# HOW TO: add RFID to operate like an OEM to our cars



## Whiterabbit (May 26, 2006)

I've been thinking about ways we can do this securely. Some of the methods used by more "hip" cars bugged me. I never quite liked how they accomplished what they did.

Sat in a CX-9 the other day. The RFID card will not unlock the doors. This must be done ala remote. Once inside, the RFID enables push start, but even that isnt progressive. the car has a traditional keylock ignition, there is just a twistknob in place rather than a key. Starting the car is identical to a keyed car, just no key.

How easy it is to simulate this in our own cars!

We start with our keyless entry, ensuring there is an ignition lock tied to the arm/disarm command. Unlocking the car will enable ignition.

Next, we add the ignition switch. We start with a valet key. This is retrofitted inside a knob that will cover the ignition keyswitch. The purpose is no more than to make it not look like a key left in the ignition. Keysense may need by-passing, I havent thought those consequences through yet.

Finally, we enable the remote bypass with a transponder bypass from DEI for remote starts. This is buried into the underdash, tied to an RFID receiver. That is to say, when the RFID senses a keycard, keyfob, any RFID device that has been programmed, it bypasses the transponder.

Thus:

The alarm interlocks out the ignition.
The RFID interlocks the transponder.
The key-knob interlocks watchful target-of-opportunity thieves.

Starting the car is as follows:

User remotely unlocks the car. doing this from a distance is OK because the car is transponder interlocked. User is free to place their keys back in a pocket on the way to the car at this point. User gets into the car. vehicle entry is sufficient to enable the ignition. User then starts the car and drives away. At this point user could lock the car or remove the RFID without affecting the car's state. If done, the car would be interlocked out once ACC is cut. If not, ACC can be cut and ignition reapplied at will.

For car demos, hitting unlock is sufficient to enable a friend to enter the car and start the stereo. Will not allow them to start the car. Or anyone else, till you are sitting in the car with them.

I've found RFID on EBAY for $13 shipped but have a usable range of 6 inches. No good. My goal is to find an inexpensive RFID sensor with a minimum useful range of 18 inches, maximum of several feet. Passive only for the purposes of keeping the ID key as small as possible.
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Who's got some other commentary, ideas, applications etc for RFID?


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## Whiterabbit (May 26, 2006)

how about another application for RFID. This will work with the $13 three inch RFID:

tie it to your remote start. Once in the car, place your keys or cellphone or wallet (whatever you link to rfid) in a designated spot in the car.

Lets say you have a dime RFID chip glued to the back of your IPOD and you set the IPOD in an exposed cradle. Behind the cradle is the RFID sensor.

The act of placing the ipod in the cradle activates the remote start. Then drive off.


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## Whiterabbit (May 26, 2006)

How abut tying it to your stereo ACC input (in parallel with the vehicle ACC, of course)

When someone wants to go off and demo your car, give them the keycard for them to place on your dash. Or cupholder. or somewhere else. Activates ACC to enable the radio. They can demo to their heart's delight.


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## Whiterabbit (May 26, 2006)

you can actually use an active RFID to automatically unlock your doors as you approach. Makes me nervous as hell to do something like that.

But you could DO it.

You could also do this with your 3" range passive RFID installed inside the doors next to the car door latch. then you buzz yourself into your car just like you would if you worked in a locked secured office building.
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oh man, now that I think about it, if I can find a passive RFID that I can laminate to the inside of my wedding ring, I could get away with placing a 3" range RFID sensor behind my drivers side door latch!

or trunk and tie to the trunk release.

hell, at $13 a pop, every door gets an RFID!


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## Whiterabbit (May 26, 2006)

and speaking about pops, would it be over the top to wave a card or your phone or wallet over the car or near the car and have the door pop open at you?


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## dogstar (Jan 31, 2007)

heh, we have maglock doors at work, and I think our cards are passive RFIDs. 
If I'm understanding what you mean, with the $13 sensor I could use my maglock card to open my car door and/or start the car.

Hmm, very cool and definitely show car worthy, but I would want an alternate access system incase the battery craps or other problems arise, like when the maglock card gets forgotten at home.


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## Whiterabbit (May 26, 2006)

thats what your regular key is for. We install remote starters in our cars. doesn't mean we dump the ignition switch.

Some of us have door pops. Doesn't mean we pulled the latches. (sometimes pulling the door latches looks....terrible! )

The $13 RFID readers are 125k readers. if your maglock card is 125k? would totally work! Just requires programming


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## dogstar (Jan 31, 2007)

Whiterabbit said:


> thats what your regular key is for. We install remote starters in our cars. doesn't mean we dump the ignition switch.
> 
> Some of us have door pops. Doesn't mean we pulled the latches. (sometimes pulling the door latches looks....terrible! )
> 
> The $13 RFID readers are 125k readers. if your maglock card is 125k? would totally work! Just requires programming


Good point... just didn't want to end up disabling anything, would have to take a pretty serious look at how my car is set up, but I do know that it doesn't have chipped keys.


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## Whiterabbit (May 26, 2006)

That's tougher. without the RFID tied to something like a transponder bypass, I'd consider more secure alternatives.

For example, rfid tied to the ACC, with a pushbutton ignition added on top. That allows keyed starts as a bypass. That allows you to set your keycard on the dash or a more secure location like a cupholder of change pocket. something that wont fall out during driving, right? Then can pushbutton start the car. The nice buttons are available from dealerships as spares. such as the honda s2000 or many hybrids.


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## chad (Jun 30, 2005)

Well, while in the design phase, why not a short range RFID to get it up and running. For example under a cubby where you would put your keys?, drop the keys in the spot and the car goes?

I may get a useful s2000 starter button yet


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## Whiterabbit (May 26, 2006)

chad said:


> Well, while in the design phase, why not a short range RFID to get it up and running. For example under a cubby where you would put your keys?, drop the keys in the spot and the car goes?
> 
> I may get a useful s2000 starter button yet


I dont like the s2000 starter button. It's just like ignition. you have to hold it down till the engine turns over. That is 50% engineerig! I had a better idea.

Tie the pushbutton start to the remote start. That way, a simple tap will start the car all the way to an idle. But my remote start isnt well designed either. There is a 4 second lead time before the car tuns over. Even the OEM GM remote start has an immediate turnover!

Though there is an electronic input for activating remote start on my keyless, it still activates the 4 second delay! unacceptable. I am very dissapointed. (though I dont mind the 4 second delay during remote activation.)

no way to win, I swear!

I definitely thought about the key cubby. I believe that is how volvo implements their RFID. And my generation civic would be real easy to add the antenna under the change pocket.

but if I am gonna carry the keys by hand into the car to dump into the change tray, I may as well put the key in the ignition, right? I want to unlock the doors from ten yards and put my keys back in my pocket before I need to use my hands to open the door, put the laptop/coffee down, etc. defeats the purpose!

Definitely thought about it, though!


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## Whiterabbit (May 26, 2006)

now here is a question, I see an ebay ad for a 24 inch range RFID which is perfect! five times more expensive though.

However, it looks like the only difference is the pickup antenna is a 12" hoop instead of a 1 inch hoop. Could it be this easy? simply buy the 3 inch range RFID, cut off the small antenna and use some wire to homemade wrap up a larger antenna?

For $26 shipped we can buy two RFID. One 12" homemade coil can fit in the drivers seat, a second in the drivers backrest. No matter where your RFID is on your person, it would sense.

chad, arent you a radio enthusiast? are you familiar with the science behind these pickups and how range works? is it just like a metal detector where the hoop size dictates the usable depth range?


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## chad (Jun 30, 2005)

Whiterabbit said:


> but if I am gonna carry the keys by hand into the car to dump into the change tray, I may as well put the key in the ignition, right? I want to unlock the doors from ten yards and put my keys back in my pocket before I need to use my hands to open the door, put the laptop/coffee down, etc. defeats the purpose!
> 
> Definitely thought about it, though!


I feel exactly the same, but the cubby idea will get you on your feet till one can find an appropriate long range unit.

As for auto start, I can't do it in my app because it's a manual transmission car.


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## bretti_kivi (Dec 3, 2007)

thoughtfood: http://www.cravediy.com/index.php?/archives/40-Keyless-Entry.html


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## Whiterabbit (May 26, 2006)

what chad? you've not solved that one yet? Come on, that is interlocks 101!

you buy a magnetic reed switch from radio shack for $4.99. it is a barrel that fits perfectly inside the larger hole in plumbers backstrapping. Double up the strapping into a piece about 3 inches long and screw it into your shifter assembly, facing the reed switch to the pivot for one of the linkages on your shift stick. Then epoxy a neo magnet onto that pivot rivet. It takes some positioning, but you can make it sense in neutral but not sense in first or second, and not collide with the switch when dragging the stick over. 3rd and up arent even on the radar.

There is a star ground just under the stick I bet you know ALL about it. One line gets tapped to that from the switch. The other side (ONE wire only) gets run up to the underdash and is shorted to the clutch sensor.

Now your clutch is bypassed ONLY in neutral (and doesnt interconnect to the alarm AT ALL and requires NO relays). The key will start the car without the clutch in neutral, and remote start will operate in neutral. If you park on a hill or leave the car in gear and forget about it, the key wont start the car, nor will remote start. It'll fault out the starter. But sitting in the car in gear, you can still activate the clutch and key start the car. (or remote start it, but that would be kind of weird, you know?)

By the way bretti, that little "mod" is classic. ha!


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## Whiterabbit (May 26, 2006)

requires one switch, 3 inches of backstrapping, one screw, one magnet, one wire, one ring terminal, and one T-tap.


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## chad (Jun 30, 2005)

Yeah but I leave it in gear with the e-brake pulled. it's an old habbit that I'll probably never break :blush:


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## Whiterabbit (May 26, 2006)

oh, you'd be surprised. Not only how easy it is to "break" the habit, but how it kicks back in without even thinking about it when parking on a hill. Only "habit" that got me was hitting the remote start in san francisco when parked on a steep steep hill, and not recognizing for a split second why the car didn't start.


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## chad (Jun 30, 2005)

Even worse, we don't even have hills! None, nada, flat as Danica Patrick.


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