Remote Start for Vehicle Alarm and a Kill Switch for Fuel Pump - Page 1
Forum section: electronics / projects

author: Falcon69
author_rank: Super Contributor
timestamp: January 17, 2017, 03:47:47 am
content: So, Here's the deal, and a project I'm going to start work on.I have an after market alarm system which includes a remote car system. I also want to put in a Hall Effect Sensor that will only allow the vehicle to start the truck when triggered, i.e. when magnet gets close. That I can see being the easy part. I just tap into the On position (the part you turn the key on to kick the starter on), of the ignition with the sensor and a relay.But, How would I make it work so that when the alarm is triggered from inside to remote start it on the cold days? Maybe use an arduino to bypass the hall effect sensor/relay when it receives a signal from the alarm for remote start?But, then again, putting in a kill switch for the starter/fuel pump could defeat the purpose if it is also dependent on the alarm, as a code grabber could possible duplicate the signal, and allow the car to start anyway.Does this make sense what I'm trying to do?Basically, I like the features of the alarm, remote start, tilt sensor, alarm siren, pager system (in reality all really useless to a professional thief), but, also have the feature of an independent system in place that will only be triggered or allow power to the fuel pump when a magnet gets close. The sensor could be hidden ANYWHERE and all you do is just wave the magnet over it till it triggers, start the vehicle, then remove said magnet once engine turns over. Once it turns over, it will latch the relay and have the connection until vehicle key is turned off again, allowing the fuel pump (or power to ECU, or whatever) to operate as normal during driving.But, I'm still confused on how this would/could work with the remote part of the system, so I could start the vehicle from inside the house on these VERY cold days. I'd really like to eliminate the arduino if I can, just do it with a few relays and the sensor and magnet, and of course passives and relays.Any ideas?Thanks in advance.

author: Falcon69
author_rank: Super Contributor
timestamp: January 17, 2017, 04:23:55 am
content: Hmm, I found this. Not sure what the PGM-FI Main Relay is though, the post on this site didn't explain it.QuoteIn this post, they are referring to the Viper 5900 alarm, but I couldn't find any reference so far to it regarding the PGM-FI Main Relay. If I knew what that is, then it should be easy to figure it out for the alarm I'll actually be purchasing (undecided yet). Most, if not all, alarms are very similar in how they all wire up, so shouldn't be a problem if I can figure this one out, then all there is to do is make the switch and hide it somewhere. I thought about a pressure switch...but I like the fact that this hall switch I could hide somewhere deep behind the dash, and just waive a magnet close by.

author: Falcon69
author_rank: Super Contributor
timestamp: January 17, 2017, 04:37:09 am
content: I wonder if PGM-FI stands for "Programmable Function One" output of the alarm, which could be what the remote start of this particular alarm is connected to. Most alarms all have programmable outputs, for remote starts (for those without it on-board) or for things like glass breakage sensors or tilt sensors, etc. So This could be what they are referring to.http://www.directeddealers.com/manuals/ig/viper/N5301V_05-06post.pdf

author: Falcon69
author_rank: Super Contributor
timestamp: January 17, 2017, 04:48:43 am
content: Okay, think I figured it out.The car they are working on in that post, was a Honda.The relay, PGM-FI appears to be the factory relay used to turn the fuel pump on and off, so that is what they are referring to. Easy enough. I would need to find the really of the vehicle I am working on and set this up.Souonds like this might work, now to design a circuit that will latch (or close the circuit) once the magnet triggers the Hall sensor, then go back to Open after the engine (key) is turned off. I guess the easy thing would be to leave the magnet in place, but That is easier said then done, and if magnet moves just a short distance away, it could shut the fuel pump off while driving, not a good idea.Any suggestions on a good reliable simple circuit that could do this? I already know how to do the hall-effect/magnet set-up, but to keep the circuit closed once magnet triggers, I'm unsure yet, but I'm sure with some more research I'll figure it out. A push in the right direction or key words to search for could help me.

author: Falcon69
author_rank: Super Contributor
timestamp: January 17, 2017, 05:40:44 am
content: Okay, I drew up a small diagram. I think this is correct, seeing how Hall sensors Sink to ground when triggered, this should activate that relay and connect 30 and 87 together, thus activating the fuel pump, or turning it off, if the alarm is set When remote start is activate, it should activate the other relay, connecting once again, the fuel pump to allow engine to run.Does this look right to any of you? Did I miss something?

author: Falcon69
author_rank: Super Contributor
timestamp: January 17, 2017, 05:45:18 am
content: hmm, second relay, I may need to put the 12 volts to pin 86? and switch the other to 85? Pin 85 is Coil Ground, and 86 is Coil Control. It's been awhile since I installed car alarms and stereos, I can't remember if it even really matters.