Originally Posted by
Rolfe
However, if it was put on board at Malta, how far in advance would the timer have to be set for? What sort of technology that was easily available in 1988 would allow that sort of delay to be set. So maybe, that's why the pressure sensors, so that the timer didn't start until it was within its "range" for the detonation point.
Rolfe.
By that time, single-chip digital alarm clock ICs which needed only power, a timebase, a seven-segment LED display and a few pushbutton switches to make a fully-functional alarm clock could be found in the ads in the back of Popular Electronics.
Give me one of those, a 32.768 kHz watch crystal and a 4017 to count how many times the alarm output has gone active and I could easily build a timer that could be set to go off at a particular time of day up to 10 days after setting- complete with a jack into which you could plug a display and setting switch assembly to set the detonation time (or to leave hooked up to the bomb for that "stupid action movie" look).
Simply counting off an hour or two- with +- 1 second accuracy- after a pressure sensor detects that the plane is at cruising altitude really would have been trivial even with late-80s technology.
BTW, the fuzing system for the atomic bomb dropped on Hiroshima included a timer that started when the bomb was released and prevented detonation until it had fallen for a sufficient time to be far enough away from the airplane, a barometric sensor that also prevented detonation until the bomb had fallen to a set altitude
and a radio altimeter circuit that triggered the bomb at a set height above ground level.
This was all done with vacuum tubes and relays- 1940s technology.