[SOLVED] Queueing System Small Project need help "no MCUs nor PICs" just basic and special ICs

[corpuralx]

Queueing System Small Project need help "no MCUs nor PICs" just basic and special ICs

As what the title says, Im currently building the said small project named queueing system, which is just basically an up counter with window number. The output would be, an up counter from 00 to 99 (two 7 segments), there will be 3 switches, 1 switch each for 3 windows (one 7 segment). So all in all, there will be three 7segments. each time I press either of switch1, switch2 or switch3, each counts up the number from 00 to 99, and displays the 1,2 or 3 dpending on the switch# pressed. I used 2 74LS192 ic counter and 1 74LS194 ic shift register counter. Everything works fine at proteus when I simulate it.

Now the problem, when I wired all conenctions at the breadboard, the only problem I have is the switch3 which should displays number 3 on the third 7 segment. When I press SW1 it displays 3 when it should be 1, if SW2, it still displays 3 same with SW3. But when I removed the connections from SW3, When SW1 is pressed, it displays 1, SW2 displays 2 and SW3 displays 0... yes 0. Basically, for SW3, pin1 and pin2 should be #3 and both should light, where it does but also affects SW1 and SW2.

I don't know what's the problem, it could be the diodes? DOes it matter the specific part/model of diode? Im just using a stocks of my diode, do i need 1n4148? or my connections?

Here's the schematic for my switch.



Any help is appreciated. Thanks

 

[chuckey]

Re: Queueing System Small Project need help "no MCUs nor PICs" just basic and special

The 74ls194 clocks the data on the the rising positive edge. So the data must be set up before this, i.e. the clock should be delayed. Try putting a 100 PF cap between the clock line and earth.
Frank