laser data transmitter and receiver

Discussion in 'The Projects Forum' started by jm0825, May 28, 2010.

  1. jm0825

    Thread Starter New Member

    Nov 9, 2009
    6
    0
    I have built a laser data transmitter and receiver for my final project.
    The Instructor wants to select the bits manually and to send them across the room to the receiver. The problem I am having is that the receiving SI/PO IC is not latching the data and keeping the LEDs lit. I am using a One shot on both sides to send 8 clock pulses the receiving end receives the first bit to start the clock the second bit goes to the SI/PO. Currently it blinks and everything is gone. I have adjusted the clocks so they are exactly the same.
    Thanks for any suggestions or help in advance.

    P.S. I have already presented this and the instructor was happy that I was able to send data. So the grading is already done. I just want it to work right before I tear down my protoboards

    Heres the schematics

    [​IMG]
    [​IMG]
     
    Last edited: May 28, 2010
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    The arrangement of voltages to the DIP switch insures that the 'HC165 always see those inputs as HIGH. Use the DIP resistors to pull up the input lines, so the DIP switch can connect to ground.
     
  3. jm0825

    Thread Starter New Member

    Nov 9, 2009
    6
    0
    Sorry, I had the parallel in lines touching the VCC line on the SIP in the schematic. I have corrected this error.

    I need some clarification please. I thought if I used a SIP network pin one going to VCC that they would see a HIGH until the DIP switch was turned on then it would see ground. If this is not the correct way how would I wire it?

    Thanks
    Jack
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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    The connection for the data lines has to be on the side of the pullups away from the connection to Vcc. That is, between the resistors and the DIP switches. When a switch is open, the line is pulled up through the resistor. When the switch is closed the line is tied to ground, and the resistor isolates the Vcc voltage so it does not get shorted.
     
  5. jm0825

    Thread Starter New Member

    Nov 9, 2009
    6
    0
    Figure B is what I am understanding that your saying about using the pullup resistors. Figure A is what I have on my breadboard. They are the same are they not? or I am I totaly missing this?

    Thanks
    Jack

    [​IMG]
     
  6. beenthere

    Retired Moderator

    Apr 20, 2004
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    Figure B will work correctly. In the A circuit, the switches are invisible to the IC.
     
  7. jm0825

    Thread Starter New Member

    Nov 9, 2009
    6
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    I checked with my DMM when the switch is on it goes to 0V when the switch is off I get 5V presented to the IC. Picture A (which is how I have it set) is as it is on the breadboard, picture B is the schematic.

    I not very good at drawing in 3d but the SIP is standing the resistors up vertically, I drew it laying down flat so it is easier to read.
    The bus along that line on the breadboard is connecting all the pins together.

    I have the same setup on the receiver to ground the LED bar.

    I like the usig the SIP network on the protoboard because you can add a bank of resistors without having to place them one at a time or use the a DIP resistor and make a wiring mess.
    Jack
     
  8. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    So it is really like this?

    [​IMG]
     
  9. jm0825

    Thread Starter New Member

    Nov 9, 2009
    6
    0
    Yes it is like that
     
  10. swavi

    New Member

    Apr 3, 2013
    1
    0
    HELLO JM0825
    Sir please can u mail me the complete project and project report as soon as possible as I too am making the same and I would be very grateful to you if you mail it to me....Its really very urgent....my mail id is avinash.k.singh.20@gmail.com

    thanks
     
  11. bogalark

    New Member

    Apr 24, 2013
    12
    0
    hi jm0825
    can you please and please help me out with a similar project of the same type may be same...to build a laser range finder to measure at a distance of 70 mts (approx 200 feet), the components to be used and as you build it already,the laser transmitter and receiver circuits...may be you will be kind enough to send the complete circuit to my mail id- krishna_3426@yahoo.co.in

    thanks
     
  12. #12

    Expert

    Nov 30, 2010
    16,278
    6,790
    Jim hasn't been her for almost 3 years. He only did 6 posts and went away, never to be seen again.
     
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