Fingerprint ID Scanner

This is the place for any magazine-related discussions that don't fit in any of the column discussion boards below.
Post Reply
JPKNHTP
Posts: 488
Joined: Wed Jun 29, 2005 1:01 am
Location: Missouri
Contact:

Fingerprint ID Scanner

Post by JPKNHTP » Fri Jul 01, 2005 7:54 pm

-JPKNHTP
-God Bless

User avatar
Chris Smith
Posts: 4325
Joined: Tue Dec 04, 2001 1:01 am
Location: Bieber Ca.

Re: Fingerprint ID Scanner

Post by Chris Smith » Fri Jul 01, 2005 8:31 pm

The finger print readers work on two basic principals. <p>The first is the optical reader. <p>The second is the soft ware. <p>After gaining a readable scan, the soft ware kicks in and compares a "reasonable comparison" to a known scan. <p>The way it is done varies, but basically it will map several points on a given area, anywhere from five to ten different known “maps” [or areas] of a print looking for curves, over all length of a run, splits, “Y-s” in your print, height, spacings, .....and all sorts of ways "to tell the difference” between one print and another. <p>All of this data is standard by all the law enforcment communities,...., and has been so for over 100 years all the way back to “ink and roll”,...... and to “dust and copy”,....a print from the crime scene.<p>[ July 01, 2005: Message edited by: Chris Smith ]</p>

User avatar
philba
Posts: 2050
Joined: Tue Nov 30, 2004 1:01 am
Location: Seattle
Contact:

Re: Fingerprint ID Scanner

Post by philba » Sat Jul 02, 2005 4:52 pm

I didn't know software was a principal.<p>On cardkeys, the readers are fairly easy to interface to. When you swipe the card next to the reader, it reads the number and transmits it on its interface. What kind of reader do you have? You can get rs232, "clock and data" (mag stripe standard) or weigand interface readers. I'd stick to weigand as the others are more expensive and its pretty common. Look for HID or compatible readers with a wiegand interface. Basically you need 2 lines (plus ground) to read it. Ones are on one line, zeros on another (yeah, its kind of silly but very noise resistant). The number that is transmitted after the swipe is the same as printed on the card. Here's a doc that describes weigand format http://www.hidcorp.com/pdfs/undrstndg_c ... ormats.pdf Note that there is a fairly obvious typo in the doc. You could use a computer or build a little micro to look up the number and apply authorization. <p>what are you looking to do?<p>[ July 02, 2005: Message edited by: philba ]</p>

ezpcb
Posts: 98
Joined: Tue Apr 19, 2005 1:01 am
Contact:

Re: Fingerprint ID Scanner

Post by ezpcb » Sat Jul 02, 2005 6:59 pm

Fujitsu has a finger print sensor. we had developed a module with FPS200, the processor is samsung S3C2410 ARM9 processor. This module can communicating with other uC by UART. have a look at the picture. This is an old version, now the group is developing a new version with Analog Device Blackfin DSP Processor, but I left them.<p>As I remember, Atmel, ST and some other manufacturers have the same product. Reading the image of fingerprint is easy, how to porcess it is the key part of a fingerprint system.<p>Image
http://www.EzPCB.com
High Quality PCB for Electronics Hobbists, Pay for Chrokee, Get Land Rover

rshayes
Posts: 1286
Joined: Tue Mar 04, 2003 1:01 am
Contact:

Re: Fingerprint ID Scanner

Post by rshayes » Sun Jul 03, 2005 7:57 am

Fingerprint sensors can operate in several different ways. The most common methods uase are optical sensors and capacitive sensors. Other methods have also been used, such as thermal conductivity and resistance.<p>The standard resolution is 500 samples per inch. Reasonable images can be formed with a resolution of 250 samples per inch. Constructing a sensor is probably not a hobby project, with the possible exception of an optical sensor based on a purchased camera.<p>Fingerprint sensors have been commercially available for six or seven years, but they are not cheap.

Post Reply

Who is online

Users browsing this forum: No registered users and 37 guests