Electronic Bicycle Lock


The electronic bicycle lock designed here is a worthwhile alternative for bicycle owners who want to make their bicycles ‘intelligent’ at reasonable cost. One of the benefits of building it is that the circuit can be used for virtually any make of bicycles. In the circuit, two standard RCA sockets are used as input jacks. A home-made security loop can be used to link these two input points. Around

50cm long, standard 14/36 flexible wire with one RCA plug per end is enough for the security loop. It is powered by a compact 9V battery (6F22). Key lock switch S1 and smoothing capacitor C2 are used for connecting the power supply. A connected loop cannot activate IC1 and therefore the speaker does not sound. When the loop is broken, zener diode ZD1 (3.1V) receives operating power supply to enable tone generator UM3561. This tone generator remains enabled until power to the circuit is turned off using switch or the loop is re-plugged through J1.

Assemble the circuit on a general purpose PCB and house in small tinplate enclosure. Fit the system key lock switch (S1) on the front side of the enclosure as shown in Fig. 2. Place RCA sockets (J1 and J2) at appropriate positions. The finished unit can be mounted in place of existing lock by using suitable clamps and screws.

block diagram



  1. Highly sensitive
  2. Fit and Forget system
  3. Low cost
  4. Simple and Reliable circuit


  1. Movable Assets
  2. Bicycles
  3. Two Wheelers


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One Response to “Electronic Bicycle Lock”

  1. portable generator reviews says:

    Thanks for any other excellent article. Where else could anyone get that kind of information in such a perfect manner of writing? I have a presentation next week, and I’m on the look for such information.

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