keep the LED on by taking the 'trig' pin low.
If LED on when o/p is low then take 'thresh' pin low.
How about chopping your analogue waveform at a frequency that can handle its highest frequency component.
Then AC couple the resulting sqare wave with a capacitor to your logic circuitry and DC restore to your logic return.
Have you thought of using a microcontroller? If you arrange for its internal timer to increment successive registers, you can get a clock with a resolution of better than a millisecond and five registers will give you over 24hours. It will show relative or elapsed time - not true time.
This...
You mentioned your counter was not starting at zero, which prompted my reply - I assumed you were using a decade or binary counter.
But when I look at your first posting I see you mention 74LS76. It was not readily apparent to me (because I only use 4000 series CMOS) that the chip is a J K flip...
