i desperatly need ur help..plzzz

S

sanjana

New Member

• Oct 31, 2009

• #1

i need to construct a entry exit counter for room. the device need to have a reset switch to manually set the count to zero. i know how to build a counter bt i want to know the circuit which differentiates between entry and exit and i also dont know about the reset switch. plz help me out.....

regards

 

Gayan Soyza

Active Member

• Oct 31, 2009

• #2

You need to develop a finite state system.

This is the logic.

person is moving from outside to room

00
10
11
01
00

person is moving from room to outside

00
01
11
10
00

 

MrDEB

Well-Known Member

• Oct 31, 2009

• #3

I posted one several weeks ago
all it was consisted of a D flip flop and an up down counter, 2 sensors.
will try and locate

 

MrDEB

Well-Known Member

• Oct 31, 2009

• #4

link to circuit

here is a up down counter that counts # in minus number out
look about 3/4 of page down
synercious rotary counter.
could be adapted for your app very easily.
if you wanted two seperate counters just build two circuits.

 

MrDEB

Well-Known Member

• Oct 31, 2009

• #5

Message is unavailable.

 

C

colin55

Well-Known Member

• Oct 31, 2009

• #6

Here is an up/down counter for lifts:
**broken link removed**

The .asm for the PIC chip:

http://www.talkingelectronics.com/projects/Elektor/Lift Counter/files/LiftCounterFinal-asm.txt

 

E

electronspeed

New Member

• Oct 31, 2009

• #7

You may go for three sensors say you use IR TX Rx,A & B.So if a person enters the room all two sensors will give output but first A will give first & then B.Exactly opposite will happen when person moves out of the room.AND their o/p & hence determine whether the person is moving in or out

 

S

sanjana

New Member

• Oct 31, 2009

• #8

@electron speed

thanx..i know the concept but i don't know how the circuit should be.can u please tel me the detailed circuit ,which all ic should i use?

 

E

electronspeed

New Member

• Nov 1, 2009

• #9

Sorry to mention 3 ,two tx rx sensors are sufficient here.I guess your distance requirement will not be more than (2-3)m.So Google for finding models of your specification and contact your nearest electronics vendor.For AND gates you may use 7400.Now choice of counter again depends on your upper limit of count.74163 is a 4 bit counter sot will count to a maximum 15.Next AND the 2 o/p pass this o/p to a NOT gate(7404).Finally o/p of NOT gate to your two counters.

 

E

electronspeed

New Member

• Nov 1, 2009

• #10

contd.........
If you want to display the number go for 7 segment display.Find any of them & connect to your counter.Again here you require two displays.