a wire indicating the car is running?
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=97392
Printed Date: May 07, 2024 at 3:57 PM
Topic: a wire indicating the car is running?
Posted By: fbird08
Subject: a wire indicating the car is running?
Date Posted: September 24, 2007 at 1:58 PM
I know this is a bit out there but do any of you know of a wire that goes to ground or 12V once the engine is started and running? Theres has to be some sensor telling the car that the engine is spinning. I'm working on a push button start project for my 93 sentra (practice vehicle before it goes in the FX). Let me know if you guys have any ideas on what type of sensor/output I could use. Thanks ------------- Money is just paper
Power is fleeting
But your word is everything,
If your word means nothing,
You are nothing...think about it
Replies:
Posted By: tedmond
Date Posted: September 24, 2007 at 2:48 PM
hey, the wire that indicates the engine is running is know as the TACHOMETER (tach) wire. Go to the vehicle wiring diagrams and look for you car. I will show you the colour, and location of wire.
Posted By: fbird08
Date Posted: September 24, 2007 at 3:01 PM
A tachometer (tach) wire puts out an AC signal. If you hooked that up to a relay to trigger anything the relay would just turn on and off at an incredibly fast rate. (Yes you could solve this with a diode and capacitor) That being said, I need an output that goes to ground or 12v when the engine is running. I think I mentioned that in the first post but your a newbie....I'll let it slide this time, haha.
-------------
Money is just paper
Power is fleeting
But your word is everything,
If your word means nothing,
You are nothing...think about it
Posted By: tedmond
Date Posted: September 24, 2007 at 3:08 PM
lol sorry, though you were asking for a tach wire for an alarm cuz this is an alarm forum. but i did see a schematic for a start push button. if i can find it ill repost it asap sorry thanks
Posted By: fbird08
Date Posted: September 24, 2007 at 3:12 PM
No worries. I already checked out all those push putton diagrams. Unfortuantely, the only thing I could find was the charge light on some BMW's. My sentra does not have that. I might just have to do the diode and capacitor (maybe an op-amp for a buffer) off the tach. I would prefer not to though. Seems like reinventing the wheel if the wire already exists somewhere.
-------------
Money is just paper
Power is fleeting
But your word is everything,
If your word means nothing,
You are nothing...think about it
Posted By: tedmond
Date Posted: September 24, 2007 at 3:19 PM
hey, i dunno if this is useful or not but here you go https://www.honda-tech.com/zerothread?id=1721308
Posted By: tedmond
Date Posted: September 24, 2007 at 3:21 PM
maybe this can be useful? https://www.crxchaos.co.uk/starter-button.html are you trying to make the push button not allow cranking once the engine as started?
Posted By: fbird08
Date Posted: September 24, 2007 at 3:30 PM
That is definately another approach. I'm using an rfid card in my wallet with a sensor in my seat to keep the security end of it. (I am doing away with the key) Yes, I am trying to make the push button not crank while the engine is already running along with a few other functions. ------------- Money is just paper
Power is fleeting
But your word is everything,
If your word means nothing,
You are nothing...think about it
Posted By: tedmond
Date Posted: September 24, 2007 at 3:44 PM
well i have tried this start button as well, got it to work for my friends car, never got it to work by using the kill start function when the engine runs. A cool thing i wanna try is, when the installer for my house alarm came, he wired the magnetic triggers for doors and windows. He gave me a bag full and said ah i dont need this lol. well i wanted to put one of those sensors into the car for a push start. when the magnet is in contact or close to the receiver, it will allow the circuit to complete. I havent tried, but if i do ill for sure see if i can assist you. I am a noobie in the forum, but i have been doing audio and car electronics for 5 years. Want to get a MECP, but no time for that. Im a busy student in highschool so yea. good luck
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