Which resistor to use
Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=33428
Printed Date: August 10, 2025 at 11:59 AM
Topic: Which resistor to use
Posted By: casnj
Subject: Which resistor to use
Date Posted: June 06, 2004 at 10:16 PM
In my vehicle the lock motor wire is 5 volts DC when unlocking and 7 volts dc when locking. I want to attach a device to the lock motor wire to trigger when it senses voltage. The problem is it would sense voltage on lock and unlock. I only want the action to happen on lock. Do I need a resistor for this applicaiton? How do I figure out which one is needed? THANKS
Replies:
Posted By: auex
Date Posted: June 06, 2004 at 10:20 PM
Uh... Resistors have nothing to do with this, diodes either. What exactly are you trying to do or accomplish?
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Posted By: casnj
Date Posted: June 06, 2004 at 10:22 PM
auex]U wrote:
... Resistors have nothing to do with this, diodes either. What exactly are you trying to do or accomplish?
i dont want my device to trigger when it sees the 5 volts. I want it to trigger on anything over 5 volts say 6. Basically i want to block the 5 volts
Posted By: casnj
Date Posted: June 06, 2004 at 10:38 PM
one more thing to add.. maybe I need a relay? lock motor wire get 5 volts on unlock and 7 volts on lock unlock motor wire get 5 volts on unlock
Posted By: xetmes
Date Posted: June 07, 2004 at 7:28 AM
you could do it with a resistive voltage divider, what kind of locking system is it? ! wire? if the polarity reverses you would be better off using that fact and not the voltage level...
Posted By: casnj
Date Posted: June 07, 2004 at 7:56 AM
xetmes wrote:
you could do it with a resistive voltage divider, what kind of locking system is it? ! wire? if the polarity reverses you would be better off using that fact and not the voltage level...
heres alittle more info (+) motor lock wire +5 VDC on unlock +7 VDC on lock (-) motor wire +5 VDC on unlock nothing on lock is the resistive voltage divider still a good candidate? maybe a relay would be better. what I need to happen is if lock trigger one device if unlock trigger another. im thinking relay due to how they are used with alarms to get 2 outputs out of one. If I can just figure out what I need to use, that would be GREAT :)
Posted By: JWorm
Date Posted: June 07, 2004 at 10:46 AM
what kind of car?
Posted By: casnj
Date Posted: June 07, 2004 at 11:57 AM
JWorm] wrote:
hat kind of car?
2003 Audi a4. i have to use the motor wires for a reason!
Posted By: 9vdc
Date Posted: June 08, 2004 at 9:51 PM
hai,
about the motor,how is the funtion ?is it going forward during lock and revers at unlock.
(+) motor lock wire, is it realy gets a +vdc during unlock and lock?
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