Is there a proximity sensor inside of key handle?

2017 Subaru Outback
Wanted to get a duplicate key made. The store said they could not cut a spare key because a chip inside was required. That is, the chip or
sensor had to be in proximity of the car for they key to work. I don't agree (for this car).
I used the extra key that came with the car. It has no buttons and also no battery. I left the buttoned+batteried key in the house and went out to the car with the non-electronic spare key. The car started okay. The spare key has an oversized handle on it but no way to open to replace a battery.
Does this car's keys actually have a sensor or chip that prevents copies from being used to drive the car? This car does not have keyless entry. You either use the key to open the door or the buttons on the master key to activate the radio to move the solenoid. There is no Start Engine button in the dashboard. The car is started using the traditionally positioned ignition key component in the steering column.
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On 7/17/2017 5:31 PM, VanguardLH wrote:

I mentioned the bulkiness of the chauffeur type key to saleswoman and said I like to carry that as a spare in my wallet and might chop it down. She said not to do it because if I did the key would not work.
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On Monday, July 17, 2017 at 11:31:15 AM UTC-10, VanguardLH wrote:

The car has the standard immobilizer system. This has been in cars for ages . You have to have a key that has been programmed for your car. You can pro bably use a duplicate key to unlock the door but it won't start the car. We ll, you can start the car but it'll die when in the run position.
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On 7/17/2017 5:31 PM, VanguardLH wrote:

Not a proximity sensor but a transponder. Does this help?
https://en.wikipedia.org/wiki/Transponder_car_key
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John McGaw wrote:

Since the transponder enables the ignition when in proximity of the vehicle, how is this not also a proximity sensor?
Since the key doesn't have a battery, I was confused how its transponder gets power so it can transmit its signal. According to the article, it's the car that uses power to detect the magnetic encoding inside the key. So even that battery-less spare key has a transponder so the ignition will work when it is close.
Darn technology getting in the way. I wanted a flat key on my key ring instead of a huge bulge from carrying 2 of them: one for my car and another for the other car. They must think all drivers are women carrying purses and tote their keys on a lanyard around their neck. I used to have wallets that had a key holder. Worked great with flat keys so I'd have a spare just in case I locked the keys in the car.
Thanks for the clarification. Might put the 2nd car's spare key inside my car and then just have my car's key on my key ring. That way I'd have a spare around when I needed to move or use the 2nd car. Keys have a way of disappearing when inside the house when "cared" by other family members: too lazy or forgetful to put the spare back on the key rack.
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On Monday, July 17, 2017 at 5:44:54 PM UTC-10, VanguardLH wrote:

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I don't believe that the key senses anything. The transponder does not have a battery. A coil near the ignition lock supplies power to the transponder . My assumption is that the transponder is powered up when it's near the ig nition and initiates starting by sending a code to the computer. The sensor is in the car.
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wrote:

100 % correct. The car inductively powers the chip in the key which then sends it's code to the car. The computer either recognizes the code and starts the car, or doesn't.
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Because a proximity sensor works differently

Not quite. You've heard of wirelss charging for cell-phones? This is similar. A high frequency AC (basically a radio signal) sends a low powered signal from the car. The key has a sophisticated version of a crystal radio set in it that picks up the signal and rectifies it to provide power to the RFID chip in the key, which sends it's code back to the car. The computer in the car is programmed with the id of the key and says "yes, I know and accept that key" and allows the car to start and run.

The flat key will still let you in - it just won't let you drive the car.
What some people have done is tape the transponder key inside the steering column, and just use flat keys to drive the car. Yje chip key just needs to be close enough to the "broadcast antenna" to wirk.

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So you opened the door by putting the key in the lock, not by pressing a button? Then put the key in the ignition and started the car? I thought if you went through that sequence the car would start honking the horn unless you went through a sequence to disable the alarm.
Patty
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Patty Winter wrote:

There are no buttons (and no battery) in the spare key. There would be no way to press a button to gain entry using the spare key. See McGaw's reply on how the keys work.
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[unneeded quotage deleted]

Right, so without a battery, is the transponder sufficient to disable the alarm? As I said, I thought I'd been told that if you use the key directly to open the door, you had to do something subsequently to avoid the car honking.
Patty
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On Monday, July 17, 2017 at 7:47:38 PM UTC-10, Patty Winter wrote:

ght

The transponder does not disable the alarm. The keyfob, however, does have a battery and is a radio transmitter. The transponder is a passive device t hat doesn't do a thing until it's powered up by a induction coil in the car . Pet microchips and RFID devices are passive devices that rely on external power sources.
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Patty Winter wrote:

I don't have a keyless entry system on my car. You either use the key to open the door or the radio in the key to actuate a solenoid in the car to open the doors.
Maybe starting the car within a short time after opening the door with the key is what keeps the alarm from sounding. I've never kept track of how long between opening the door with the key to how long I insert the key into the ignition switch (which, according to the wiki article, is where are the coils to energize the transponders inside the key to identify the correct key was used to start the car).
Of course, it's possible the alarm system isn't even enabled in the car. That might depend on how many times you tap the Lock button on the master key with the battery and buttons.
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On Tue, 18 Jul 2017 05:43:40 -0000 (UTC), Patty Winter

If you unlock the door WITHOUT either the key or (if equipped) the remote, THEN the alarm beeps. Lack the car with the window down, and then open the door through the window - it should alarm
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Okay, I checked my owner's manual. It turns out that it's really easy to disable (or prevent) the alarm: you just put the key in the ignition. No "sequence" needed.
Patty
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