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Long story short: They stole my bike. This is the fourth one; apparently it doesn't matter how well you secure it, if they want it, they'll take it.

Now, the police actually caught them after a couple of days. But I cannot get my bike back because I cannot demonstrate ownership, what with bicycles being not registered and (in my case) lacking any identifying mark. They need more proof.

Idea bulb. What if, in my next bicycle, I place a series of well-concealed passive RFID tags containing information and perhaps codes only I can possibly know? That would constitute enough proof to the police and they would probably release my property without much fuss, once explained the situation. I know I'm geeking out, but it's plausible.

Do you have any suggestions as to how to proceed? Pros? Cons?

I basically need some programmable RFID tags and an RFID reader but I honestly there are so many I'm a bit confused. Any help would be appreciated.

(Of course a GPS system would be ideal but a bit of overkill for a €150 bike - and anyhow, the system should ideally draw no power whatsoever - passive - and stay as stealth as possible.)

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Wouldn't it suffice to take a photo of the bike before it's stolen? – avakar Nov 12 '11 at 7:49
Honestly in my opinion something like this doesn't require a "hi-tech" solution. Just take a picture of the bike and write down the serial number of the bike somewhere. Even better is to stand next to your bike holding a paper with your name and bike serial number clearly written on it while taking said picture. – In silico Nov 12 '11 at 8:02
Also, you may be interested in the Bicycles Stack Exchange site, which seems to be more appropriate for this kind of question. You might even get strategies on how to lessen the likelihood of your next bike getting stolen. – In silico Nov 12 '11 at 8:09
@avakar: Certainly it would have helped a bit, but no, I don't think it would've changed much - unless we're are talking about a custom bike, one that it's obvious is yours. It's either a very unique distinguish mark, or A RFID tag with some info - that would be Grade-A level proof - try to contest that. insilico: as far as I know, there's no serial number in that bicycle. It's been handcrafted by a local enthusiast who owns a shop and ASAIK bikes don't normally have serials. But thanks for the suggestions guys, I'll visit the Bycicles Stack Exchange immediately. – Mark Nov 12 '11 at 8:19
get your phone number or name engraved on the bike, preferably somewhere less than obvious. Sometimes simplest is best – Journeyman Geek Nov 12 '11 at 8:51

You are using a sledgehammer to swat a fly. Bike frames have serial numbers already, usually underneath the main crank. When you first get your bike, record the serial number. If you can provide that to the police, they can easily check it and verify it's your bike. Even better, when you buy the bike, make sure the serial number is written on the receipt, and keep that around like you do for other valuable items. Taking a picture can't hurt.

Sometimes old fashion methods are perfectly fine and more robust than fancy high tech new ones. Stamped serial number beats RF ID.

However, I am surprised the police are giving you this much trouble about returning your bike. Usually the make and model along with some identifying mark is enough. If you've had the bike for a little while, there will be a scratch some place, a part you replaced, a special quirk, etc. Perhaps they can release it to you if nobody else comes forward to dispute onwnership after two weeks or so? What are they going to do if nobody can prove ownership, but one person comes forward to claim it?

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@Mark: If your bike is only a week old, surely you have some kind of proof of purchase (receipts, invoices, order forms, etc)? Or even track down the person/store you bought it from and ask for some kind of documentation. – In silico Nov 12 '11 at 22:28
I have a receipt, and they certainly logged the purchase in a ledger, but they didn't take my name/surname and I don't see how whatever extra document they could supply me with would be of any help. Considering the red tape, I suspect the cost of my time is actually not even worth the whole ordeal. – Mark Nov 12 '11 at 23:00
@Mark: I would imagine just having the receipt in hand should be sufficient? Especially if it has some kind of description of the bike on it. And if you paid by a credit/debit card or a check you can link the receipt to you actually being the one purchased it. – In silico Nov 12 '11 at 23:10
@Insilico: I doubt it, since the receipt doesn't even mention that the item is a bike; it just lists it as "Item 1"! So, though luck... (Fun fact: The "Item 2" was the chain.) – Mark Nov 12 '11 at 23:50
The police is giving me this much trouble because they didn't just find my bike; they bust a entire circle of bicycle thieves and found in the neighborhood of 100 bikes in their thieves' den. My bike just happened to be among these, but since I didn't report the theft in time, it now constitutes "body of evidence", and so we have to wait for the trial. Besides, I have no proof in my possession. I didn't take the serial number (don't even know if it had one), didn't take pictures, the receipt doesn't even mention "bicycle" anywhere let it alone a description... imho, it's gone for good. – Mark Nov 13 '11 at 0:00

Adding RFID tags to your bike is the same as adding your own personal secret serial number to it. That would most defiantly prove to the police that it is your bike.

If you wanted to do this, I'd suggest using Parallex's hobbyist tag reader in conjunction with their world tags. Use the world tags because they are unique. The same parts are also available at Digikey.

For interfacing them, they operate on a 2400 baud serial port. An arduino will be likely the easiest way to interface with them. There is plenty of sample code and full programs out there that you can just plug and play with (just dig around a bit).

Be aware though, RFID tags don't work very well if there is any sort of metal around them so hiding the tags in or on the frame won't work...unless of course your bike is graphite epoxy.

Now for the practical part. As stated in previous answers, this idea is overkill, a simple picture on file would do just fine.

Now to address other people's answers. For all you experts out there, if you come across a question that is sounds silly to you (but has no potential safety concerns), please do one of the following:

1) Answer the question seriously and then add a section at the end to point out the obvious issues. 2) Don't answer the question at all.

Unless the question being asked could lead to potentially dangerous results there is no reason why you should be telling the OP what he or she should be doing instead. Offer an answer to problem as you would any normal question AND THEN properly solve their problems the "right" way. Who knows? maybe the OP asked the question with an idea just to learn about a new technology so that they could use it in other projects.

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Consider that it may take some effort to explain the RFID setup to the police department if they aren't familiar with that. How would an already apparently skeptical officer know that the "reader" the claimant supplies is detecting a tag that's actually on the bike, and not "finding" it (or not) based on some secret control? Something they can verify with their equipment (eyes) rather than an instrument supplied by the claimant is probably preferable. And cheaper. – Chris Stratton Nov 12 '11 at 19:56
Absoloutly, a picture will more than suffice in this situation. However, this is an electronics Q&A, thus the issue with using the RFID technology should take precedence over exactly what is is used for. Lets answer the question about the RFID and then comment on the application later. – Faken Nov 12 '11 at 20:29
Faken, I really appreciate your comments above. I would upvote you but I don't have enough reputation. True, I was just tinkering with the idea of RFIDs and I would have probably ended up not doing it. But: 1. Your links gave me exactly what I was searching for so in case someday I'll want to try my hand at at it (seems pretty cheap too); I will. 2. You're right, what started as a simply "They stole my bike" thing made me delve deeper into the world of RFDIs and came up with tons of possibilities. To all the others: I also appreciate your comments too, don't get me wrong. – Mark Nov 12 '11 at 21:35
@ChrisStratton: You have a point. I admit that I'm overestimating the police here - I wouldn't certainly deal with the CSI computer boffins - the "contraption" (the word they would likely use to describe the equipment) wouldn't probably be acceptable because it's "non-standard", "homemade", because they cannot verify how it works, yadda yadda...basically, police speak for "I ain't going to spend this morning arguing with this dweeb about things I don't understand". Heck, they might even reprimand me for using "unauthorized radio equipment". – Mark Nov 12 '11 at 21:44
I wouldn't say overestimating - there probably are police departments or at least officers within them that are very enthusiastic about RFID asset tagging. But a complicated personal scheme that relies on a positive official reception may not be the best idea when there are simpler methods. – Chris Stratton Nov 13 '11 at 0:04

Like Olin says you're thinking of too much technology. The serial number is a solution.
For time to time the police in my town organize an event where you can have your bike engraved with your social security number (see edits) in a clearly visible place. So far no stolen bikes. Selling your bike will force the new owner to engrave it as well, though.

Many moons ago in BBC's Tomorrow's World they demonstrated a new way to mark cars' parts to identify after theft. It involved spraying the engine block with tiny, sticky IDs, IIRC less than 1mm long with the ID printed (etched, ... whatever). The idea was that you can remove 10 or 100 of those, but not thousands. Obviously you needed a microscope to read the IDs.

edit following Kevin's comment
Maybe SSN is a bad translation of what in Belgium is called your National Number (NN). The NN is a code consisting of your date of birth, a counter for that day, and a 97-check number. I've never heard of identity theft through use of an NN. And if I would commit identity theft, it's easy enough to invent a valid NN: 901112-001-54. That's the NN of a man (because 001 is odd) born on 12 November 1990. You can't do anything with it, because you don't have his electronic identity card.

OK, so the SSN is not a good choice if you want to keep it for yourself. As an alternative you can create just any code, like a password. You show the police the paper on which you wrote it down, and they can tell it matches with the code on the bike. I mentioned marking on a clearly visible place, so that would-be thieves can tell it's marked.

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Engraved with your social security number? Wouldn't that encourage both bike and identity theft? – Kevin Vermeer Nov 12 '11 at 18:22
@Kevin - Yes, I thought that question would pop up, but where I live it's just a combination of a date of birth and a number. If you're after identity theft you might as well pick such a number at random. I've never heard of identity theft here due to making your SSN public. In the US YMMV. – stevenvh Nov 12 '11 at 18:31
@Stevenvh - in the US - a social security number is considered by some to be 'secure' - so it can be used to provide proof of identity for certain things. While simply getting a SSN number is not the whole process of stealing an identity - its certainly a valid initial step in stealing a specific identity. – rfusca Nov 12 '11 at 19:51
Steven, evidently up there in Belgium you give bicycles the respect they deserve. Where I come from (Italy), not so much. I often feel barely tolerated. If engraving is the way to go, I would choose a personal code of some sort. ID numbers or their equivalents are too risky; in Italy the Fiscal Code can easily be used for fraud. My choice of RFID is not a fixation with technology per se of the "give me tech or give me death" stripe, but rather trying to being shrewder than the thieves. Seriously; were you a thief, would even think about searching for RFIDs? – Mark Nov 12 '11 at 21:25
@Mark: If you bought it just a week ago, surely there is still some paperwork around from the transaction. Even if you didn't keep a receipt, whoever you bought it from either has records or still remembers you. Unless someone else also claims your bike, getting it back from the police really sounds like a solvable problem. After all, this can't that different from other stolen property they recover. Surely they have a normal way to dealing with this that mostly works. – Olin Lathrop Nov 12 '11 at 22:04

I think a really low tech solution (not my original idea) is imediately after buying it to make a copy of the proof of purchase (with your name in it). After that remove the seat and introduce your proof of ownership, protected from weather (water, rust, salt, etc), into the shaft. Put the seat back. Don´t forget to report any event to the authorities. Buy insurance (Just kidding).


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Did you ever heard about Bike Sheperd?

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The http://www.crookedbrains.net/2014/11/coolest-smartphone-bike-locks-trackers.html page has also a nice set of anti-bike-theft technological solutions.

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Nfc anti metal tag sticker. Encode with name, number, email, a basic contact card. If the cops are skeptical, any decent android phone or iPhone with nfc can read it.

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