E Tag - Diy Reader Module


Senior Member
i've recently aquired the need to read Etags (for those who are still living under a rock i mean the tagging devices that are in widespream use in practically every city bound car in australia)

to be specific a friend of mine who is a service station owner is being hit hard by the never ending petrol driveoffs, after reviewing the many many hours of cctv video, (still uses long play vhs tape), which the police not very usefull with because of the stolen number plates, one thing we've noticed is that around 90% of the offenders the 117 odd in the last 12 months have yes changed to a stolen number plate, but have neglected to think about their etag,..... which i think poses an interesting but somwhat technically challenging project, an Etag Reader
has anyone got any experience and or thoughts on the matter


Senior Member
Isn't the use of centrally controlled gas pumps a simpler solution (albeit perhaps more expensive initially)?

The typical gas-and-go station in the US has a credit card reader at each pump (which wants the billing zip code of the card holder) and a central kiosk where non-credit-card users pay in advance for their gas.

Even small stations typically have central control when the pumps don't include a card reader. You pay in advance with cash or credit.

In either case, there are no drive-offs.

Reading the toll tags requires knowing the frequency(ies) used and the protocol/encoding used, things the toll authorities are not likely to hand out to just anyone. Remember that a Bluetooth PDA can run software to break into a Bluetooth phone, download the phonebook, and in some cases get the IMEI number.

If there are any decals (local taxing authority?) on the windshield (windscreen?) than any readable numbers might be of value.

Perhaps a large EMP generator that can power up a coil at the end of the driveways? ;-)
The vehicle is stopped, the culprit is immediately prevented from fleeing by car, and all the electronics must be replaced. "But Dad, it was just $10 of gas!" "No, it was $2800 of control computers. Now get out there and get to work!"



Senior Member
problem is over here as soon as you do people tend to winge and complain, then starting using the servo 100m up the road,

i would image that there is some kind of standard in place because you can use the same tags across various motorways(aka highway robbery points)

i would laugh if these things are readable by a reader module from jaycar or somthing like that


Technical Support
Staff member
The typical gas-and-go station in the US has a credit card reader at each pump (which wants the billing zip code of the card holder) and a central kiosk where non-credit-card users pay in advance for their gas.
In the UK it's fill-up then pay. It's a cultural and familiarity thing I suppose, though tank size and driving habits play their part. All Brits I know follow the practice of filling the tank to the brim so they don't know how much that will cost in advance. Then there's that resistance to paying for something up-front and fearing not getting what they paid for plus the problem of having paid for so many gallons of fuel and finding the car won't take that much.

As DPG notes, if people don't like the way one station does it, they will use another.

On the tag system, it seems this is just RFID on a larger scale and should use standardised protocols, but whether the protocol documents and associated equipment is available is a different matter. On protocol complexity, I suspect a lot depends on how the tags work; whether they only broadcast information or whether they can be updated and hold information. If the later there's probably a more complicated protocol and security involved but even so the broadcast information may be accessible.

Whether it's legally allowable to 'track' someone's vehicle this way is something you would also have to investigate. If you can, it may still not be much use, practically or evidentially. How do you prove a particular car has the registration you claim it has or know which car is providing that registration number ? Even if you are convinced by what you get, gives a indication as to who the police should be checking up on, will the police do that ?

It's probably worth talking to the police before spending money on developing or implementing your own system. As the technology is available it may be that they or other authorities could provide it or know who does, but that ( or any noted success you had with your own equipment ) would likely lead to others doing the same and those stealing gas turning their eTags off.

If it did work, it would work in other situations where drive-off fraud can happen, so the obvious trend would be to put such readers everywhere. That then leads to the 'privacy debate', what people consider acceptable or reasonable, how much of a 'surveillance society' is deemed okay. This means, even if you could and had good reason to do it, is it morally right to do so ? - A potentially contentious debate with no single answer which isn't best pursued on this forum.


Senior Member
acording to the solicitors they are really just like any other rfid device and there is "no contractual or legal requirement" to have them attached to your car when not any applicable motorway, if read on private property they are akin to taking a number off a number plate,

i'd rather avoid the lengthy debate on the morals and ethics of doing it , but while the general population of australia keeps voting for "dictator wannabes who bring in more and more draconian privacy and rights eroding legislation"
and continue to push line "if you've got nothing to hide, you've got nothing to worry about" to justify it,... i don't see why it should stop me especially if it's costing me and /or my friends money, if the various dictators of the world can live with that sick little feeling in the tummy then so can i, after all isn't it a priority to put food on your table first