pulse output? pre chirps

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Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=1718
Printed Date: May 25, 2024 at 6:45 AM

Topic: pulse output? pre chirps

Posted By: 2000vsm
Subject: pulse output? pre chirps
Date Posted: July 05, 2002 at 1:37 PM

anyone know how to make pulses.. 3 pulses per second from a constant output? i'm trying to create a pre-warn chirp cuz my alarm is messed, the pre warn is like just regular siren but shorter duration which is dumb imo..

so that's what i need, please help.. i got tons of relays and caps and resistors etc...

if you can't do this, can someone help me figure out my shock sesnor then? i got this other shock sensor that has it's own pre chirp thing like there is an output right to the + siren and it does the chirps stuff itself.. but problem is i got other sensors that need this.. how can i integrate the other sensors into the shock sensor chirp? there is no wire input on the shock sensor.. so that's why.. i opened it up and it was all just caps and resistors and didoes.. no chip.. and ofcourse a quartz shock sensor unit thing.

HELP!!!!!!!!!!!

Replies:

Posted By: trusdamanr
Date Posted: July 06, 2002 at 12:32 PM

Constant to Momentary Output

The capacitor allows the coil of the relay to be energized until the capacitor stores a charge, thus de-energizing the coil. The resistor bleeds off the charge of the capacitor when positive voltage is removed from the other side of the coil. You can increase the output time by simply changing the value of the capacitor. This one will give you about a 1/2 second output.

hope this helps good luck

Posted By: 2000vsm
Date Posted: July 19, 2002 at 11:10 AM

is there any other way?

Posted By: 4Val
Date Posted: July 19, 2002 at 2:51 PM

You can use a 555-timer IC to make an oscillator which will do the trick. The problem is that the output of it will only source OR sink a max of 16mA which will not energize a standard relay. You'll need to buy a 12VDC 700 ohm coil relay.

Posted By: 2000vsm
Date Posted: July 22, 2002 at 10:33 PM

ok can you show me how to wire one of these 555 timer? where can i get these? electro sonic should have it right? please show how to wire it.. i can get a low amp relay

Posted By: 4Val
Date Posted: July 23, 2002 at 3:16 PM

Any electronics store should have them. Just search on Google for "555 timer" you'll get lots of sites showing you what you can do with this IC. You want to wire it up as an oscillator (Astable mode)

Use this site to get started:

https://www.andy-clarkson.me.uk/555/hiframes.html