IN<250ms = 50msOUT // IN>250ms = 50msOUT + T + 50msOUT

[misiacik7]

Hi there.

Input impuls is from microswitch 12V source
Output implus should be around 50ms or more.

In case of the input impulse will be shorter than 250ms - output impuls 50ms should be once right after pressing the microswitch.
In case of the input impulse will be longer than 250ms - first output impuls 50ms should apear right after pressing the microswitch and second output impuls should apear right after releasing the microswitch.

(best should be if the threshold can be adjustable - range 150ms till 350ms)
(best should be if the length of output impulst can be adjustable - range 50ms till 200ms)

Hope all can be done without need of uC

Thanks in advice

**broken link removed**

 

[alec_t]

Something like this?
U1 is a CD4093 quad Schmitt NAND IC.
Pulse voltage source V2 simulates the switch.
When first pressed, an output pulse from gate U1d is generated, of duration P1 determined by time constant C1 x R2.
After a switch closure period T set by time constant R3 x C2 a second pulse is generated by U1D, of duration P2 determined by C3 x R4.
The times P1, T and P2 can be easily adjusted by varying R2, R3 and R4 respectively.

Edit: I've just realised you wanted the second pulse to start on release of the switch. I'll have a re-think ....
And can you clarify whether the switch provides a +12V level when pressed or when released?

 

[misiacik7]

Thanks for response

It is an ordinary switch, so when pressed it gives +12V pulse till being released.

And when it is pressed for longer than 250ms i want to make it another short output impulse.
(otherwise it will give only one pulse at start, at being pressed)

When pressed input voltage is +12V and when released 0V.

 

[alec_t]

Ok. So here's a revised circuit.
Ignore D1 and V2 (which are used just for the simulation).
Note that the switch now supplies 12V to the 'In' point (left of circuit) when closed. The logic circuits also need a permanent 12V supply (not shown).
U1 forms a first monostable pulse generator giving a 50mS pulse P1 when the switch first closes.
U2 forms a second monostable pulse generator giving a 50mS pulse P2 when the switch is released, provided the switch has been closed for a timed period T = 250mS.
As before, the P1, P2 and T periods are adjustable (by varying R3, R4 and R2).
There are now two outputs; a positive-going pulse pair from gate U1d (as shown in the attached screenprint) and the inverse from gate U2d.