You can’t always keep your eyes on your bike, but the RFID Bikealarm is the next best thing to having someone watch your bike. Designed by Dennis Siegal, this device attaches to a bike saddle and emits a 120dB alarm when moved. This isn’t meant to replace a physical lock but rather to provide a low-cost second line of defense.
The alarm is activated by holding an RFID tag close to the device until an audio acknowledgement is sounded, and deactivated the same way when the owner returns. Siegel opted to use RFID technology as opposed to Bluetooth as a way to keep the costs down. Siegal designed the RFID Bikealarm as part of his university studies at University of the Arts Bremen in Germany.