Suggestion for cameras/detectors which would detect human presence in a room

Hi all,
Guys..!! i have a idea on my mind. Its not new and probably has been done before. But i want to implement it in a home level and it should be cost effective. What i have in mind goes like this..

Half the population in the world forget to switch off the fan and lights in a room before going out and thus it leads to enormous power bills and wastage for the individuals and the organisation. So i wanted to develop a device which switches off the power supply in a room when no one is present. So i went about asking a professor of mine for help and he suggested that i design a device using the 8051 microcontroller. Which is well and good, in addition i need a ir camera of some sort to detector to detect human presence. and transmit a message to switch off the current in the room if no humans are detected. SO do u have any ideas as to what type of cameras, any model numbers etc.. and also if there are better technologies than ir cameras to suit my needs.. I would really appreciate it if u could help me. thanks in advance..

A home Project

you can modify automatic room light controller using 89c51 by binu ji see https://www.8051projects.info/proj.asp?ID=39

Re: A home Project

U can use Pyroelectric Infrared sensors or PIR Motion Detection Sensor Module (RKI-1370)

Interface this with 8051 micrcontroller.
Find the attached useful files
**broken link removed**
https://robokits.co.in/documentation/PIR Sensor Module.pdf

Mod: Do not upload anything what you get on the net for free. Just links will suffice. Take this as a pre-warning.

Re: A home Project

@above: Yes.. thanks a lot but the problem is that i have a room of 35 by 35(give or take 5) and the sensors listed can detect only for around 6-7 feet. So i am wondering as to how many sensors should i put up..??

Re: A home Project

I think the PIR sensor is the way to go. Start looking for sensors used in burglar alarm systems. You might even be able to find an off-the-shelf module that will require a minimum of work to get it interfaced with your uC.

Here is a cheap module that is good for 20 feet. If this is just a one-off proof of concept project, you could probably get away with just putting one in each corner of the room.

**broken link removed**

Re: A home Project

@nick:

Hey thanks a lot man.. i will try that.. one in each corner will be sufficient i guess.. will let you know of any other developments and queries..

Re: A home Project

There is one problem with PIR sensors that just came to mind. These sensors detect movement. The problem here is if somebody is sitting still, perhaps reading a book. You have to make sure that this isn't interpreted as the room being empty.

I found this product from Leviton, but the way they get around this non-movement issue is simply to use a settable timer to turn off the light after X minutes of no movement is detected. That's a bit of a kludge, IMHO. Imagine how annoying it would be if while reading a book, every 15 minutes the light goes off.

**broken link removed**

There must be a better way. That link still has some interesting PDF files describing how this switch works.

A quick Google search of the term "occupancy sensor" showed some promising links.

Re: A home Project

Nick C. said:

There is one problem with PIR sensors that just came to mind. These sensors detect movement. The problem here is if somebody is sitting still, perhaps reading a book. You have to make sure that this isn't interpreted as the room being empty..

Click to expand...

PIR motion sensors are very sensitive an usually the sensistivity can be set as per requirement, through on board jumpers in most of the modules. The PIR cannot detect a human body only if he/she stands or sits in a dead position. Mean absolute 0 movement. Rest every minute movements of even the torso or the hand is also detected while in motion.