Page 3 of 3

Re: Defeating electronic padlocks ...

PostPosted: Fri Mar 05, 2010 11:44 am
by HallisChalmers
Would it be safe to assume then, that the lock would have mercury switches that detect pitch and yaw - thus triggering the alarm?

Or perhaps something in the circuit that measures/monitors any change in the capacitance of the circuit?

Re: Defeating electronic padlocks ...

PostPosted: Fri Mar 05, 2010 11:58 am
by elbowmacaroni
Could be, or maybe a steel ball in a small case with leads on the walls like used for the tilt mechanism in pinball machines, or maybe even accelerometers as they are technically just analog sensors, albeit usually the output is run through a DA conversion to be processed by something, but they could be used to just sense movement.

Re: Defeating electronic padlocks ...

PostPosted: Fri Mar 05, 2010 12:27 pm
by eeze
hello every one, only acid and alkaline batteries have a problem when going below zero degrees lithium batteries go at least 50 degrees centigrade below zero, logically there must be some sort of whole for the sound to come out of, also logically it must be a type of piezo buzzer , all you need to do is apply pressure to the diaphragm and that will greatly muffle the sound, years ago car thieves would spray hair mousse into car sirens to muffle the sound so that they could do their deed, simply inject some kind of expanding foam [ polyurethane ] through the vent whole and render it silent, or spray the lock with liquid refrigerant or liquid nitrogen and shatter the lock.

Re: Defeating electronic padlocks ...

PostPosted: Fri Mar 05, 2010 1:33 pm
by loki
I believe the LR44 battery is an classed as an alkaline battery- See Mallory/Duracell specs-more specifically the LR44 utilizes an manganese dioxide chemistry.

If the lock has an orrifice for the sounder, it may be a significant point of weakness in terms of muffeling the sounder.

Lets keep the ideas comming.

Re: Defeating electronic padlocks ...

PostPosted: Fri Mar 05, 2010 3:00 pm
by Magic1
One minute I had never heard of an alarm padlock, but now I find that there are dozens of models and brands out there. I think I have tracked the manufacturer of this one down to a company in China and have emailed them today with some questions.

Yes, out of a dozen different models the sounder hole is usually under the hasp or on the bottom of the lock, I have a load of photos if anyone is interested, but they are all on the web. In either case it would be easy to place a thumb over the sounder hole and I believe it would reduce the noise to effectively ambient. One could of course use chewing gum, but Plasticine or play-dough would work better. If you watched the video, about the only person who would have been alarmed by the lock may have been the person touching it and I think the thief would soon get over that Hi!!. If you listen to the alarm as you move away it sounds like a bird twittering, as it fades into the ambient level. By the way there is a video on youtube of a kid deactivating this lock underwater and that does work well, by deadening the output of the sounder diaphragm. The actual lock has two levels of water proofing and is supposed to be acid proof as well.

As regards to freezing the battery, even CO2 converts to gas at -78 degrees Celsius and my old friend Nitrogen at -210 degree's Celsius. As I said before, CO2 takes longer than nitrogen but does work. I know because I am still here Hi!.

My next thought was with the alarm effectively bypassed, it only leaves the lock to be picked. Does anyone know what key way it is, or is it simply peculiar to the Chinese Kinbar brand ?. Originally I was thinking about a five second opening, but I do not think that is required in practice. It looks good for raking and got me thinking about the linear raking gun again. The design of the rake might be interesting ?.

Re: Defeating electronic padlocks ...

PostPosted: Fri Mar 05, 2010 3:14 pm
by Magic1
"Would it be safe to assume then, that the lock would have mercury switches that detect pitch and yaw - thus triggering the alarm?"

I had a look at prior art, and they seemed to have followed the pendulum trembler path, which left some questions in my mind about lock orientation. Likewise mercury switches tend to be worse and only work at certain angles. A simple modern vibration detector is a small hollow sphere with a ball bearing in it. The inside of the sphere is coated with a piezoelectric material coated with grains of sand. If there is any movement of the sphere in any orientation, the ball rolls into the next 'valley' between the grains of sand ... 'crashing' at the bottom of the space between them and thereby generating an extremely high output voltage from the piezoelectric film ... for a very small movement. In other words ... I don't know Hi!

Re: Defeating electronic padlocks ...

PostPosted: Wed Jun 16, 2010 9:24 pm
by Tecratal
EMP would probably not work since the electronics are encased in the metal of the lock which probably shields it. Acid may work but it would have to be very strong, and plus its waterproof so would take awhile, in the meantime the alarm would probably be triggers, plus acid isn't all that safe. Freezing would probably work but may take awhile, and may be more iffy on weather or not it is truly deactivated, plus what happens once it warms up. I think the opposite may be best. Use a propane or better yet mapp torch on the lock. Solder melts at a rather low temp, plus i doubt the batteries would last long. Submerging the lock in a bucket of water and picking it may be the best way to do it without damage as others have mentioned. It should greatly reduce the sound.

Re: Defeating electronic padlocks ...

PostPosted: Thu Jun 17, 2010 5:13 am
by Phatphish
I have one of these padlocks. Purchased from Aldi stores in the UK. It cost a massive £3.99 which I can say without reservation is about £3.97 too much. The pawl/dog on the end of the cylinder that holds the shackle is tiny and would not take much more than one hit from a medium sized hammer to break. The shackle is only held captive on one side(cylinder side). Once the shackle is removed from the lock body the alarm switches off regardless of the position of the cylinder. Also it is easy to pick and to top it all if you hold the lock with the siren holes in the palm of your hand you can barely hear it sounding. Good fun to pick for a while but a useless padlock in real terms.