logic of scrambled keypad!!

Go To Last Post
16 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Hi everyone,
can any one help me in the logic of scrambled keypad??
any thing useful like codes or documents :?

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Would you be so kind me lady to provide us with a schematic, part number or anything else you might have?

Little difficult to help with so little information.

Jim

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I wonder if the below is what "lady" is speaking of? As Jim mentions though, we are left guessing at what you really want.

http://securitymanagementsystem....

(second hit in Google, this thread was the first hit :-) )

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Hi again,
Scramble keypad provides a very high security approach to access, because the PIN number cannot be accidentally shared with, or stolen by, onlookers. Each numeral is randomly scrambled to a new position each time the START button is pressed, so a bystander cannot see the code, learn the pattern, nor identify telltale wear marks on certain keys. Also, viewing restrictors allow only the person directly in front of the keypad to see the numbers, eliminating “shoulder-surfing.
So my question is, is there any one know how the scrambled keypad work or the logic( way of doing the scrambled in the keypad)???

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I'd guess if such a method was used, it would RANDOMLY shuffle the keys around on a touchscreen? A somewhat simple operation... if you have a PC at your disposal.

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Yes, I agree with you on RANDOMLY shuffle the keys around on a touch screen.
But I want more details and help on writing small program to do something like that (scrambled keypad)
And this site to help you to understand what I mean.

http://www.hirschelectronics.com...

[img][/img][img][/img]

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

You're looking to do quite a lot here, particularly on the hardware front: the example above suggests seven segment displays in the switches, but you might use active LCD switches (with tiny LCD screens on their tops) or a touch sensitive screen where an image of the keypad appears.

That's probably the most complex part of the program - hardware and software - and until you can get a static keypad working there's not a lot of point going further.

However, to move the keys around, you can use a routine similar to shuffling a deck of cards: fill an array[10] in order with the values 0-9; these will be the value your key returns. Generate two random numbers between 0 and 9 and swap the contents of the array at these offsets. Repeat as required - twenty or thirty swaps will probably give you a pretty good shuffle but test it.

This of course depends on the randomness of your random number generator - try seeding it with time of day, or time since the last key was pressed...

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Wow, my SWAG was spot on :-)

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Thanks barnacle for these information. :)
I need your help plz to know how can i call the function that generat rundom number but form the computer timer not form range of numbers that we choose.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Just let a timer run. Read it when you need a new value. That is reasonably close to a "random" number. However, you will have to figure out how to map the 8 or 16 bit value into key numbers, especially since a hex value can give something outside of the range of 0-9 AND you can get duplicates.

What might make more sense is (for example) a set of 16 tables, each table providing a different mapping than all the other tables. Then use 4 bits of the timer value to select the table to use. This can be extended to any arbitrary larger set of tables.

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

To generate pseudo-random numbers good enough for your application: http://farside.ph.utexas.edu/tea...

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Did anyone else hear "Please do my work"? Anyway, google is your friend. And as for the random generator, C uses the rand() function. Google it for more info,

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

daqq wrote:
Did anyone else hear "Please do my work"? Anyway, google is your friend. And as for the random generator, C uses the rand() function. Google it for more info,

I guess to some, AVRFreaks is simply a "Means to an end. "

They're getting easier to spot, and I find myself ignoring more of them each day.

It's sad, though...

The "Taker " usually comes here hoping to take information that will provide him/her with a passing grade.

The real learner will come here with knots on his/her head in attempts at solving their own problems first.

The sad part is, if the two were side by side in an opportunity to secure a good (read fun) job, the slacker would be the one to get that job.

It reminds me of a time back in the early 1970's when I was applying for a job in Claremore Oklahoma. While I was waiting for the pending interview, another interviewee showed up. It was a sad thing, because this guy couldn't read or write. Feeling sorry for the guy, I filled out his application. The real pisser is that, he got the job. I think I shared this before. But that is the way the system seems to work.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

HI there, i just saw the site (http://www.hirschelectronics.com...)
The random number produced each time the start button was pressed. Yeah, it looks like random but hey, we can use ordinary timer/counter to setup the number. Eg: set the timer to run always at anytime then display the value when "start" button was pressed. The randomness depends on user's finger pressing. see what i mean? I was use this method to make a simple electronic dice.
Don't bother to use such calculus thing if we can use simple method one :D

KISS - Keep It Simple Stupid!

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Hii,,
Thanks guys for ur help :D
these information very useful to my project.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Steve wrote:

Quote:
Wow, my SWAG was spot on Smile

I, for one, was impressed!!

John

Just some guy