As for overseas bicycle thief, there are lots who used electric power tools at a high traffic place and stole handreds bicycles. Some of them became to be famous and I had known that.

A certain media in NewYork City tried an experiment how did people react to someone who was breaking a lock of a bicycle at the Central Park in broad daylight due to own prepared bicycle locked preliminarily.
As results, there was no reaction nor report, except one person who advised that there was more convenience tools which should be used.

In Japan, many people have told that recent bicycle thiefs are intrepidity. They use not only electric power tools but also a cargo truck with a crane.
However, there's different to overseas at a point that high theft area is out of the way in Japan. e.g. bicycle parking located sit back.
I don't know whether it's the mind of the theft or a high-traffic which refuse theft due to report or something reaction.

I would write my actual experience as follows which made me fully aware that it's difficult to steal a bicycle at a high traffic place. No, Don't get any wrong ideas, I never try to steal.



As for a right picture, it's an end up of the u-shaped lock which is a same one of the picture at top of page. The cylinder of the lock was broken and I had nothing except to cut it.
I parked a bicycle at a high-traffic place in city. After I tried to unlock I found the key never turn. The cylinder fixed the u-shaped bar at two points. One of them was came free but another was not.
With this, there was nothing except to cut.

I don't bother to write what I used, how long it took, about Qs and As to the police.

I guessed to cut it expeditiously though the alminum bar filled on inside took decent time for cut. Of course I became curious about public attention. But I had not done something wrong. It all began with the faulty lock.
And I tried to devote to cut though...

The police had come as soon as I began to cut.

The police questioning. With that, I felt better cause I could submit to a police questioning and explained circumstances and which could be heard by.
The policeman heard my explanation and left away by saying with a laugh that he wondered I was going to cut the guard rail.

I started again to cut it though, another policeman had come.

What is it all about? I explained once again. The policaman was gruff and left with saying okay simply.

After a short time, I notice a car with red lamp on its roof which parked at a distant about fifty meters. And third police questioning.
I had the luxury for third times. It's terrible to get accustomed to.

Among the third police questioning, the first policeman came again and called forward the third policeman, whispered something. And they all left away with sketch a wave as goodbye. The matter seemed to be a topic in their communication linkage in guessing.

The only condition which made these questionings possible was that there were multi reports.

Over such a matter, which was a false accusation though, I took my hat to their movements. I knew as much about public security could work out by the police.
And I took my hat to people who reported too. That's a false accusation though I cannot but appriciate to them.



A burglar alarm has a powerful effect. That depends on the national background in this case though, the security could be got in association with. Cause there is nothing else at last.
Besides as for a bicycle thief he is striked into leave by the alarm.

However there are some problems more I think about it.


Those right and wrong are depends on the place. The question is in city with a high traffic place as premises. What is proper specification?

That's a difficult decision as considering various likelihoods.
It's impossible to continue to alarm after impact at a high traffic place cause the impact might be due to a passing passenger. A bicycle parked in city is already thought as disturbing. However it could be alarm continuously during the theif is handling. And the switch should be key-lock one, it could be alarm due to try to open the shell, and so on.

After thinking, --


At first tried to make



As for a blocking oscillator, it's diverted from a cheap security alarm. I forgot to write 'R' for VR connected in series though please think there is an R as common sense.

There are parts for control and oscillator, speaker, LED for check which are selected by a three positioning key-lock switch.

Its standby power requirement is almost none. It's no problem to use a button battery though it sounds a loud alarm. Its loudness doesn't depend on battery boltage but on a shell as an enclosure.



Test of a control unit.

Test of a oscllator for alarm.


on a breadboard.


test for a LED for check.
the LED has same condition to turn on

test various sensors



As for a left picture, there is the mercury switch which is already disconstruction cause it has environmental toxins.



Tentatively, tried to fabricate parts.
with some aerial wired.


It's concerned to be small.



A shell is small, width 35mm height 25mm depth 50mm, and tough due to fleshy ABS resin though inner space is very small.

hardly succeed to install.


It's easy to additional strength cause filled innner space.

under view.


compact and high performance in guessing.





overhead view.
It's better to be in shade.





high density.


It's a VR colored aqua with a yellow circle which could adjust time of continuous alarm around 1.0 ~ 15 seconds.
That's enough length in guessing, As I have an intention to use it due to 7 ~ 10 seconds.


Of course the bike would be handled continuously it could continue to alarm.



Around steering is desired to be clear.
There is tendensy to make that pell-mell since the ahead stem. At least on my basis there are enough a head lamp and a cycle computer only.
If the security alarm had set on other place it would be difficult to adjust a parking angle for sensibility. Practically it adjusted at once is used without exchange though it wouldn't be located within close reach.

As definitive dissatisfied point, it's bother to adjust the sensor for vibration and gradient.
I wish to exchange it to simple vibration detector. For practical use a simple vibration detector is better cause it's no need to care parking angle.

With that, I had not used it.

Something attached to a body would made me to be dissatisfied, I made a security alarm attached to a wire which would alarm due to be cut.

Specifications as follows.


It would alarm against to a malevolent intention.
Standby warning flash is a standard tactic for security which is expected to make thief to take care.



I have not drawn the circuit diagram yet. In the time, ... ( I'd already uploaded the exact diagram at a next chaptor )

That is consisted with three parts.
It would alarm due to try to open the shell, e.g. to ease the bolt.

-- I mistaked to draw battery as two cells though it's one cell correctly. in the time I shall draw the circuit diagram as discrete.



Test on a breadboard.
Test by a core part.

The current was uA level for standby. It could be used several years due to CR2.


Its design was took from the initial security alarm attached to a handle.
Two bolts are used to fix the cover at both sides which screw into a long screw nut fixed inside. It would alarm due to ease the bolt.

Finished due to bond and additional strength.

The u-shaped lock could lock a bicycle frame and a street funiture, and it consolidates the security to hook the loop of wire to the bar of u-shaped lock, and to reeve the wire to both front and rear wheels, frame, guard rail, which would prevent the bicycle stolen without cutting the wire.



I tried it to alarm at side of arterial road with high traffic noise on purpose.
It sounded very loud indoor which was bad for the heart though, I worried how loud it sounded at noisy place. And I found that the alarm attracted public attention cause the quality was peculiar. I was really shamed for that even if in a short time.

I have been using it as usual which has given me a feeling of security.
It's not hassle to carry as same as just a wire, it doesn't bother to turn on the lock, the warning lamp is intermittent. I think it's very right and usefull.

Of course the wire could be cut easy by a hand tool. The u-shaped lock also could be cut by an electric power tool. Such a security alarm might be broken momentary by thieves which has lots of tools.

I had an intention to exchange the battery, unbolt, uncap, and tinkered with and broke it...
With that re-creation.

I noticed that I made it seven years ago and the CR2 battery had been kept well. I amazed that though, it worked just to flash lighting intermittently during standby. That sounds about right?



I drew its circuit diagram which is actual one.

The IC drawn at lower right in the diagram is diverted from a cheap security alarm.
The lines of relaxation oscillator and warning lamp which should be connected to GND, connected to a trigger pin of the IC. That might be wrong method though, It's going to work well and so it might be no problem...

There is a different point compared to previous one, it sounds due to boost voltage by the HT7750. But it's not so larger to sound loud.




Parts

Test on a breadboard due to fabricate a unit.










fabricated

A UEW is used cause small space, wrapping wire was used for an initial one though.









Finished



It's really convenient.
With that, "Vibration Detection Security Alarm" is left derelict on a breadboard.

I think the warning lamp has large effect which gives me a feeling of security and might be suspicious for the thief.

I have an intention not to decorate items to the bike and definitively I would make it as hidden trick, that's why inmount to inner space of a saddle.
Specifications as follows.


Its scheme is almost same as initial security alarm "Vibration and Gradient Detection Security Alarm".
As for different points, attached place, loudness, battery in common used, and the sensor.
The sensor is exchanged to the piezo.
The piezo sensor generates slight electric power which would be used to switching.