A sweep frequency generator for lock pick guns etc.

Sweep Frequency.

http://www.youtube.com/watch?v=DzIp6WDLJlA

PWM power control at each step.

OK so far we have 254 frequency steps during a frequency sweep. A lock may fail to open at a given frequency for a large number of reasons and one of them is too much or too little power applied at that frequency. One answer is to electronically sweep through 0 - 100% power at each step, bearing in mind it takes a pick gun a finite time to change speed. I have had to slow this right down with delays, to enable you to see what is happening. The first video shows what is happening on the sweep frequency controllers LCD. The second video shows an oscilloscope view of the varying Pulse width modulation.  At 50% the waveform is high for 50% of the time. At 25% the waveform is high for 25% of the time and therefore the pick gun motor runs slower. At 100% the waveform is high all for the whole cycle and therefore the pick gun motor will run at maximum speed. Varying the pulse width modulation percentage, varies the mean input power to the gun motor.

In practice we would not need 255 steps and a much smaller number could be used. because on a falling or a rising RPM, the motor automatically ramps through all frequencies within the frequency sweep range.

I actually did this last year (I think) but removed all of my lock picking video's at that time because I thought that I had finished with the subject and was also getting complaints from 'locksmiths' that I was giving away their trade secrets !. That was odd because not once had I mentioned drilling locks !. 

I made up the electronic hardware based on a PIC micro-controller and wrote the software to give it the specification above.  The program below indicates that I was ramping the PWM between 0 - 100 % in steps. The idea being to sweep completely through the frequency range, looking for a lock opening. The plan was to add a calibrated weight to the tension tool and detect the movement of the tool at opening and stop the sweep there so the exact frequency could be noted. I was probably thinking of using the linear rake gun for this experiment, driving a bump key, which would over come a lot of problems. 

The idea came from noting that locks often opened during the short period from motor start to less than max RPM and I suspected it was because the natural resonance of the pin pack was low down in this range. The hardware and the software are quite simple, so it would be easy to do this experiment again. 

http://www.youtube.com/watch?v=GyONV_nUJCA

PIC programmed to vary Pulse width between 0 - 100% to set mean power level in sweep frequency pulses. Am thinking of my earlier conclusion that there is no starting point, so open lock 100 times with sweep frequency and note average power level required in pulses. Then repeat with fixed power level and open lock with 100 frequency sweeps and note average spread for that lock. The standard deviation curve should indicate how many spot frequencies and power settings are required to open up the 'general case' lock. Multipick have done something similar but only with frequencies and then come up with spot frequencies for Abus,, Yale etc.. It will be interesting to see if there is any worth in doing this of do locks of a certain brand and make, cover a wide spectrum of characteristics, according to age and wear ?. 

Pin set resonance and pin settling time.

If I want to go on to the 'one strike and it's open', project, I will have to work out an affordable alternative to high speed photography to ascertain pin set resonant frequencies and settling time. Or simply go for it and rely on 'lock opening' for an indicator .... kick ....turn.... no preset torsion, it does or, it doesn't !. So what happens during a rake ?.  Stimulus out of phase, driver pins come down under pressure, strike top of key pins, transfer kinetic energy to key pins which hit end of travel ... bounce ? .... and then follow through with the springs. Wondering why it is so slow ... maybe it is because driven pins acceleration, reduces to zero, before springs return the pins ?. It works with bump keys, but why do the punters delay the torsion in the video's. That is not the point ... the fact is that they do and still trap out all driven pins before the shear line. Key cut comes into this, need the shallowest cut possible to get under the pins .... or can use the delay time somehow ?. How hard and when ????. 

Program for the sweep generator.

Device = 16F877

XTAL = 4

Declare CCP1_PIN PORTC.2

Print At 1, 1, "* PWM Control *"

Print At 2,1, " ",Dec Q, " % "

DelayMS 100

End

To be continued .....