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

 

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.

 

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

 

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.

 

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

 

Figure B will work correctly. In the A circuit, the switches are invisible to the IC.

 

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

 

So it is really like this?

 

Yes it is like that

 

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

 

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

 

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