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By jjinno
My g/f just had her bike stolen, and I want to figure out a way to find the bike next time (cause she lives in a high bike-theft area). So I am up for some crazy ideas, as long as they fit inside the shaft of a bicycle... and I suppose this does mean I am willing to weld/cut.

My idea was to buy a prepaid cell phone, that you can add minutes to from the internet (pretty much any of them). Hack it down to just the circuitry, add additional lithium battery backup, get rid of the LCD, and insert... only problem is that you would have to have a warrant to release the phone records (H.R. 4709 - G.W. Bush) (

Any other brilliant ideas?
By Krogoth
I wouldn't have thought a bicycle would be worth trying to get access to government systems to trace phones... your bike would have to be implicated in a murder or something before anyone would even consider letting you check that.

The easiest solution (the way you're thinking of doing it) would be to add a microcontroller and a small GPS receiver, and connect the micro to the phone using its debug cable. Program the phone to send its gps position by SMS when asked, or something. Most Sony Ericsson T-series mobile phones can be easily interfaced to. However you're looking at about $150 in parts.

The easiest solution, period, would be to invest in a bike lock? :P

By daemondust
You might look into the GPS dog collars some places sell online. Or, you could build your own.

Most cell phones have a serial port on them, though newer ones are replacing that with USB. You could put a uC on that and have it power up a GPS receiver (to save battery) and reply with the current position.

There's also Disney Mobile that's set up to let you see where your kids are. That might be worth it if you need a cell phone for yourself too.

Your other options could be investing in a good bike lock, or making it ugly enough that thieves will pass it over. Remember, a lot of security is making yours less attractive to a thief than the next one.
By jjinno
The only reason I had suggested an implant system was for the "bait" operation, allowing that if the bike were to be stolen, it could be recovered and the individual served at minimum a misdemeanor, if not a felony...

The bonus is that because of all the electronics, the value of the property (bike) probably exceeds $400, bringing it to a Grand Theft charge versus Petty Theft.

I personally just like the idea of vindication. :D

Especially when I can get them AND get the bike back...
By HakBot
How about something that doesn't use a cell phone? I was thinking some kind of motion sensitive alarm. When the bike moves and accelerometer attached to the bike would send a signal over a wireless link to alert you when someone has moved it.

You could also use a gps that sent back its current coords. If the coords change from some set position it alerts you.

or both....
By silic0re
Hmm, I was thinking similarly to everyone else here. I really like the idea of a prepaid phone that you can remotely add minutes to. A low-power microcontroller, GPS, and a datacable to the phone would be ideal, so that the phone could send SMS's or, even better, an e-mail to a dummy account. You could have the microcontroller poll the GPS every, say, 10 minutes, and once an hour send an email to an email account that had the last 6 location readings in it. That way it keeps the transmission time to a minimum (saving cost on using the phone's service), but also gives you a pretty accurate idea of where the bike is and has been with a reasonable temporal resolution for catching a thief when he has the thing stowed somewhere.

I can see two potential issues, one of course that you've already outlined -- you've got to fit everything into the bike. The other one would be powering the whole thing. Lots of phones have standby times on the order of a week these days, and if the microcontroller and GPS could be put on a battery that would run about the same, that'd be ideal. You could of course try and have a little solar charger or something on it, but then you run into the issue of having a solar panel on a bike, and I'm sure the thief would get suspicious. I was thinking that you could probably fit the whole thing in the hollow area inside/around the bike seat, and pad everything nicely to make it fairly shock resistant, waterproof, and inconspicuous. You could also conceal a little power jack that you could use to recharge everything, but you'd also have to have some way of determining when the power is low.

The whole setup would probably be on all of the time, so periodically you'd have to go in an empty out the e-mail account (assuming the bike was still in your possession, of course).

By daemondust
The thing about a cell phone is that you can get a signal virtually everywhere. You could use a two way pager for the same thing and it would probably be cheaper.
By velocet
I have been putting together a unit for something similar to this, the original market was for motorcycles and we added a 3axis accelerometer so G and/or lean angle can be logged as well as your journey to the on board Micro SD.

I started of with the phone route but trying to get hold of the same phone every time was a problem and more often than not the batteries were faulty, I also found that the tracking services were less than accurate just giving you a general area, I don’t know if this is better over sea’s.

So the phone was dropped for a GSM/GPRS module - this has the advantage that you no longer need a third party to tell you where it is from cell id's as they can be sent with the GPS info and you quickly build up a very accurate database. Obvious advantage is that if the GPS fails it’s still pretty easy to find the area your bike is in.

This then ment we had an area so we added Bluetooth so we can then "snipe" for the bike this looks to work pretty well. The blue tooth also allows for data transfer (good for the pits on track days)

So you should be thinking that this thing must be the size of a lunchbox by now but we have managed to get it all in a 54x54x30 box, well we will when the boxes arrive.
By daemondust
velocet wrote:So you should be thinking that this thing must be the size of a lunchbox by now but we have managed to get it all in a 54x54x30 box, well we will when the boxes arrive.
I wouldn't be at all surprised if what jjinno wants would fit in the bike's body below the hole for the seat.
By jjinno
When I first heard the news that the bike had been stolen, my first thought was to get something like an alarm lock and re-develop it to around 200-db. The only problem is that I don't want to have "intent to do harm" charges brought against me, so its probably not a good idea to make the thief go deaf.

Second thought was to electrify the bike with a Taser-like effect, deactivated by a proximity RFID... but again, I think there might be some legal problems with this method too.

Third was the easy one: coat the grips (which would need to be periodically replaced - ok, maybe per use) with super-concentrated Potassium Hydroxide paste, and just place some appropriately sized glassware (think biology test tubes) over the alkali to ride home... and again, I think this would have ME getting arrested instead of the thief.

Finally I decided that it would be nifty (aka - I don't go to jail too) to use GPS, but unfortunately there just is no way of communicating from the module besides some kind of cell solution. I mean wireless is advancing, but nothing is going to give me data-tx/rx at unknown possible distances like cell-phones.

On a quick note, if the module were perfected, you could say bye-bye to the cellphone LCD, and boost battery life significantly. No matter where in the frame you put the device, a discrete power jack would be easy, especially hiding the wiring with any of those LED lamps... for that matter, you could probably use the same battery charger technique, and let the motion of the bike partially recharge the battery.
By dattaway
I had a bike stolen a few years ago. I know how it feels. Fortunately, I got the bike back and became a bit proactive after that. I checked out a few things and tried a few others....

About the best things currently on the market are paging alarms and Lowjack. You might be able to hide these compact devices under the seat with a nice battery. The paging alarms draw about 20mA at 12 volts and run about $140 and up. They have about a 150 yard range and will let you know when the bike is being tampered or has company. Lowjack is about several hundred dollars and a $250 fee when you want it activated for the police to be summoned for locating your bike. The paging alarm system seems easy enough to make out of spare parts...

Here's what not to do... For kicks, I charged the bike with high voltage to see how that would work. I found that concrete conducts quite well around 4,000 volts. With an old laser jet power supply that can supply 70 watts at 8,000 volts, a slight breeze will start blowing ions off the bike. The idle milliamp battery draw would turn into a 5 amp load! Every sharp point would give off a faint blue flame and ozone gas. The kickstand was modified to have a insulated bushing to supply grounding. Unfortunately, the spark was HOT and could ignite things like paper. Not good if you are worried about catching your house on fire when leaves start blowing in the wind. To add a "bang" to the fun, I had a 2uF capacitor. It was an evil experiment. Don't do this. High voltage bad.
By maokh
The protection systems would outweigh the cost of the bicycle. nice idea...but not practical. especially considered the statistical chance of it being stolen again.

But we are all geeks right? who cares.

I would just buy an unactivated prepaid sim off ebay. load it with cash when the bike is stolen. GM862-GPS with GSM antenna, GPS antenna, and Li+ battery. Power generated by bicycle would power the unit's charger.

The GM862 is kinda chunky compared to the frame, but im sure you could come up with something.

On SMS reception, it would upload positioning information. Maybe detect when the SIM is activated, and then send positioning information premptively.


if you are worried about the g/f messing around, you could activate it pre-emptively ;) just kidding!
By velocet
The Idea is sound but the GE-863-GPS would allow for a much smaller package. The other problem with prepaid sims is that if the account is not used for three months then its terminated - read the supplier small print.

If you are really looking to keep things small and cheap hows about using the Aircable SMD bluetooth this has the processing power you need, you could add a GPS reciever via the UART port easy enough.

Ok this only has a 10m range but you could set it up to send a text via any accesable mobile in its range. Offer a reward and your sure to get the text.

I would favour putting the unit in the handle bars rather than the seat making plastic end caps, one for the anntena and the other side for your power jack.
By RR_Security
velocet wrote:So you should be thinking that this thing must be the size of a lunchbox by now but we have managed to get it all in a 54x54x30 box, well we will when the boxes arrive. :oops:
Okay (guessing that you mean millimeters), 2.126 inch X 2.126 inch X 1.181 inch? (Thanks,!)
Excellent! 8)

Okay, some random thoughts from a new guy:
1) If the device you build is too large to fit into the bike frame and still allow access for battery replacement, etc., then maybe hide it in a seat pack. I'd still find a way to make its outer case as tamper proof and "non-removable" as possible, but disguised as something else.
2) "Electronic fence" configuration, where once armed, it will not only tell you where it is, but send an initial alert if it's moved from where she parked it.
3) A mercury or other motion switch could activate it, but might be susceptible to false alarms. A pressure switch under the seat would be less prone to that, but would require the thief to ride it away.
4) An audible alarm is okay if the thief can't silence it (going down the street on something that's screaming "I've been stolen!" is bad form) and for something that you can't get to quickly enough to thwart the theft. A sneaky device that leads the lawdogs to the thief and wins him some time in the Concrete Bed & Breakfast would be my first choice. :twisted:
5) A motion-detecting camera aimed at the usual place the bike is locked up (home) can help gather evidence, even if it doesn't send an alert or help locate the stolen item. Some game/trail/scouting cameras are able to take night photos or video with IR illuminators, and they're not too expensive. Handy for those times when someone apprehended with a stolen bike or other article claims they "just found it."

Good luck with your project.
By RR_Security
velocet wrote:The Idea is sound but the GE-863-GPS would allow for a much smaller package. The other problem with prepaid sims is that if the account is not used for three months then its terminated - read the supplier small print.
How about something in the code to send periodic "status" queries? Does "usage" have to be the SIM originating a call, or merely receiving one? It shouldn't be so often that it chews up the minutes or the battery life, but enough to keep the account active.
(Please bear with me, I just found out today that Python isn't just a big snake or a large Colt revolver, and I haven't had a chance to read all the literature yet.)

I'm also looking for ways to build a locator beacon like jjino asked about, for high-value items without a lot of internal space. I don't want to have to shell out big buck$ for it, or pay a monthly monitoring fee when tracking something by cell and/or laptop would be more efficient.