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2 sec delay

Printed From: the12volt.com
Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=14612
Printed Date: May 09, 2024 at 10:44 PM


Topic: 2 sec delay

Posted By: Rortec
Subject: 2 sec delay
Date Posted: June 08, 2003 at 12:45 PM

Hi guys,

Ok I put this topic within general discussions and not security as the problem I need help with is a general question. (Just in case you were wondering. lol)

Ok so here goes. I currently have a timer circuit set up which activates on a 12v+ lock pulse signal. The timer has a reset function which is triggered by 12v-. Now my unlock pulse signal which I need as the reset is 12v+, so I have used a relay to change it to 12v- ok so far.

The problem is that during ‘locking’ the signals are sent down both lock and unlock wires in order to double lock. Now if connected like this the circuit will never activate as it is reset before it has begun! Lol 

I have got round this problem by using a secondary timer circuit to delay the activation of the (+) to (-) relay by 2 seconds

My question is how can or what components can I use to ignore the first pulse from the unlock wire or delay the relay activation by 1-2 seconds (apart from a timer)?

I do hope that was understandable. All help very welcome.

Rory




Replies:

Posted By: Rortec
Date Posted: June 09, 2003 at 1:51 PM

Just read my post and maybe it is a bit vague! lol

What i need is to delay a 12v+ signal by around two secs before it gets to a relay. Now i reckon there must be a simple way to do this, if you know how, that is!.

Any suggestions welcome...even if you think it will be too difficult to incorperate this.

Rory





Posted By: the12volt
Date Posted: June 09, 2003 at 1:56 PM
What alarm or keyless entry are you using and what vehicle is this in? 

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posted_image the12volt • Support the12volt.com




Posted By: Rortec
Date Posted: June 09, 2003 at 3:58 PM

This is in a 1997 Bmw M3 Evolution Euro version.The alarm is factory fit EWS 3 i think.

Im using the timer to perform total closure of all openings, which works fine. On 1997+ bmws it will total close by holding the key in the lock position, so i have used the timer to simulate that procedure

The reason i could do with the reset circuit is if you try and open the vehicle within the time i have set on the timer, it will deactive the alarm but not unlock the doors as there is a signal being sent to the locks.

The need for the 2 second delay on the relay reset circuit is this system sends a signal down both lock and unlock circuits at the same time,  which i believe double lock the doors. Now i have said earlier this will cause the timer circuit to reset as soon as you arm it, hence the need for a delay on the relay-reset.

The set up i have with two timer circuits works fine but i do feel that the 2nd timer that just delays the signal by two seconds to the reset relay seems a waste of that circuit and space, it obviously doubles the size of the unit! Also the cost.

So basically i need something that stops a 12v signal for around 2 secs

Hope this makes sense!





Posted By: xetmes
Date Posted: June 09, 2003 at 6:20 PM
ok im trying to read this and figure it out, i can give you a circuit that will inhibit the relay from closing for any length of time up to 30 seconds, is that all you want? If so let me know.




Posted By: xetmes
Date Posted: June 09, 2003 at 8:03 PM

sorry i posted in the wrong thread





Posted By: Rortec
Date Posted: June 10, 2003 at 1:17 PM
lol, i want the complete opposite, to inhibit the relay from opening for 2 secs. There must be a way




Posted By: MielGibson
Date Posted: June 12, 2003 at 9:55 AM
Try this, it might work.
You might have to change the capacitor to get a longer delay. Don't change the resistor to a higher value, it will limit too much the current to the relay.

How it works:
When power is applied, the capacitor "acts" like a short to ground, bypassing the relay.
The resistor limits the current so the capacitor won't charge 'til approx. 2 seconds after.
The input pulse should be longer than the output delay.

posted_image





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