push button start with rfid alarm

Hello,

I am trying to do a variation on the pushbutton start that has been discussed at length here. My goals may be a little different:

I am installing this in a 2001 Miata. I have a simple RFID alarm that will be installed. When the driver approaches the car, the alarm will unlock the doors and 'enable' the button and relay array. I want to have one button (Honda S2000) that when pressed a single time, will turn on the accessories. If it is pressed and held for a period of time (1.5 seconds perhaps?), the ignition will turn on and the starter will engage. When the button is released, the starter will disengage and the engine will remain on. When the button is pressed again (while the engine is running), the ignition and accessory will turn off.

the12volt posted this in March 2003 (and probably several times since). It describes a 12v+ output that will stay on with a momentary negative output. The same negative output will turn off the 12v+ output. In my quest, the negative output could be from my start button.
https://www.the12volt.com/images/latch1-2Off.gif

I am struggling to find a way to incorporate a timer relay that would give my 1.5 second delay for the starter relay. I am also hoping that in the event the RFID Fob gets out of range of the car (i.e. carjacking or simply walking away), the car will shut off and the doors will lock.

I plan to disable the mechanical wheel lock. I appreciate there are many different opinions on this and I am not trying to start, fuel or participate in a debate. I also have a 555u to deal with the chip in my model's key. One wrinkle I would like to work out is that I would like to be able to start the car with a key also in the event complicated relay array malfunctions. Obviously, this would be with a key that is not in the 555u and it would still be necessary to have the fob from the RFID alarm present. In other words, an ancillary goal is for the whole ignition area to look and act normally (as long as the alarm was happy).

I found a product that will do what I am describing made by Flaming River and it looks nice but the $500+ pricetag is too steep - not to mention that I am hoping to learn a little through this homemade system. If this works, I would like to put the same system in all of my cars and code all of the alarms to the same set of fobs thereby allowing me to drive any car I walk up to without digging any keys out of my pocket. That would be pretty cool! :D.

Thank you for any suggestions or links you might be able to provide!
-hyde (your newest member!)
P.S. could someone please make that gif appear in my post? Thanks!

First, here is the picture you linked to:

My perspective of this is that it is a terrible idea to try to build an entire sophisticated control system using only relays and timing relays.  I'm not saying it can't be done, but you'll going to need a trunk full of relays to do all the things you are trying to do, and the system still probably won't do all you want to do.

First, we'll start with the RFID alarm.  You want to use the "unlock" output to enable your push button system.  How would the system know to disable it if the driver walks away instead of starting the car?  It doesn't sound like your alarm has a "keyfob in range" output to work off of - that could be a serious security flaw (which isn't a big deal in one off custom alarms). 

If you want the the same button to perform both start and stop functions I would highly recomend you build in tach monitoring - ESPECIALLY if you want to retain the key slot.  The last think you want is to try and keep track of if the system "thinks" the car is running or not.

Instead of looking for timing relays and relay controlled toggle switches that use 5 relays you should be researching digital circuits.  They are smaller and will provide more features - even if you have to build a modular system using several different commercially available timing / frequency modules.

I guess what I'm trying to say is that the system you "want" is a bit much to expect from simple relay logic.  Have you read my thread on developing a push button start system on here?

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Kevin Pierson

Kevin,
Thank you for your thoughts. I will search for your thread tonight and see what I can learn from it. Thanks!
-h

LOL! I read that thread during my searches! :). Unless you are selling completed units, the control logic is above my comfort level to put together.

I'm hoping the relay logic will work like this: Using the relay array you linked for me above and the RFID remote, I think I can make this work. One button can turn on and off the accessories (with those relays). Pushing (the initial 'accessory on' push) and holding the button for a predetermined amount of time will turn on the ignition and engage the starter. The starter will run until the button is released. If the button is pressed again (momentary), the ignition and accessories will turn off.

While the engine is running it would be possible to engage the starter (grind) if you pushed and held the button but a quick push would turn everything off. The only drawback I can see would be if you killed the engine at a stoplight. At that point, you would need to push the button once to 'turn off' the system before pushing and holding to turn everything back on and engage the starter. It could also be annoying if your engine was having trouble starting and you needed to crank/stop/crank several times. In this scenario, you would also need to make a momentary push between held pushes to reset the get the system back to square one.

The whole RFID part of the system seems to be the simplest. If the fob is in range, things work and if it isn't, they don't. This should be able to be accomplished through the door locks, the starter interrupt of any other status logic the alarm is putting out. I like Kevin's idea about the tach status, but I don't mind holding the button until the engine starts and it is necessary in fact with my design concept.

On a side note, having to turn the key in the ignition defeats the whole purpose (to me). I'm looking for function AND 'cool factor'. Nothing against peeps who just want a button to look cool - I just want mine to do a bit more ;).

-hyde

Any thoughts on the delay incorporated in the above diagram?

mr_hyde wrote:

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Any thoughts on the delay incorporated in the above diagram?

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I did something similar except I used biometrics instead of rfid.

You might want to try and use a remote starter as your main brain and work from there.

that would cover your acc only and your start functions

use the starter kill output for whatever you need to

and depending on your unit, you will have several other timed or programable outputs to work with. It would greatly simplify what you are trying to do


and in case anyone wants to inquire about the biometrics project I am sorry but it was tested and work 100% except when the temp dropped below 50 degrees. All weather finger print readers were too expensive for me to leave the set up on the car.

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I'm working close to that idea - but I'm using the rfid remote/alarm as my main brain. I would be done already if I simply wanted a pair of toggle switches to run the accessory and the ignition with the button to key the starter. The rub is I'm trying to make one momentary button do the whole thing (when authorized by the alarm). If I get some more bench time, I'll keep tinkering but time is short this time of year... :(
-hyde
P.S. Thanks for the thoughts! :D

mr_jimbo,
Do you have a sketch of your wiring scheme? I'm close and I'll start whacking and hacking when I know for sure :p.
-h

Get anywhere on this? I just started the same project lol.

Yep. Gave up and ordered a digital guard dawg. I wish I had the time to make this work but their product does everything I want solid state with support. I'll keep an eye out here though - I have more cars ;).
-h

Update - Digital Guard Dawg installed and works perfectly. I have 'lost' the accessories but I'm planning to put in a simple toggle to run the radio at a later time. Thanks :)
-hyde