how the Xena disc alarm actually works


xorbe

Member
The lock and the alarm are independent. The alarm doesn't know if the lock is engaged or not.

The part in the instructions about locking and unlocking a couple times "to wake the alarm up from sleep mode" has nothing to do with locking and unlocking, and everything to do with simply jiggling the alarm. So, the alarm doesn't sleep if it's riding along in the back of the bike.

The alarm sends an IR pulse that bounces to an IR receiver. If the pulse is seen, the alarm assumes the lock is not closed. If the pulse is blocked by the disc, then the alarm assumes the lock is installed.

I'm pretty sure it would be trivial to use a thin piece of specially shaped clear plastic that would route the IR pulse from the emitter to the receiver, and disable the alarm. Also, there is no beep to indicate the alarm disarmed. The only way to make sure it's staying armed is to go bump it some time later, etc.

Time from warning beeps to full-alarm isn't really enough to get the fiddly key in there, and the lock off the disc: 5 seconds.

Because the pulse cannot be reflected to the IR receiver while installing the battery, you'll have to wear earplugs to get it assembled.

I hadn't seen this level of detail posted. Thought someone else might like to know.
 
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