proximity device needed

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- Phil in Melbourne
  
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posted
16 years ago

Fri, Jul 20, 2007 4:16 AM

The Toyota Prius has a key that does not need to be produced in order to get into the car. You just have to have it in your pocket as you come close to the drivers side door. It will let you in, and you can start the car (via pushbutton) and go.

This is a great feature that I want to replicate for my house. I dont want to fumble around for my keys so I want something that I can just have on my key ring. Is there a kit that I can buy that has this functionality?

I have seen these clips for PC computers too. They lock your PC if you go further than about 5m away from it. What is the operating principle for these things?

I really dont want to be changing batteries often. I assume that the cheap PC locking devices are constantly transmitting a low power signal, but I assume that the Toyota Prius device is a lot more complicated and ingenious.

I cant seem to find much technical info on both products.

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- David L. Jones
  
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posted
16 years ago

Fri, Jul 20, 2007 5:40 AM

Probably just an RFID tag of some sort. The tags are passive, getting their power as they enter the RF field, so no batteries required. My home alarm system supports RFID tag readers for arm/disarm and door strikes etc, but I don't think the range is good enough to leave it in your pocket.

Dave.

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- Joe G (Home)
  
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posted
16 years ago

Fri, Jul 20, 2007 9:47 AM

Close, It's RF + RFID called PKE (passive keyless entry) rather then RKE (remote keyless entry).

With car's specifically - there are 2 parts to the design challenge a) Remote device that uses RFID receiver and RF transmitter....... using minimal power so the key remote device has 2~3 years battery usage be) Car RFID transmitter and RF receiver ... using minimal power so the car battery doesn't go flat.

For your requirement ..... a long range RFID reader connected to the house power and passive RFID tags (no batteries required).

**** The problem is long range RFID readers are expensive.

When I mean i) Expensive ==> $600 + ii) Long Range RFID reading ==> 700mm +

So long range RFID reader == expensive.

Joe