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Arduino Forum control 250 doors with arduino
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Related

control 250 doors with arduino

abolfazlnejatian
abolfazlnejatian over 8 years ago

Hey Everyone

 

I have a question about my project and I’ll really appreciate any help you can give,

I’m going to programming a software in order to automatically open up 250 doors with FINGERPRINT SCANNER, I mean I’ve 250 members in a gym and I want to recognize any of them by their fingerprint and then open their related door wardrobe.

So the question is, I don’t know after verifying any individual person and understanding the related door, how can I command to the doors to open?

Let me clarify the sentence, Arduino have 16 pins as output and I’ve 250 doors to control.

I know it’s completely ridiculous to dedicate 250 pins to 250 doors but I don’t know how to overcome to this problem and reduce the pins number!

 

Thank you in advance for your attention to this matter.

 

Many thanks

Abolfazl

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  • beacon_dave
    beacon_dave over 8 years ago +3
    As usual, there are a number of ways to do this type of thing. Perhaps take a look at this tutorial using daisy-chained shift registers: https://www.arduino.cc/en/Tutorial/ShiftOut You could use 5x Arduino…
  • dougw
    dougw over 8 years ago +3
    You can get 256 nodes on an RS485 bus and it can run long distances. It would start with the serial port on your arduino through some RS485 line drivers. http://www.ti.com/lit/an/slla272b/slla272b.pdf…
  • Jan Cumps
    Jan Cumps over 8 years ago +3
    Silly thought: how reliable is a fingerprint recognition system for people who just played basketball, have been swimming or just took a shower after sport? these activities, all common in a gym, alter…
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  • D_Hersey
    D_Hersey over 8 years ago

    If you can open them one-at-a-time, couldn't you use 16 relays to control 256 latches using a row-column scheme?

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  • D_Hersey
    D_Hersey over 8 years ago

    If you can open them one-at-a-time, couldn't you use 16 relays to control 256 latches using a row-column scheme?

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  • abolfazlnejatian
    abolfazlnejatian over 8 years ago in reply to D_Hersey

    Dear Hersey

    Could you explain what you mean by 'using a row-column scheme'?

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  • D_Hersey
    D_Hersey over 8 years ago in reply to abolfazlnejatian

    Sure can try.  256 = 2^8.  Oops, I may have screwed up, I had just gotten up from a nap when I posted last.  We could array our loads as a 16x16 rectangle.  If we took 16 rows and hooked them up to V- through 16 relays, so that 16 loads at a time were hooked up to V- at a time, then we hooked up 16 columns to V+ with another sixteen relays (this is where I screwed up, one needs 32 total relays) we could energize each of the loads randomly by turning on one column relay and one row relay.

     

    https://en.wikipedia.org/wiki/Crossbar_switch

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  • abolfazlnejatian
    abolfazlnejatian over 8 years ago in reply to D_Hersey

    thanks man

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