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i must have the code for detecting a missin g pulse? do some one have some for me to see?
HELLO @@@ HOGAR HERE.
If I understood your problem correctly , you can use a re-trigger able mono-shot with 2 to 4 Sec delay. Re-trigger this mono shot by the pulses in your problem.
If this trigger pulses misses the mono-shot will no longer will get trigger and it will change the state.
This state of the mono-shot can be used to trigger your alarm circuit. Hope I am clear.
Regards
hohar itp
[rememba, i am unique, just like you and you and you]
i am unique
Oh, yeah.
The required delay must be chosen according to the expected repetition rate of the G pulses - how do you know that 2-4s is anywhere near the requirement?
I agree with hogar,
Brillient solution.
Simply use a "Dual retriggerable monostable multivibrator" type 74hc123 to sense two pulse (use two same ICs for 4 pulses and so on ... )
Study the datasheet here: www.nxp.com/.../74HC_HCT123_4.pdf
I think it's possible to realize the circuit without any processor... it's a really "older" solution.
Good luck
zuisti
(chef programmer)
Kind moderators!
I see more letters, which I did not write, on this forum. Somebody abuse my name, and my other letters written onto an other forum are copied here, modified many times. I ask it - if possible - let it be deleted, and I call upon the perpetrators in order for it to be stopped though!!
The real zuisti, an old (65) engineer from...(you know it I think). And ... I'm NOT a chef programmer !!
chef programmer
You know, a modern microwave owen can be quite hard to program. Some chefs may need a specially appointed programmer to handle the more complicated cuisines.
you can use a re-trigger able mono-shot .... I agree with hogar, Brillient solution.
My name for a monostable is "One shot in the foot"
monostables are so awfully noise prone that they are more likely to cause problems than solve them.
Of course you can use a 4 or 6 layer board with a schmitt located within millimeters of the OneShot 'isolating' the trigger and 12 decouplig caps surrounding the OneShot and maybe get lucky.
Erik
PS for our foreign friends, an American expression for making problems for yourself is "shooting yourself in the foot"
"monostables are so awfully noise prone"
They're just trying to make up for all the other pulses that he's lost...
In a high-end digital scope, you have to use very special designs to catch ps glitches.
But as soon as the pulses gets within "computable" range, I do recommend using a pin interrupt, port interrupt or a timer or similar to handle the detect of the pulse, or timeouts waiting for pulses. It consumes a single pin on the processor - and an external circuit will also require some transfer capability of the processor. But the advantage of being able to change the timeout value or possibly switch between positive or negative flank, ... by just updating a software parameter can be invaluable.
And a later software may be updated to look at the variance between the pulses, allowing detection of vibrations in a mechanical system or slow acceleration in an electrical motor or similar. Real hardware is nice to have when the processor lacks the capability of handling a problem. In most other situations, software is recommendable. A late software update may be the difference between winning or loosing an important deal - either by being able to match a competior, or to differentiate from them.