able to drive prius without key in dash-- and i don't have a smart key system!

The fob uses RFID, which requires it to be near the slot. It does not make electrical contact inside the slot.

Tom

 

so this means after you start you can pull the FOB out at any time? might be handy if you stop somewhere and dont want to turn off the car for a quick "run in and out" locking the car is usually recommended

i had a 2004 that required the Fob to be inserted but that was many many moons ago and never tried it.

 

But why the surprise. As qbee42 stated, the car only requires the FOB to be inside the car, where RFID technology senses it; the FOB slot is just a convenient parking space for it while driving. I never use it on my 2008 Prius, I simply keep the FOB in my pocket before pressing the Start button.

Incidentally, you cannot drive fobless. The FOB has to be present inside the car before it will enter the Ready mode. Not necessarily in the slot though.

 

That only works for SKS. The RFID inside the fobs is very short range. It needs to be within inches of the antenna; keeping it in your pocket will not work.

The non-SKS fobs only have RFID. The SKS fobs have both an active transponder for the smart system, and RFID as a backup.

Tom

 

As a side note, on my 2005 Prius with SKS, once I start the car, I can take the smart key fob outside the vehicle, and I can still drive the Prius away. It will still beep and show the dash light, but I can still put it in drive from park, and it seemed to work indefinitely.

Perhaps the Prius only needs to ensure the key is in the car at startup, and then it doesn't care where the key is?

 

My old K5 blazer could be started with the key removed from the ignition, as long as it was not in "locked" position. I used to leave the ignition unlocked most of the time so I only had to use a key for the door.

 

Yes, as I wrote my comment I suspected that a fob without SKS might have different characteristics.

Thanks for the explanation, Tom.

 

Some Jeeps were like that too. It is very handy when you live in a safe community.

Tom

 

Correct. Requiring the key to drive is considered a safety issue: What happens if the fob battery dies when driving down the road? What happens if RF interference jams the signal?

Tom

 

Seems to me that someone with a little electrical knowledge could probably mod that RF reader with a boosted signal so that non SKS could be read further away (IE from inside your pocket)

 

dont you have to boost the FOB? a receiver is just that... a receiver. it like catching a ball from someone standing 100 feet away who can only throw 50 feet.

nice idea but the thought of changing the battery every 6 months is not appealing

 

Not sure how the RFID in the Prius Fob works, but in many RFID applications there is no battery connected to the RFID chip.

In RFID applications without a battery (such as in the chips imbedded in pets) The reader sends an encoded radio signal to the RFID chip, the changing magnetic field of the radio wave induces an electric current in the chip. This induced current is used to transmit the encoded RFID value back to the reader.

So, if this is how it works in the Prius FOB, then you would have to modify the reader to send a strong enough signal to induce enough current in the RFID chip at the significantly increased distance from the reader. Then you would need the RFID to transmit back a strong enough signal to the reader. Perhaps adding an induction coil (or improving the one that is there?) to the RFID chip?

You could reduce the power needed by moving the RFID reader closer to your pocket. Maybe install it in the center console? or in the driver seat?

 

ah sooo??? ok. sounds like it would be a huge boost in signal to a completely different format i am guessing. isnt RFID used extensively due to its cheap cost? this would definitely realign the price to something probably close to the SKS prices

 

I have an '06 Prius and I have to put the FOB in the slot to start it, and after it's started the FOB won't come out. What does this mean? "True Dave, even offers the option of disabling the lock mechanism that holds the key in to allow you to do that."