View Full Version : How to detect presence of humans inside a room???

09-03-2011, 01:53 AM
I am thinking about making a project where the the lights/fans ad other electrical appliances in a room are switched off the moment no one is present inside the room.
I am thinking about using a PIR sensor to detect when a person enters a room. But the problem is that PIR sensor detects a change in heat. If a body with heat much more or less passes infront of it, only then it gives high output. But in my project, a lot of people may be inside the room for a long time. So the reference heat as sensed by the PIR sensor is that of human body. So if a person sits infront of the sensor, the sensor will think that since there is no movement, there is nobody inside the room. So it will shut off electricity.

So can anyone provide any ideas about how I can make my system fool proof?
I can use a combination of sensors. It is not necessary to use only PIR sensor. The only thing is that the system should be foolproof. There should be a way to detect the presence of humans inside the room

09-03-2011, 12:59 PM
There are PIR sensors that can detect motion. they can communicate via serial interface. having them on all the possible entry points will be the solution.

02-07-2012, 11:24 AM
if the room is properly lighted u can use algorithms of face recognition in computer vision

02-10-2012, 02:11 AM
RFID tags on the people and RFID reader are the best possible solution. The tags are quite small and can be made into an ID card, a thin sticker, a button etc.

02-11-2012, 12:18 PM
use Passive IR sensors....else thermal sensors..