Help, I need a 5 second Logic Delay

[Travler64]

I have a logic circut, basically I have the output of an OR gate driving a reley driver but I need to delay this Logic signal 5 seconds before the relay driver.
Basically how the circuit works is I have several inputs and if any of these inputs goes High my relay driver turns on the relay and I need to delay this 5 seconds before the relay turns on and when the input goes Low again the relay will turn off and any timer I have should reset.
Any ideas??????

 

[fil]

try using a cr delay onto a schmitt trigger the input of the schmitt not only feeds the input of the schmitt but the supply of the schmitt when switching off this will cause an 'instant' low
good luck

 

[melone]

I have a fairly robust circuit, but I would like to run it through PSpice to verify full functionality. You should see something late today! Sorry for the delay. (PSpice does work at home.)

 

[Travler64]

Thanks, I will look for it....
I appretiate your help...

 

[schwarz]

I would suggest using a MONOSHOT using IC 555, the o/p of existing OR gate goes to MONOSHOT . MONOSHOT o/p is normally high and goes low on high going I/P, after 5 secs (set by RC)delay o/p goes high again.
If o/p of existing OR and MONOSHOT are fed to AND gate, the gate o/p would provide delayed HIGH signal to relay driver. If i/p goes low AND gate o/p goes low as well.

 

[schwarz]

MONOSHOT - basically one Monoshot circuit and AND gate would have to be added.

Hope earlier post was 'readable'

 

[nbucska]

How accurate must be the 5 sec?

<nbucska@pcperipherals.com>

 

[Travler64]

Does not have to be exactly 5 seconds, plus or minus 1 seconds......

 

[Travler64]

Could you sketch up something and e-mail to Travler64@yahoo.com

 

[nbucska]

From your posting (&quot;HELP&quot I understand that the purpose of the delay is to eliminate short, false alarms. In this
case I suggest an integrator with a long time constant
followed by comparator which sets a FF. The FF discharges the integrator. Reset : manual push botton ?

Do you have FAX #? <nbucska@pcperipherals.com>

 

[Travler64]

Could someone possible sketch up something and fax it to 256-726-0492
I am now desperate!!!!!!!!!

 

[melone]

I just emailed you something.