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COMBINATIONAL LOGIC PROJECT

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asolondon

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combinational logic problems

A railway station is designed to control and record the movement of
low, medium and high trucks. A bank of light is on one side of the railway
track while another bank of three photocells is on the other(opposite)
side.

Using logic gates construct a circuit which will light a lamp only when
a medium truck passes, but will be unaffected by low and high trucks.

(This logical ‘1’ output can be used to drive a counter).This logic
gates may include:

Flip flop

NOT gate

NOR gate

NOT-Exclusive

OR gate

AND gate
 

Bingo600

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combinational logic circuits projects

A nice assignment :)

Now you have described it ..

How would you solve it ???

/Bingo
 

E-design

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combinational logic design projects

Come on guys! This is elementary logic stuff
 

asolondon

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combinational logic gate projects

can i get the details of the elementary logic stuff?
 

ilker

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electronics logic project

go there:
 

mandrei

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combinational logic circuit projects

Hi asolondon

Your problem is verry similar to the mouse position detection (inside the mouse is a light source and 2 plastic disks wich obturate the light when you move the mouse ball in x, y directions- the problem is to find the x,y coordonates).

Or similar with the phase comparator problem (used in PLL's)...

Or similar whith the problem of synthessys of RS bistable using 2 NAND gates...

All those problems (and much more!!) had the solutions in asincron state machine theory!!!
 

VVV

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combinational logic circuit design+projects

The way I see the problem is a small truck will obstruct only the lower phototransistor, a medium truck will obstruct the lower two phototransistors and a large truck will obstruct all three.

In the schematic, I assumed that an unobstructed phototransistor will produce a HI.
So, three conditions have to be met simultanously for a HI output:
Lower two phototransistors output a LO and the upper one outputs a HI. Since these conditons have to be all true, you just need an AND and invert the signals from the lower two photodetectors. Any other combination is invalid.
 

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