keep relay open for a amount of time
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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=101076
Printed Date: May 09, 2024 at 6:20 PM
Topic: keep relay open for a amount of time
Posted By: zeecue
Subject: keep relay open for a amount of time
Date Posted: January 12, 2008 at 8:08 AM
Hi I have a trunk release option( negative triggering) on my alarm, but how do i wire this to a relay, so that the relay is opened for like 15 seconds. I would like if the amount of time could be adjusted by fx a variable transistor, and is it possible to make it turn of the relay, when i turn the key to ignition? Best Regerds Morten
Replies:
Posted By: tedmond
Date Posted: January 12, 2008 at 8:26 AM
what car and what type of alarm do you have? some alarms have adjustable timed circuit on aux. If that doesn work, or the option is not available, youwill end up using capacitors to hold the charge long enough for it to open.
Posted By: zeecue
Date Posted: January 12, 2008 at 8:54 AM
Its a Inca Pro, with VW flip key, look alikes. I think Giordon makes the electronics, in the alarm, as the schematics are the same as for a Giordon alarm. See the schematics here: https://zeecue.dk/alarm.php What kind of sensors and triggers can i mount to the alarm? Best regards Morten
Posted By: tedmond
Date Posted: January 12, 2008 at 11:28 AM
its hard to read my friend. but as for trunk, im sure giordon only has postive trunk outputs. if so do you know if your trunk is a negative or postive trigger? what car is it?
Posted By: zeecue
Date Posted: January 12, 2008 at 11:53 AM
Its a Skoda Felicia Pickup Fun( The same as a Vw Caddy Pickup(Polo), just with 4 seats. https://zeecue.dk/ParkingHeater.php - Here are some pictures. It says in the manual, that the release is negative, triggering, look here https://zeecue.dk/alarm/Trunk.jpg I want to use the relay, so i can turn my fog lights on, when i push the open trunk button on the remote, and then automaticly turn them off after like 15-30 seconds.
Posted By: tedmond
Date Posted: January 12, 2008 at 8:47 PM
your trunk release is postive wire up a relay like so. 85 - constant 12v
86 - negative trunk trigger from alarm
87 - high current 12v fused @ 10 amps
87a - to trunk wire (switch side)
30 - to trunk wire motor(solenoid) side also to do the fog lights 85 - constant 12v
86 - negative trunk trigger from alarm
87 - High current 12v
30 - to fog light wire
using some capcitors on the coils 85 and 86 will hold enough charge for 20 seconds.
also the negative trunk wires goin to the relay, diode isolate them with the cathode (white band) towards alarm. a 1amp diode 1N4004 will do.
Posted By: zeecue
Date Posted: January 13, 2008 at 7:16 AM
Thanks, usefull information.
Posted By: bugman72
Date Posted: January 18, 2008 at 12:49 PM
I have a need for a delayed-off timed relay similar to what zeecue was needing. My application is slightly different, although the voltage is the same. Hopefully someone can tell me if this is what I need.
As some of you may know, the Xbox 360 has a slight (read: BIG) overheating issue. I have made some modifications to my unit in order to increasing its cooling ability. One of these mods is wiring the exhaust fans to a constant 12V as opposed to the variable speed 5V normally. I have also added an 80mm intake fan on the side. Now, with that explained, here is what I am wanting to accomplish.
What I would like is to have a timed circuit that upon the console being turned off, both the intake and exhaust fans remain on for a specified period of time (I would like about 10 minutes). At the expiration of said time, the fans would automatically shut off. As it is right now, the 12V constant source that I have turns off as soon as the console shuts down, so I assume that I could use that as my trigger source. Right now the 80mm fan has its own external 12V power source. I was thinking about wiring the rear exhaust fans to the same power source.
Will using a relay (I assume you are using a 30A Bosch, correct) wired similarly to what tedmond suggested work in my application? I'm not exactly sure what I would need to do in order to accomplish this. I assume that the 12V from my external power supply would go to 85, correct? From there, I'm not exactly sure what would need to go where.
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Greg
Posted By: chriswallace187
Date Posted: January 19, 2008 at 4:22 AM
Greg, Unfortunately it wouldn't be feasible to have the relay activated by capacitors for that long of a time period. 20 seconds is doable; 10 minutes would probably drain a 1 farad capacitor just operating a relay, without any kind of external source.
You may be able to find a pulse timer that would supply an output for that long. If not than I would suggest building an IC setup, or possibly mounting a thermistor near the processor (this wouldn't work a time delay but it would reduce fan speed as the processor cooled down). Unfortunately that's not really simple either. ------------- C Renner's Auto Electronix
My service is cheap, quick, and good - pick any two
Posted By: bugman72
Date Posted: January 19, 2008 at 2:57 PM
I had an idea that doing a time delay for that long via a capacitor might be a bit of a stretch. I have found a product that seems to be the answer. I may end up buying this, although half the fun is building something from scratch and seeing it work.
Here's the product. There are a number of possible setup schemes with this unit. It can be triggered by either a (+) or a (-) trigger. You can set it to where the relay turns on at trigger and then stays on for the delay time (1 sec to 60 min) or turns off when triggered and then back on for the delay time. You can also set it to where the delay time starts when the trigger is first applied or after it has been removed. You can also do either a 1-shot or a repeat for a specified interval. Quite a bit of stuff all in one package. It will work in either a 12V or 24V environment.
------------- Greg
Posted By: chriswallace187
Date Posted: January 20, 2008 at 2:28 AM
That actually looks like the perfect answer...under $20 at some places too. If your circuit design skills are pretty good you could probably do a purpose built setup for your project but it'd surely take up more than $20 worth of your time.
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C Renner's Auto Electronix
My service is cheap, quick, and good - pick any two
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