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Re: Chubb combination lock fail

PostPosted: Wed Apr 19, 2017 4:56 pm
by ratlock
I thought Id put a little bit about the microphone ive been playing with to see what others are using. See if improvements can be made.

I started with a 50mm pizo mic from local electrical parts shop (maplin) £1.99, a 1/4 inch jack socket £1.99 a magnet from ebay, and a bit off an old latch for a handle.

The Second Mic I made has turned out better. Instead of glueing the mic straight on to the magnet, I glued a 48mm rubber O ring on first, then glued the mic onto the O ring.

I also ran the cables up through the middle of the magnet, instead of around the outside.

This second version is working much better.

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Re: Chubb combination lock fail

PostPosted: Mon Apr 24, 2017 6:02 pm
by ratlock
Here is an other idea Im going to try out. As well as needing a mic to hear whats going on I need some visual help too.

Here is a £10 microcscope/viewer off ebay that plugs straight into the computer. Its a bit fiddly to get going, but once its focused and set up, its ok for a tenner.

Another problem I had staring at one space in a dial, over and over again, was "is that 4 and a quarter" or "two fifths" or was it bigger last time. After a while i somtimes doubt my own jugement.

I thought id make it a little less subjective, by adding a piece of tipex correction tape on the space between left, and right contact. Then with a fine coloured pen. Mark one line red, and one line green. Green closest together on left, and right contacts.

That way in the first quarter of a space you have black, black/red, red, red/green, green.

I have marked a graph with the colours in the right places too. It helped me be more accurate as I plotted along, less subjective than 4 and a bit. 96 and a bit less.


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Re: Chubb combination lock fail

PostPosted: Mon Apr 24, 2017 9:48 pm
by femurat
ratlock wrote:Another problem I had staring at one space in a dial, over and over again, was "is that 4 and a quarter" or "two fifths" or was it bigger last time. After a while i somtimes doubt my own jugement.


Using colored lines is very creative. A more traditional method is a vernier scale. You have no idea how useful it is until you try it. There's a site that helps you make it http://analoghacking.com/vernier.html

Cheers :)

Re: Chubb combination lock fail

PostPosted: Tue Apr 25, 2017 6:07 am
by ratlock
Thanks very much for the link Femurat. Tried to open the program, and antivirus software says there is a virus in the program, and wont let me open it.

Re: Chubb combination lock fail

PostPosted: Tue Apr 25, 2017 7:01 am
by femurat
I have it on the office pc and never had a problem. Now my isp is marking the website as potentially harmful. Maybe they don't like the word hack in the url.
Tell me size and numbers of the dials you have and I'll send you a pdf tomorrow.

Cheers :)

Re: Chubb combination lock fail

PostPosted: Tue Apr 25, 2017 12:32 pm
by MartinHewitt
ratlock wrote:Here is an other idea Im going to try out. As well as needing a mic to hear whats going on I need some visual help too.

Here is a £10 microcscope/viewer off ebay that plugs straight into the computer. Its a bit fiddly to get going, but once its focused and set up, its ok for a tenner.

You really are a toolman!

Re: Chubb combination lock fail

PostPosted: Thu Apr 27, 2017 5:34 pm
by ratlock
Ive been having a play with things that make things easier for me to use, when manipulating wheel locks.
This little gizmo I can really reccomend. The Vox Amplug.

I bought 2 second hand off ebay. One Bass, and one metal. The guys out there who know more than me about the musical merits of both, will know more about them.

I tried both, and the metal one really is the cats whiskers when listening to every tiny movement.

Although its a contact mic, and as such should only hear direct sound waves through contact. I could even hear myself breathing.

If your going to make your own contact mic, I would reccomend trying a small Vox amplug.

It runs off 2 AAA battries, and your normal headphones plug straight in.

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Re: Chubb combination lock fail

PostPosted: Fri Apr 28, 2017 3:02 pm
by Jaakko Fagerlund
Can that amp filter out what you want? In safe work the most useful filter is a high-pass filter, as then you don't hear any footsteps from the next floor, only the high pitched "clings and dings" from the locks metal components hitting each other. I have had trouvble finding a cheap amplifier that can do this, most places just like to rip you off like there is no tomorrow.

Re: Chubb combination lock fail

PostPosted: Fri Apr 28, 2017 6:55 pm
by ratlock
Im not sure how this would compare with the one your thinking of with the high pass filter. This youtube clip might help.

https://www.youtube.com/watch?v=UVBDHSINSxQ

Up until now I have tried an off the shelf "listening" device ive seen rebranded and sold online as a safe listening device. I bought mine on Ebay. This wasnt very good.

I made my own prototypes piazo mics, some good some not so. I tried a couple of guitar practice amps, they worked good, but I wanted smaller more portable, and low power useage. These use 2 AAA battries, and can be bought for £20 ish second hand off ebay. So not a lot of money.
They work good, very light and portable, and they are designed for a quality sound reproduction, for serious musical practice.

The only other modification Im intending to make to this set up for now, was suggested to me by Capt Dunk.

His idea is to put an in line push button to contact switch. So you dont get all the crunching, and grinding background noises you dont want. Just push the button when your ready, and listen at the critical moment.

This is a good idea that I will make soon.

The Mic im running into this is very sensitive, which may be great if its stuck to a metal door, but if it falls off your lap when your practicing dialing in the van waiting for the kids, it almost bursts your ears.

Re: Chubb combination lock fail

PostPosted: Sun Apr 30, 2017 9:19 am
by ratlock
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Here is what I mean by an in line switch. Push button to make or break contact. Which ever you prefer.

Re: Chubb combination lock fail

PostPosted: Wed May 17, 2017 4:58 am
by Oldfast
ratlock wrote:Heres that last lock finally mounted up on 10mm plate. Its a big lock to mount up.
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Holy magnificence! That's beautiful. Wonderful mounting job. Love it!!!

Re: Chubb combination lock fail

PostPosted: Wed May 17, 2017 12:22 pm
by ratlock
Thanks Oldfast, it spins pretty good too, for a big lock.