Incrementing or decrementing a counter

Hello Everyone!

I am an Electronics and Communications Engineering Student and I'm in my final year. We have this project on our microprocessor and one of its features is that when a person or people enter through a door or exits using it, it would either increment or decrement a counter triggered by a sensor. The problem is I still don't know what kind of sensor can be used to do such a job for a single door for entrance and exit. I hope you could help me on this one.

Good day
*** bless.
^_^

An IR transmitter and IR photo detector can be used. One side of the door will have IR transmitter and the other side will have IR detector. IR will be falling on the detector continuosly. Whenever a person abstructs the IR path that will be dtected by IR connected to uC and the counter is incremented which can be displayed on & segment display or LCD.

this seems to be a classic repeat thesis project.
The best design is one that includes a path loss study with attention to SNR from all possible stray noise sources.

Ideal counter is one that is Reliable, cheap, manufacturable and useful. This is measured by the Error rate and commonly called False Positive ( mistaken count or multiple counts) and True Negative ( missed event) and any parameters you wish to impose.

This can be determined by characterizing noise types and levels, signal types & levels, noise improvement factors such as BW reduction to an ideal matched receiver, the use of narrow band vs broad band to match the time response of the data ( slow transition time) the quality of the receiver using optimal methods of discrimination vs crude methods. (matched receiver using synchronous detection and integration of the noise symbol interval, adaptive gain control, etc)

The design is actually trivial and could be done with a few parts , but the analysis expands awareness of general communication path loss designs.

IR is indeed the most cost-effective solution and already implemented in decades of home consumer products.

Not only could you have one gate but dozens of gates side by side without cross-talk;
such as using physical apertures ( optical beam-forming with adjacent emitter rejection, OOK
or ASK modulation at different carrier freq. commonly used with 20 ~50KHz SIR
or IRDA or IRDA2 with TDM for adjacent gates in a synchronous method

These are just physical layers but the other layers can be adapted for your special purpose.

( i have used IR emitters and IRDA2 receivers with a deep 5mm aperture to detect an object as small as a resistor wire cross the 1 meter beam path. )

I will leave the details for you to figure out on how much path loss you can tolerate with 50mA (or more) pulsed IR and common IR receivers (3 types suggested above) and learn the tradeoff for path-loss vs power bandwidth product and required amount of noise rejection (hystersis and time filtering)

Of course the user interface ( the counter) can be as sophisticated as you want, from a calculator (+1====....) to a PIC controller to display to a tiny PC with ethernet interface with webpage statistics. You can even use dual detectors to determine speed and direction of occupant passing the path and adapt it to car counting and speed detection.


Make sure you start with a general spec for inputs , outputs, processing without implementation specifics, environmental specs and power availability, range and single sided method or dual sided method of sensing, with measureable parameters such as cost target, installation cost, error rates for false positives, true negatives with range of objects and intended operating locations. Include a design review process and a design validation plan with results against your original specs.

Digital-Visitor-Counter-(AT89C2051)
https://www.8051projects.info/circuit.asp?im=visitor&desc=Digital-Visitor-Counter-(AT89C2051


https://kitsnspares.com/admin/pdffiles/BiDirectional Visitor Counter.pdf

@tpetar< I wonder what the range is for error free performance with people wearing dark clothing? How are noisy transitions filtered?

Here is what actually you need... WITHOUT ANY KIND OF CONTROLLER/PROCESSOR

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Jigar 4 Electronics said:

Here is what actually you need... WITHOUT ANY KIND OF CONTROLLER/PROCESSOR

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Click to expand...

And one worker to count leds blinking. :wink:

tpetar said:

And one worker to count leds blinking. :wink:

Click to expand...

LOL...you can add a counter + 7 segment LCD circuit to do so.