Re-Triggering a 555IC without the output going low
Re-Triggering a 555IC without the output going low
(OP)
Hi All,
Wish I had a pen and paper, this one's easier drawn
I have a situation where I have a 'flickering' alarm closure which I need to effectively regulate into a solid closure.
I guess what I'm looking for is a monostable circuit with some way of re-triggering the time delay without sending the output LOW at any stage.
I can't let the 'flickering' alarm simply re-trigger the 555 on it's own unfortunately because that would set my auto-dialer (which sits on the end of this thing) would dial up my 5 pagers again
Any suggestions or pointers would be MUCH appreciated.
Thank you all in advance.
Tim.
Wish I had a pen and paper, this one's easier drawn
I have a situation where I have a 'flickering' alarm closure which I need to effectively regulate into a solid closure.
I guess what I'm looking for is a monostable circuit with some way of re-triggering the time delay without sending the output LOW at any stage.
I can't let the 'flickering' alarm simply re-trigger the 555 on it's own unfortunately because that would set my auto-dialer (which sits on the end of this thing) would dial up my 5 pagers again
Any suggestions or pointers would be MUCH appreciated.
Thank you all in advance.
Tim.





RE: Re-Triggering a 555IC without the output going low
RE: Re-Triggering a 555IC without the output going low
Second, why doesn't the LM555 timer work? Take a look at the application notes on the LM555 timer, www.national.com, and look at the monostable. I believe that the monostable will not retrigger on transitions during the "unstable" portion of the waveform. Otherwise, you will have to set-up either a latch circuit (R-S latch) or a simple D-Flip Flop using the output of the 555 as the clock signal.
Just a few thoughts. Keep us posted and good luck!!!
RE: Re-Triggering a 555IC without the output going low
http://www.e-insite.net/ednmag/index.asp?layout=article&articleId=CA196470
The task you decribe is usually called debouncing and you will find lots of other tips if you search for the term "debounce".
RE: Re-Triggering a 555IC without the output going low
The TI app notes show this application...