First, thanks for reading this. I need to make a "fingerprint reader"
for a security control (start a very expensive machine). but I don't
have idea how I can do this, I have some Laser Diodes from CD-ROM
unit, but I need information how can I read the fingerprint and
compare the data with a personnel database and turn on the machine (I
wish use the 16F84 for control)
>Hi,
>
>First, thanks for reading this. I need to make a "fingerprint reader"
>for a security control (start a very expensive machine). but I don't
>have idea how I can do this, I have some Laser Diodes from CD-ROM
>unit, but I need information how can I read the fingerprint and
>compare the data with a personnel database and turn on the machine (I
>wish use the 16F84 for control)
>
>Really, please help, keep my job depent on that!
>
>Thanks is advance
>
>Sincerely
>
>Cesar E. H. White
These are currently available from at least 2 sources in the states. I
don't have the information right in front of me, as I sent it off to an
agency I work with from time to time. Do a web search, or maybe someone
else remembers it. I think the articles were in ECN or something to that
nature (product promo more than just an article).
Cesar,
I agree with the "good luck on the software" on a PIC. Just to orient and
match a fingerprint requires a lot more horsepower than you will get in any
PIC. Add to that the storage requirements for "valid" fingerprints and you
are way beyond the capabilities of a PIC.
You might consider instead using a card reader (usually RS-232 output which
is easily doable on any PIC) or an RF ID tag reader (again easily
interfaced to a PIC). A previous post today mentioned that Microchip makes
RF ID tags and programmers. Other PIC'ers can probably provide web
references to other ID tag makers or makers of card readers.
>Hi,
>
>First, thanks for reading this. I need to make a "fingerprint reader"
>for a security control (start a very expensive machine). but I don't
>have idea how I can do this, I have some Laser Diodes from CD-ROM
>unit, but I need information how can I read the fingerprint and
>compare the data with a personnel database and turn on the machine (I
>wish use the 16F84 for control)
>
>Really, please help, keep my job depent on that!
>
>Thanks is advance
>
>Sincerely
>
>Cesar E. H. White
SGS Thomson make the sensor, you will need to process this information
though, something designed to use addressable external memory would be
essential here.
>
> Hi,
>
> First, thanks for reading this. I need to make a "fingerprint reader"
> for a security control (start a very expensive machine). but I don't
> have idea how I can do this, I have some Laser Diodes from CD-ROM
> unit, but I need information how can I read the fingerprint and
> compare the data with a personnel database and turn on the machine (I
> wish use the 16F84 for control)
>
> Really, please help, keep my job depent on that!
>
> Thanks is advance
>
> Sincerely
>
> Cesar E. H. White
--
Steam engines may be out of fashion, but when you consider that an
internal combustion engine would require recovery of waste heat by
transfer just before top dead centre then fashion becomes rather
redundant, USE STRATIFIED HEAT EXCHANGERS ! and external combustion.
You heard it first from: Graham Daniel, managing director of Electronic
Product Enhancements.
Phone NZ 04 387 4347, Fax NZ 04 3874348, Cellular NZ 021 954 196.
Hi,
only as an idea:
I am also interested in fingerprint identifying. If I'd do it, I'd store
only the e. g. 32-bit CRC of the fingerprint to be identified. It hashes
pretty good (2^32 is about 4*10^9). As I see, the reader itself is
affordable, however, the SDK is more expensive (abt. $1000) and I am not
sure whether either supports writing own application on not-supported
platforms.
This is my $0.02
Imre
> Cesar,
> I agree with the "good luck on the software" on a PIC. Just to orient and
> match a fingerprint requires a lot more horsepower than you will get in any
> PIC. Add to that the storage requirements for "valid" fingerprints and you
> are way beyond the capabilities of a PIC.
>
> You might consider instead using a card reader (usually RS-232 output which
> is easily doable on any PIC) or an RF ID tag reader (again easily
> interfaced to a PIC). A previous post today mentioned that Microchip makes
> RF ID tags and programmers. Other PIC'ers can probably provide web
> references to other ID tag makers or makers of card readers.
>
> Hope this helps,
> Adam
>
>
>
>
>
> EraseMEpoggespam_OUTTakeThisOuTSHORE.INTERCOM.NET on 02/11/99 08:02:35 PM
>
> Please respond to PICLISTspam_OUTMITVMA.MIT.EDU
>
> To: @spam@PICLISTKILLspamMITVMA.MIT.EDU
> cc: (bcc: Adam Bryant/PEAK/MOORE)
> Subject: Re: Fingerprint "reader"
>
>
>
>
> http://www.digitalpersona.com
> i think they cost 100 dollars for a reader. good luck on the software
> though!
> especialy with a PIC!!
> Regards,
> Ryan
>
> >Hi,
> >
> >First, thanks for reading this. I need to make a "fingerprint reader"
> >for a security control (start a very expensive machine). but I don't
> >have idea how I can do this, I have some Laser Diodes from CD-ROM
> >unit, but I need information how can I read the fingerprint and
> >compare the data with a personnel database and turn on the machine (I
> >wish use the 16F84 for control)
> >
> >Really, please help, keep my job depent on that!
> >
> >Thanks is advance
> >
> >Sincerely
> >
> >Cesar E. H. White
>
>
> only as an idea:
> I am also interested in fingerprint identifying. If I'd do it, I'd store only
> the e. g. 32-bit CRC of the fingerprint to be identified. It hashes pretty goo
d
> (2^32 is about 4*10^9).
Auch! No it doesn't.
Try fingerprinting with CRCs and you'll find a heck of a lot of unknown people
with valid access ;-)
I wrote the following text about six years ago....
[btw, the use of the word 'fingerprint' in that text refers to uniquely
identifing a large set of data by a smaller 'digital fingerprint' - but of cours
e
the same principle applies if you have a human-fingerprint reader. It's a set of
data.....]
Regards, Arjen.
WHEN NOT TO USE CRC
Lately increasingly weird applications of CRCs have popped up, written by
people who don't understand CRCs and their limitations.
The CRC calculated from a block of data is NOT unique; it is highly probable
that a different block of data gives the same CRC value.
Many people respond with "yes, but do look so unique".
They may well look unique to us, but if you need a unique fingerprint to
compare two blocks of data, CRC is NOT the right method.
CRCs can identify certain kinds of bit-errors in a limited length data block,
not distinguish two or more completely different sets of data!
Mis-application of CRCs in this way has caused heaps of trouble in for
instance FidoNet... One program used CRCs to distinguish newsgroup names,
the result was a load of crosslinks. CRCs were also used for detecting
duplicate messages; the result was that good different messages were branded
as duplicates and therefore deleted.
All this was NOT a result of bad implementation, they were just matters
where an algorithm was used for something it wasn't suitable for.
Please don't make the same mistake, the users deserve better.....
For fingerprint purposes I strongly advise using the Message Digest algorithm
(MD4 and now MD5) by Donald Rivest. Specs and sources are freely available.
If you can't find them, contact me.
If you have a FidoNet mailer, you can file-request MD.ARC from my system,
that file contains the original specs for both MD4 and MD5, portable C/C++
sources, and validation/speed-check programs.
BUT WHATEVER YOU DO, DON'T MIS-USE CRCS!!!
On Wed, 17 Feb 1999 15:05:11 +0100 "Arjen G. Lentz" <KILLspamaglKILLspamBITBIKE.COM>
writes:
>"Dr. Imre Bartfai" wrote:
>
>> only as an idea:
>> I am also interested in fingerprint identifying. If I'd do it, I'd
>store only
>> the e. g. 32-bit CRC of the fingerprint to be identified. It hashes
>pretty good
>> (2^32 is about 4*10^9).
>
>Auch! No it doesn't.
>Try fingerprinting with CRCs and you'll find a heck of a lot of
>unknown people
>with valid access ;-)
You'll have much more of a problem of known people with slightly dirty
fingers not getting access. Since changing one bit (or more than 1 but
fewer than N bits, with N depending on the type of CRC) in the source
data is *guaranteed* to chage the CRC, nearly every scan of the same
finger will have a different CRC. It's not a viable way to "simplify"
fingerprint images for storage. The comparison routine needs to be
tolerant of small differences, but certain to reject large ones. CRC is
just the opposite.
I'd tend to agree with John Payson that the chance of different data
having the same CRC is essentially random with the chance depending on
the size of the CRC. CRC generators are like psuedo-random number
generators, with the input data affecting the result. But CRCs tend to
be rather small so the chance of a mis-match is high. True cryptographic
"hash" functions are not so much designed for that purpose as they are
believed to be non-reversible. Given the hashed output, it is extremely
difficult to compute a fake input that will hash to that result.
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TOKYO (AP) - A newly developed computer chip can quickly
identify
fingerprints to help safeguard electronic money cards,
portable
phones and other electronic devices, the chip's creator said
Wednesday. The new chip, developed by Japanese telecom giant
NTT
Corp., takes just 0.5 seconds to match fingerprints with
those
registered in advance with a slight touch on the chip's
surface, the
company said. See http://www.infobeat.com/stories/cgi/story.cgi?id=2558488604-0de
SHORE.INTERCOM.NET on 02/11/99 08:02:35 PM
