up down counter

[maruf10]

i am trying to design an up down counter circuit which will increment counter when a person enters and decrement when a person leaves a room.
but the problem is,how will i pass 1/0 when a person enters/leaves a room to up/down the counter?

i want to add some more things.
it will be a mod-60 up down counter
there is only one door for entrance and leaving
assuming that no person will try to trick the counter
i have already designed the counter circuit and seven segment display
how to pass 1/0 to the counter?
i have tried to do but at the end of process everything is wrong

i am totally confused.
need a block diagram badly.

thanks is advance.

 

[Wond3rboy]

Firstly, when will you know whether a person is leaving or entering a room?Time wise?

A simple approach i did was use an ASM.I used two doors,one for entering and the other for leaving.Although the counter was less(it was just for practice).

About your question you can use a LED and a photo resistor to detect the disruption although the duration can eb a problem else use a photo sensor.

 

[KMoffett]

Think quadrature decoder. Gives direction and count for up-down counter. Two detector beam sensors...A and B...at the door(s). A person entering the room breaks A first, then B. A person leaving the room breaks B first then A.

This might help: **broken link removed**

Ken