Project: Biometric Projects (a sort of complete how-to)

Discussion in 'The Completed Projects Collection' started by kyroguy, Oct 5, 2010.

  1. kyroguy

    Thread Starter Member

    May 12, 2010
    77
    0
    Biometric (fingerprint reading) projects seem to be getting more and more popular these days and with biometric readers turning up on everything from laptops to door lock just about everyone has seen them. When I first saw a biometric pistol safe I thought it was absolutely awesome, but it was also absolutely out of my price range. (~$300) Well, if you can't afford it, then you have to build it or go without...and I don't like going without.

    So I knew what I needed, a fingerprint reader and a safe. Of course the knowledge to put them together was the hard part!

    I happened to be browsing clearance items at the mall one day and ran across a Craftsman Fingerprint Keyless Entry Pad for a garage door. (Sears item #53555) Thinking that these might work for my pistol safe project I bought them all. (They have been discontinued by Sears, search eBay for "Craftsman Fingerprint" $20-$50) So I had the biometric half of the project, now I needed a safe.

    I searched for months and finally found a counter top pistol safe with a broken key pad which I picked up for $20 including shipping. Here was the other half of the project!

    I retreated to my workshop to mate the two. I poked around for days on the fingerprint readers circuit board trying to find a suitable place to take a signal from to trigger the safes latch (to open the safe door). I finally found a tiny pin on a tiny IC that was giving me the signal I needed. Should have been a simple matter to take the pulse and use it to open the door. Only problem was that it also gave a very short pulse when the circuit was first powered on. I had to build a circuit to tell the difference between the "power on pulse" and the "proper fingerprint swiped pulse".

    Having no formal electronics education I turned to these forums and began asking questions. (see the original thread here) "eblc1388" came to my rescue and helped me build the circuit I needed. Here is how it happened.

    [​IMG]

    Here is what you will see when you first open up the fingerprint reader. You will need to flip the circuit board over.

    [​IMG]

    The red arrows indicate the pin and associated pad from which the "proper print swiped pulse" can be taken from. I used a very thin insulated wire and threaded it up and down through a few of the holes surrounding the IC so that if the wire was tugged during reassembly the solder joint wouldn't be strained.

    [​IMG]

    Here is the circuit that "eblc1388" designed for my project. It is based around a CD40106B. The "6v" marks indicate connection to the 4 AA batteries that are inside the fingerprint reader. This circuit runs off the same batteries as the reader. The "12v" mark indicates a separate battery pack that is only used to run the door latch. I understand that eblc1388 will be selling a limited number of signed prints of this artwork. Freehanding schematics is not easy! ;)

    [​IMG]

    Here is the final product. I have purposely been a bit vague on the exact details of this particular build to protect the security of my project. I want the moral of this story to be that you can use the same fingerprint reader and circuit described here to add a biometric aspect to any project you have in mind, not necessarily to highlight this specific project. I think with the descriptions, item numbers and schematic provided here that you will be able to fill in the details. :cool:

    I estimate that the circuit cost about another $15 to build including a few parts that I bought and didn't need. That brings the total cost of this project to between $55-$75 (approximately). If you have any of the parts laying around it could be quite a bit less. That's great compared to over $300 for the commercial unit!

    If you want to browse the (extremely) similar write-up I did on my website you can find it here. If you want to check out other random stuff, especially saltwater fish related stuff you can see my homepage here.

    Here is the safe in operation on youtube!

    I hope this post helps someone as much as eblc1388 helped me. Props to him!!!!!
     
    Last edited by a moderator: Dec 27, 2011
  2. kyroguy

    Thread Starter Member

    May 12, 2010
    77
    0
    My project made HackADay.com!

    [​IMG]

    See the whole thing here.
     
  3. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    Congrats on following it to through.
     
  4. eblc1388

    Senior Member

    Nov 28, 2008
    1,542
    102
    Nicely done Kyroguy.

    I visited your homepage site and noted how you have killed something using lemon juice. :)

    The tear down of the Pillcam is interesting too.

    L.Chung
     
  5. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,699
    907
    I think it is a great project and beautiful hack.

    I do wonder how secure the fingerprint reader is, both false goes and no's. Tried to find user evaluations for the reader, but couldn't. So, I just bought one. Still <$25 (new) for some fun isn't bad.

    John
     
  6. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,699
    907
    Update: Bought and received the fingerprint reader. I think I know why it has been discontinued. It does work, on occasion. But my old, dried, and scarred fingers require multiple tries before getting a pass. That is certainly not something I would want to do outside at night in a freezing blizzard. A numeric code is simpler, but clearly not as fun.

    Nevertheless, it is still a great project for tinkerers. John

    Edit: Been playing with it some more. Switched fingers and found my middle finger (fewer scars and cracks) works better. Enrolled multiple different users for the same finger. It may decrease security a little, but it improves recognition with a single swipe.
     
    Last edited: Oct 10, 2010
  7. kyroguy

    Thread Starter Member

    May 12, 2010
    77
    0
    My fingers haven't had any problems being recognized by the reader. There is the occasional miss but it is usually when I am swiping sloppily. The only other problem I have had is that if I have just applied lotion to my hands I have to rub the finger vigorously on my pants to clear the lotion from the print before swiping.

    I am super happy with this project. I use it daily. Thanks again to all who helped!
     
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