Thread: RFID-Based Auto-lock/unlock System

Originally Posted by Mark_MES

Keep in mind that companies follow the specifications put in place by the OEMs and outside of aftermarkets versions, no one really offers a long range RF since the OEMs won't use them. The EU has standards for RF and it's a fairly short distance, around 27cm if I remember right.

-Mark

That's only true if you are trying to duplicate a system using available RFID tags and the low frequencies used for them. Anything that uses RF to communicate with a device and uses encrypted keys for authentication is still an RFID device but not in the sense of the now current definition for that standard. Long range devices are not energized by an RF field and would use frequencies in the allocated UHF and 2GHz range with the Tag self powered. The tag initiates the communication link not the other way around as with standard close proximity RFID systems.

I may have actually found an alarm that might work but may require some reverse engineering if I can't get them to let me have access to the protocol.

Apparently there is a version of a Viper alarm (By Directed) that allows you to access ODBII information as well as the current alarm states and digitally setting of sensors, GPS and a bunch of other stuff. if I can interface directly into it with a computer and not require a service contract it may be worth it to use that alarm and just add some features to it.

There otherwise is an android app and you have to get a service agreement for it. I will likely try having an ARM based computer access it so I can put up a web server that can display an interactive HTML5 screen that displays all of the information needed.

I've had a few different exposures to passive RF ID tags and I though I would share my experiences.

First off, I have set up two different access control systems that use passive RFID chips. In one system, we use small key fobs. In the other system we use badges with the chips imbedded in them. The fobs and the badges both use the same technology and in fact could be used interchangeably if it was so desired. Th range on them from the tagged device to the reader is about 2-3 inches at the most.

My other exposure was in the form of the implantable chips that many people put in their pets. Most of them wind up in dogs. In my case, I put them in my llamas. Anyway, the "chip" is inside a small glass tube, maybe a bit under 0.1 inches diameter by 0.5 inches diameter. The reader is a hand held thing with a pickup coil about 5" diameter. The range is only a couple inches max.

Passive has advantages... no batteries to ever replace, but I am thinking for extended range it just doesn't cut it.

Rick

I would not waste my time and life with this. Just buy a 300$ kit.
I did it and works great.

Originally Posted by cederron

I would not waste my time and life with this. Just buy a 300$ kit.
I did it and works great.

$160 for a long range off the shelf device made for interfacing with Keyless entry vehicles.

I can make one for around $30, I just need to get the tag a little smaller. Some of us are playing around with standard short range RFID for other purposes and not just the Vehicle access idea inquired about by some forum users so the discussion will likely continue.


Hi Rick, yes passive devices powered via an RF field are short range by virtue of legal power limits and size, frequency and power consumption. The disadvantage with passive devices in a vehicle is the fact that the detector in the vehicle is also the transmitter for the power source to the Tag. Not good for long term power without some thoughtful design.

Powered version of an RFID Tag (totally different to what is now referred to as RFID) is perfect for long range access with virtually no power consumption from the vehicle. Tag battery life is claimed to be measured in years.

Originally Posted by cederron

I would not waste my time and life with this. Just buy a 300$ kit.
I did it and works great.

I'm all for the build-something-on-your-own-spirit that most people here have, but I have to agree with the above statement. You can piece together many different products to make something that's functional or buy a product that was designed from the ground up to do something. Like everything in life, it comes down to time and money.

-Mark

Thanks for the link Mark, but your website does not provide any information regarding price or what products you would actually receive. A shortfall of this system is that only one phone can be paired. I guess my wife will just have to walk. I also didnt see any info on as to what rage will the system lock/unlock the car. Is it when bluetooth is our of range/within range (i.e 10m)?

Originally Posted by mos33y

Thanks for the link Mark, but your website does not provide any information regarding price or what products you would actually receive. A shortfall of this system is that only one phone can be paired. I guess my wife will just have to walk. I also didnt see any info on as to what rage will the system lock/unlock the car. Is it when bluetooth is our of range/within range (i.e 10m)?

Hey mos33y, since the modules are installed by our retail partners, there is no "module only" pricing. We don't currently have any partners in your neck of the woods yet, sorry about that. A common question is about the fact that we only allow one phone to be paired at a time instead of two specifically for couples. We would love to accomodate people on this, but it opens up a slippery slope on the whole simplicity on the module. I'm not saying it will always be that way, but as of right now it's going to remain single phone per module with the ability to have one module for each person in the same car to provide the function that you're looking for. Range varies slightly depending on the phone and vehicle but averages around 5-15 feet (1.5m-4.5m) on unlock and a little farther on the lock range. We can always add range but most people are happy with the average operating range. Anything else, just ask.

-Mark