RFID Bikealarm scares off would-be bike thieves


February 17, 2014

The RFID Bikealarm attaches to a saddle and emits a 120 dB alarm sound when it detects movement

The RFID Bikealarm attaches to a saddle and emits a 120 dB alarm sound when it detects movement

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Very little beats a sturdy U-lock for securing a bike. For when there's nothing available to which you can secure your bike, however, or if you just want a little extra security against anyone tampering with it, designer Dennis Siegel has devised a solution. The RFID Bikealarm attaches to your saddle and emits a 120dB alarm when it senses movement.

"The RFID Bikealarm is meant to be a useful add-on to mechanical bicycle locks because it massively extends the range of protection with only a few components," Siegel explains on his website. "It is low-cost, durable and easy to use."

The Bikealarm was designed as part of Siegel's Bachelor degree thesis at the University of the Arts Bremen in Germany. The final outcome is a prototype that aims to spook any would-be thieves the moment they begin to interfere with the bike to which it is attached. The device is able to distinguish between ambient vibrations or fluctuations and more focused movement.

"I used a micro-power omni-directional vibration sensor that is connected to a microcontroller," Siegel tells Gizmag. "It continuously senses the environment to distinguish between specific events, for instance a passing tram and a serious theft."

Siegel created a working model of an alarm that would sound when it sensed movement, but wasn't initially sure how it would be best attached to a bike. "I decided to mount it to the rails of the bike saddle because it allows for comfortable interaction and the position is less conspicuous as it looks like a small repair kit," he says.

Siegel opted to use RFID technology rather than Bluetooth to keep the costs down. The alarm is activated by holding an RFID tag close to the device until an audio acknowledgement is sounded. Likewise, the device can be switched off using the same method when the user returns to their bike. Siegel explains that the most difficult aspect of creating the alarm was to get the electronic circuit down to a small enough size.

The prototype runs off an internal lipoly battery that can be charged by USB within 2 hours and lasts for a few days with normal use. As the device is only at development stage, this could change should it be rolled out commercially. But, according to Siegel, there are no agreements in place to do so as yet.

The video below shows a demonstration of the RFID Bikealarm in use.

Source: Dennis Siegel

About the Author
Stu Robarts Stu is a tech writer based in Liverpool, UK. He has previously worked on global digital estate management at Amaze and headed up digital strategy for FACT (Foundation for Art and Creative Technology). He likes cups of tea, bacon sandwiches and RSS feeds. All articles by Stu Robarts

What a great idea! An even better one would be including a wheel-mounted charger, so that riding the bike would recharge the device.

Joel Detrow

Actually, most U-locks are physically sturdy but use cheap POS locks. There are exceptions but you pay dearly for them. They also weigh about 5 pounds.

Anne Ominous

I suspect that people would very quickly get tired of the false alarms and just ignore the alarm, unless Siegel is somehow smarter than all the engineers at the companies that make annoying car alarms. Sometimes, I wish there really was a thief just so the stupid car would be stolen and I wouldn't have to hear the alarm anymore.


That's just what all the inner cities of the world need… lots more noise! Can you imagine what would happen in China if this took off? It's a bloody silly idea. Realistically, where are you never going to be able to find something to lock your bike too? The middle of a desert and in the middle of the sea. Neither should prove too serious an issue. MW

Martin Winlow

It could never suffice on its own. It would have to be in addition to a bike lock. Otherwise the thief could just quickly ride off to a less conspicuous place and smack at the lock with a heavy object.

The more expensive the bike, the better the lock should be. I ride a so-so bike for errands around town, and my good bike is used for exercising and rarely gets left/locked anywhere. I'm speaking as someone who's had a number of bikes stolen (in a big city).

Always park the bike in a visible area, and use a good quality Ulock that can lock the frame AND a wheel to something immovable.


It will suffer from the same problem all bike alarms suffer from, its on 24-7 and it eats batteries. When the battery goes dead its useless and when its inside charging, its not protecting anything. The fact that it has to go inside to charge presents the other problem all bike alarms suffer from, if its easy to remove its useless. If its easy to get to the power source it will be disabled. And then the third problem with all alarms, bike or otherwise, if it is easy to trigger and goes off a lot, people will not only ignore it, they will be mad at you for subjecting them to this annoyance.

Billie Matteo

I think this device/idea has a lot of potential. More than just a bicycle theft deterrent, it could be attached to any sporting goods item or personal property that might have cause to up and walk away: small boat, canoe, lawn mower, large construction tools, camping gear, camera tripod, equipment bag, etc. Of course, the owner of the property should take as strong a method as is practical to prevent theft. Nothing will stop most thieves who are determined. This device adds a first level deterrent. I would buy several today.

Fred Key

it says low-cost Well how much $ and where?


silly it has to be recharged every few days? if seat has a quick release you could just remove and ditch the alarming seat

why not just invest in a good lock?

where is there ''not anywhere to lock your bike'' ? which is also so theft prone that you need this thing and un-isolated so someone would notice the alarm and where anyone would care..?

what protects the bike while the dumb alarm is charging?


Larry English

I like the idea......BUT.......

I'd want to know if anything has happened such as the alarm going off. These days with the internet of things, there must be freely accessible development tool to help this. The way I would envisage this would be:

1) RFID activated 2) Motion detector detects movement 3) Siren kicks out its dB's. 4) Alarm connects to local free or approved WiFi and sends a notification to my phone or network where I can pick it up through tweets, emails, texts etc. 5) I know that the alarm triggered at what time, and/or I can go and check if it is still there.

Services such as IfThisThenThat can help connect this very easily, all the alarm has to do is have an output to the net.


Dr_Stav; you miss the point of the design when you ask for internet connectivity- so far, it's designed to be a cheap, reliable, small device. It's nothing but a small extra on top of the normal bike locking (that so many people don't do properly). I have two suggestions to streamline the idea. First: Integrate it in a battery backlight with easy-to-change battery access. Second: Design it as an attachment to (any) U-Lock.

Leo Leiski

Gives me an idea for a art project to combine DRM and bicycles after seeing The DRM chair.

Michael Klegin

My son had a seat and a tire stolen from his bike with THREE LOCKS on it. College campuses suck! Looking for something that will make a lot of noise if anyone touches his bike. Anyone know anything, send me a message on FB.

Nanci Zee
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