Alarmed bike chain, sounded by broken circuit

[wjc132]

I am currently undertaking a design project, encompassing a bike lock where if the chain is broken an alarm will sound. My initial thoughts are to use an existing personal alarm (the cheap ones with a rip cord) and attaching a circuit through the chain. When the chain is cut the circuit is cut sounding the alarm. I am a novice in electronics and was looking for some general advice concerning what is involved with the electronic component i.e. is it feasible to connect a circuit (wire) to the personal alarm and if this alarm is cut making the alarm sound? Any feedback or reference to helpful material would be very welcome!! Thank you

 

[kchriste]

This will be easier to do with a cable lock than a chain lock. You would need an electrical break in the loop, probably at the lock, for it to work. Yes, using an existing personal alarm would simplify it a bit.

 

[wjc132]

Sorry, yes to clarify I would be using a cable lock

 

[yngndrw]

If you want to be lazy, you could run a thin cable along with the lock cable. Put a connector on the end so you can detach it to remove your bike.

If the lock cable is cut, the theif would still need to cut / break / disconnect the alarm cable in order to release the bike.