Dual Beam People Counter Problem........

[fingers]

I'm making an electronic people counter (like you would find in a shop or library entrance) as a college project. It has to have 2 beams which must be broken in order for the counter to go up by 1 number.

The problem is that it must only count when beam 1 then beam 2 is broken, and not 2 then 1. Can anyone help? The whole device has to be done on a budget.
Thank you

 

[Nigel Goodwin]

I'm making an electronic people counter (like you would find in a shop or library entrance) as a college project. It has to have 2 beams which must be broken in order for the counter to go up by 1 number.

The problem is that it must only count when beam 1 then beam 2 is broken, and not 2 then 1. Can anyone help? The whole device has to be done on a budget.
Thank you

Apart from the sensors and optics all you need is a PIC and a display, an LCD text module would make it very simple to build, and easy to program. It shouldn't cost very much at all - the biggest expense would be the LCD module.

You could also easily make it count down for people leaving the room, simply by checking for 2 then 1 breaking.

 

[chemelec]

Even Cheaper, a simple circuit using a 4000 series IC can be made to do the logic and followed by a Discontinued Radio Shack Part.
An "LCD Electronic Counting Module". Part Number "277-302"

It is "Still Available" and any RS Dealer can order it for you.
I believe it costs around $18.00 US.

It runs on just one AA Battery and that battery will last OVER 10 Years.
Maximum Count Speed is about 7 per second, but not a problem for your application. (Unless you have Really Fast People) **SMILE**

Take care........Gary

 

[Sebi]

Possible solution...

 

[GraveYard_Killer]

as i could see, as what Nigel said, pic is the easiest way and the most accurate way for me as you could customize the dalay for the two beams to count. it could be cheaper by multiplexing 7 segment displays.

 

[Oznog]

as i could see, as what Nigel said, pic is the easiest way and the most accurate way for me as you could customize the dalay for the two beams to count. it could be cheaper by multiplexing 7 segment displays.

The microcontroller is also necessary for the discriminating code you will inevitably need to add if you want to do it right. Depends on if you want a good grade!

See, if you get beam 1 broken, then nothing, then 15 min later beam 2 is broken, that shouldn't count. It's got to be false. In fact, you might want to decrement the counter if the beams are triggered in reverse, based on the idea that someone turned back around to pick up a nickle they saw and then triggered them again going forward. Or light an alarm if someone enters backwards. Such show-off features get the A+'s.

 

[fingers]

Dual Beam Counter Problem.................

Would the circuit in the diagram work ok if stage 2 didn't occur (where both beams are broken at one point)? I was hoping to have the beams further apart to prevent children waving their arms infront of it.

Thanks for everyone's help so far, its been very helpful!

Grant

 

[Optikon]

In fact, you might want to decrement the counter if the beams are triggered in reverse, based on the idea that someone turned back around to pick up a nickle they saw and then triggered them again going forward.

In your final report, be sure to refer to this feature as "stray currency compensation" 8)