Sensor to detect Human Presence

I would go more for computer vision with facial recognition for a passive system.  The resolution on PIR sensors would be overwhelmed by heat from a fire in the vicinity,  I suppose you could theoretically use a Surface Acoustic Wave sensor at floor level to detect movement on X-Y axes, but I would think you'd have problems if people got packed in.  You could use a FLIR array to count objects a a certain temperature, i.e.; a human nose is around 33-35 degrees C when in a "normal living area".

Another system which could be effective for a group who had cell phones would be to count the number of different IME's that could be polled.

Much would depend upon the environment: Is this an open area?  Is it a cubicle farm where there are many small enclosed areas?  How large is the area, and expected number of people?  Is it possible to issue each person an active transmitter with an ID badge?  Would there be a choke-point where RFID badges would give you an effective count?  Is this an area where an active fire would be anticipated, or one that would be evacuated as a precaution?  Quite a few questions would need consideration before you started looking at modalities.

Try the OMRON thermal sensor D6T available from Digikey and Mouser.

Most intruder alarms use Passive Infrared detectors, that pick up on a rise of IR from a body - Good for about 10m (31ft) in optimal conditions.  These won't differentiate between a human and, say, a raccoon climbing on the gate.

Depending upon what's outside the gate you could also use a motion detection system - That won't work if there's traffic close by the gate.  Motion detection is also commonly used within a perimeter.   The better detectors are capable of focused field and fairly long-range,  The lower-priced add-on boards are usually good to about 8m (25ft).

I don't know what system you're using for a host, but there are common brands of these sensors on breakout or add-on boards for the most common microcontrollers and single-board computers.  High-end IP cameras also have motion-detection and alarm capability.

yup, that pretty much covers it, you can also consider putting a magnetic switch on the gate itself as an additional measure to detect the intruder / visito or Laser / IR beams at strategic places, these could be high enough to avoid being tripped by smaller animals, they may trip for larger preditors like Bears and Sasquatch, or the odd moose

Hi

This may be a 2 years late reply but

you can use pedestrain detection in opencv

Pedestrian Detection OpenCV - PyImageSearch

today open-CV output has become much more robust and reliable and you can use it with any small board which has Linux and some camera interface.

Also the more you increase camera quality the better the results will be.It is Cross platform and you can use c/c++/python/java/ruby and many more languages with same library

Also I have a vivid Idea of having sensors beneath the roads and tiles which detect human like ( 2 legged) footsteps to determine presence of a human. A network of sensors beneath our ground that tracks not just our presence but our motion, direction and position. How about this way of doing it ?

Listen  I have solution like that you can use 2 ir sensors at your door and make a visitor counter . At each entry at your door,  controller will count it,  so we can say that there is person in home.

CO2, if calibrated correctly and the room has the ventilation set just right a person will increase the CO2 levels but when they are not there the CO2 levels will decrease. This may take some trial and error but I'm sure it can be done.

Hi!

Could anyone give me some advice if I want to build a portable device that detects human presence near it? Ideally a pedestrian can use it to check if anyone is following him. Can this possibly be done with sensors, or should I just use an infrared camera and image processing techniques?

I'm pretty new to this topic. Any help will be appreciated. Thank you very much!

@Hi,

Whether we can use the D6T-44L / D6T-8L Thermal sensor in a public places where there is lot of crowd such as playground,shopping mall and so on....michaelwylie