looking for a sensor for people counting

[everestman]

Hi,

I bought a PIR sensor (http://www.adafruit.com/products/189) for purpose of motion detection. However, I find it is not well suited for counting people who walk into a store assuming the sensor is kept near the entrance door.

I am looking to build a senor based solution where, ideally, if some one crosses an imaginary line across the door it should register a count.

Can some one advise on a sensor available in the market that would serve the purpose and which can be connected to an electric imp for processing the sensor data.

Thanks in advance

[zener]

What is the problem with the PIR sensor?

[adafruit_support_bill]

A PIR sensor is not good at distinguishing a single person from a group of people for counting. You can make them more directional with a shroud, but the re-triggering delay could be a problem if the people are passing too fast.

if some one crosses an imaginary line across the door it should register a count.

Sounds like a good application for an IR beam or laser & photodetector. Although it would still require some space between successive bodies crossing the line to get an accurate count.

[everestman]

can you point me to a IR, photo detector based sensor.

Also, I am looking for advise on if there is suggestions on casing available to put an electric imp, PIR sensor and battery together. Also, is using 3D printer to get a case made a economic option for low volume production.

Thanks,

[adafruit_support_bill]

You can build one out of a laser module and a photo-resistor:
http://www.adafruit.com/products/161
http://www.adafruit.com/products/1054
Just aim the laser beam at the photo-cell and the resistance will go up whenever the beam is broken.
The photocell tutorial page shows how to hook them up: http://www.ladyada.net/learn/sensors/cds.html