Simple Room Monitoring System Circuit Using Dual Sensor PIR and Microcontroller?

Hello everyone,

I am a 3rd year EE student and we have to design an electronic design project.I was wondering if anyone could me with an electronic circuit which is quite simple to design for a Room Monitoring System.We are thinking to design it using a PIR sensor and maybe use a microcontroller.We plan to use a plastic sheet as well so that the alarm doesnt generate false alarms due to dusts and insects.
Would be also interested to know whether Dual Sensor PIR with Pulse Count is a good PIR sensor to use it in our design? Thanks

This sounds like a pretty straightforward project and you're on the right track.

If you finish off this project early, maybe see if you can create a room monitoring system that uses a camera with real-time motion detection.

Send the camera data to a microcontroller or FPGA for processing of each frame and looks for changes in the "scene."

This type of systems allows you to actually track the object and determine a lot of additional information - such as the object's apparent size, shape, and speed.

If you can track the object, you could actively allow the camera to start panning in an effort to keep the "intruder" in view over the entire range of a pan/tilt unit.

Hi Joe,

Thank you for your reply.We are not thinking of having a camera to detect real-time motion at this stage.We are thinking to have comparators , resistors and capacitors and then connect it with a alarm/LED in order to alert others who are planning to entering the room.

I have no idea what you mean by pulse count.

Passive infrared motion detectors usually just look for a short term change in the signal from the PIR sensor. This is helped by a Fresnell lens that focuses any point to a set of vertical bars. Or conversely, you can think of the sensor only seeing vertical stripes in the room. As something above ambient temperature like a human walks along, it will cause changes in PIR signal due to the stripe pattern.

For a quick and dirty project, you can use a set of vertical slits instead of the Fresnell lens.