DCC Conflict Caused by Toyota Prius Key

[CSX Robert]

The newest Prius (04 and up) uses a different "Smart Start" system. According to the high voltage disable procedure, the system can communicate up to 15 feet.

Good to know. I thought the Prius was passive as in required no internal energy source and that it responded once only to a signal was sent out by a car. Thanks.

The power source does not define the system as passive or active, this does:

BTW, we refer to any transponder system, which requires no action by the driver to activate or deactivate as a passive system.

By removing the ability for the owners to "forget" to arm the system, the security of the vehicle is not compromised.

Jim

I would like to add some clarification to the passive and active descriptions. When talking about the system, passive means no action required by the driver. When talking about the RFID chip, passive means that it does not have a power source and gets it's power from the RF signal of the reader and only emits a signal when in the presence of the reader, and active means that it has a power source and periodically emits a signal on it's own.

What this means is that if you have a passive system, the RFID chip can be passive, active, or even semi-passive, meaning that the RFID chip uses a battery to boost it's range, but still only emits a signal when in the pressence of the reader.

[Vail and Southwestern RR]

The capacitor on the UPS decoder is just PART of the equasion. The capacitor DOES supply the required power for the motor / electronics.

The decoder, while separated from physical contact of the rails by a sheet of paper, is still capable of receiving commands from the controller - a power storage device alone cannot do this. There is SOME means of radiating that signal through the paper. I watched it myself - you could stop / change direction / change speed all while being totally isolated from the rails .... how is that signal transferred ???

Mark.

I'm going to have to do some research/reading....

Take a look at this page:http://www.tttrains.com/dcc/hybriddrive/
Scroll down almost to the very bootom where it says "What are the key concepts that make DCC Hybrid drive possible?" and it explains how the Lenz USP technology gets the DCC signal.

Okey, dokey.  I can see that that would work.  But it sure isn't microwaves, and it isn't going to see anything from a Prius key that happens to be in the room.  But, it makes a lot of sense as a way to improve DCC signal reliability.

 

Edited to put the response where it makes sense....

[Robby]

Okay guys, I work for Toyota and have responsibility for these parts.  Sooline is close as to how these systems work.

The basic immobilizer system which has the "chip" in the standard key is passive in that it transmits nothing until you insert the key into the ignition and power up the vehicles internal systems.  The immobilizer ECU then sends power to the antenna which is part of the light ring surrounding the ignition switch.  From here it acts like a typical inductive RFID.  The "chip" in the key is thus powered by the magnetic field generated by the coil (antenna) in the key ring light. The key's "chip" picks up the magnetic energy, and then communicates with the immobilizer ECU via the antenna. The "chip" modulates the magnetic field in order to retrieve and transmit it's "code" back to the immobilizer ECU. If the "code" from the key's "chip" matches one of the "codes" stored in the immobilizer's memory, it then sends a signal to the engine ECU that it has a valid start code.  The engine ECU next will "ask" the immobilizer for a rolling synch code which the two ECUs have previously decided upon the last time the car was started.  This rolling code between the immobilizer and engine ECU changes every time the car is started such that if someone tries to switch one or both ECU's in an attempt to steal the car, nothing will work again until the car is taken to a dealer.  Key point here is to never start unplugging wire harness connectors with the key on or your car will not be able to start again and it will cost you a dealer visit and probably a tow bill.  Information to take home with you here also is that the "chip" inside your keys only work when in the presence of the properly coded magnetic field.  This system has no affect on a DCC control system.

Car system two is the keyless entry and remote start systems.  These are the push button key fobs or the more recent in-key transmitters where the key itself has several push buttons assocated with it.  These systems are passive until you press one of the buttons at which time the in-key or key fob will transmit an encripted low power signal in the 315 MHz range.  In your car is another ECU usually mounted near the roof on one of the rear C-pillars.  This ECU is always powered up when your key is off and removed from the vehicle.  It cycles off and on to save battery power several times per second.  When it's awake, it looks for all signals in a narrow band around 315 MHz, when it's asleep it does nothing.  This is one reason you car battery will die if you don't start it once a month or so.  Many other systems also draw power while the key is off and this "dark current" gets higher with every new model launch demanding more and more battery stand-by reserves.  Now, while the receiver is awake, if it "sees" or "hears" a transmitted 315 MHz signal, it will check if the signal is coded and if the code matches one of the stored codes in its memory.  If the code matches a stored code, it sends a signal to the body ECU which then either unlocks the doors, opens the trunk or cranks on the panic alarm.  In the case of the remote start, the body ECU will first lock all the doors and ensure the windows and moon roof is closed.  It next tells the engine ECU to ignore the immobilizer ECU and start the engine.  If a door is opened by the push button remote key fob or by inserting a mechanical key into a door lock or by opening the door from inside or by stepping on the brake pedal, the engine will die and will not restart until it goes through the immobilizer confirmation via a mechanical key inserted in the ignition switch.  Many people don't like this since your nice warm car dies and has to be restarted before you can drive off in it but it ensures some yahoo can't break a window and drive off.

 

System three is the smart key or push button start.  This system is almost like system one on 'roids.  The vehicle has many antenna systems around the car.  There is one in each door handle, one in the trunk, one under the rear seat and one under the center console.  Some cars vary, the Lexus and Avalon have an antenna in all doors while the Camry and new Corolla only have an antenna in the front doors, etc, etc. The smart key fob that you carry with you has not one but two battery-powered transmitters inside and it also has a standard RFID "chip" same as the one inside the keys associated with system one.  Transmitter number one is the same as system two above and is used to unlock the doors, trunk or trigger the panic alarm via pushbuttons on the fob.  Transmitter two does not transmit unless it passes within range of one of the vehicle antenna systems which generally have an effective activation range of about two or three feet.  So when you walk up to a locked smart key car, the fob transmitter is activated by the magnetic field from say the driver's door handle antenna.  The fob transmits a coded signal which the door handle picks up and sends to the smart key ECU.  If the code matches a stored code in memory, it allows the door handle to become "active" and also tells the immobilizer to wake up the engine ECU in anticipation of a possible start command.  The doors do not unlock on their own as the old Corvette did.  The door handles are in fact smart handles which look for a capacitive coupling from your hand along a metal strip on the inside surface. When you fingers wrap around the handle, the door handle ECU senses your hand's presence and then and only then unlocks that door.  If you depress the brake pedal and press the start button, the engine ECU has already gone through it's back and forth discussion with the immobilizer ECU and the car will start.  If you do not depress the brake pedal, the car goes into an "ON" mode where the meter, radio, etc will power on but the car will not start.  In the Hybrid versions, the vehicles go into a "Ready On" mode so if you place the car in "gear" and hit the "gas" it will move.  Now, if the smart key fob battery goes dead, you can still drive your car in emergency mode.  There is a little mechanical key inside the smart key fob that can be removed and used to unlock the driver's side door manually.  You can then hold the smart key fob up to the push to start button which has the same antenna coil inside as the key light ring in system one above.  Press the push-to-start button and the antenna powers up, a magnetic field is generated and the RFID code is transmitted which allows the car to start and be driven.

 

SO, for smart key, the only way it will ever transmit is if you press the buttons and activate the 315MHz keyless entry system or if you pass the fob within a proper magnetic field which will activate the 318MHz smart key transmitter.  That said, I have nine different versions of various Lexus and Toyota production and trial smart key transmitters with me and a test receiver that beeps if it sees a transmitted 315 or 318MHz signal.  I also have a Digitrax DCC system with radio throttles in the basement.  Try as I did, nothing associated with the Digitrax system would force any of the smart key transmitters to activate and transmit.  I tried placing the fobs on the tracks, on top of engines and next to the DT400 throttles....nothing.  I next ran two sound-equipped C-420s and two Digitrax decoder-equipped C30-7's around and around while pressing each of the keyless entry buttons on the smart key fobs.  My detector chirped like a little bird but none of the locos missed a beat.  I then tried the standard keyless entry transmitters from my Tacoma which are actually around 313MHz since they are aftermarket versions with no affect to the Digitrax system.  Finally, my wife just got her new smart key Highlander yesterday which has the newest smart key fob design and it had no affect on the DCC system.

 

RESULT: MYTH BUSTED

 

[selector]

Anybody have a bottle opener?

[pastorbob]

Well, if i can't blame my keyfob, and I don't drive Toyota anyway, I can blame a lot of other things for my NCE Radio system having problems at times.  NCE uses the 900 mhz range, and as I have found out the hard way, so does my telephone in the train room, the intercom system between the downstairs and the main part of the house, and at times, other unexpected goodies.

Love the system, but during any operation, the phone is disconnected, the intercom is turned off, and I hold my breath.

 

Bob 

 

[cacole]

Well, if i can't blame my keyfob, and I don't drive Toyota anyway, I can blame a lot of other things for my NCE Radio system having problems at times.  NCE uses the 900 mhz range, and as I have found out the hard way, so does my telephone in the train room, the intercom system between the downstairs and the main part of the house, and at times, other unexpected goodies.

Love the system, but during any operation, the phone is disconnected, the intercom is turned off, and I hold my breath.

 

Bob 

 

 

I think ALL wireless DCC systems are required by the FCC to use the same frequency range.  DCC manufacturers can't decide on their own to use a certain frequency, it must be assigned by the FCC and their wireless systems must comply with FCC rules and emissions testing.

I have two wireless DCC systems, the North Coast Engineering ProCab for my indoor HO layout, and the CVP Products AirWire900 for my outdoor G-scale trains.  Even though both use the 900MHz range, they are on different frequencies within that range and do not interfere with each other or with any other devices.

 

[G Paine]

RESULT: MYTH BUSTED

Robby, thanks for your in depth description of the Toyota smart key systems and for yor testing, but the fact remains my non-radio Digitrax Super Empire Builder system did not work when my nephew with his 'system 3 key' was standing near it and it did work after he left. Maybe he had something else that interfered.