Proximity Sensor? Turn off/on lights in an area

Good morning all, This website is a great source of information. I have been coming here for a couple of weeks and wanted to see if someone could help me with a project I would like to start.
I have poured over the posts and other website resources but cannot seem to find direction for a proximity sensor I would like to create.
The schematics I do find seem to either be low voltage or a short distance type of sensor.
I would like to have lights (110 volt) and other appliances (tv, maybe radio) turn on when I enter a room. An average room being maybe 10x10, the sensors I am seeing would not cover this area. I would also like the lights and appliances to turn off after leaving the room. Am I approaching this wrong? Is a proximity sensor inline with some sort of motion detector maybe a better choice?(motion to turn off) It seems the proximity sensors (by definition) are only good within a couple of inches from the application. Any suggestions or links would definitley help me with which direction to goto. Thank you!

hi,
Most common proximity sensors are ultrasonic or passive infrared [PIR]

You can buy low cost PIR's, that can switch upto 2000W of lighting.

Does this help.?

aos said:

I would also like the lights and appliances to turn off after leaving the room. Am I approaching this wrong?

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That is the hardest part.My room light controller I have configured to operate like this.

PIR versus Infrared

Thanks to both of you it gives me some place to start, I was wondering (it's been about 15 yearstrying to get back into it) any suggestions on links or areas to search for ultrasonic or PIR circuit designs also?
Gayan, when you said that was the hardest part did you mean the area to cover to allow the circuit to pick up motion? Also, the circuit that was included (thanks again!) does it turn off the light as you leave the area?
So posts suggested a 55 timer chip-but I would like to stay away from a predetermined amount of time before the light is turned off-just when I leave that area or room.
As far as which to look into designing (PIR versus infrared) any suggestions as to which maybe easier to work with? (ease of design and availability of materials and schematics) Thank you for your time in answering me

aos said:

Thanks to both of you it gives me some place to start, I was wondering (it's been about 15 yearstrying to get back into it) any suggestions on links or areas to search for ultrasonic or PIR circuit designs also?
Gayan, when you said that was the hardest part did you mean the area to cover to allow the circuit to pick up motion? Also, the circuit that was included (thanks again!) does it turn off the light as you leave the area?
So posts suggested a 55 timer chip-but I would like to stay away from a predetermined amount of time before the light is turned off-just when I leave that area or room.

Modern PIR's can have an in built time out/off delay

As far as which to look into designing (PIR versus infrared)
PIR [passive infra red] is infra red. Do you mean ultrasonic, if yes I would avoid ultrasonic sensors, they can be tempremental, subject to air draughts and blowing curtains.

The main drawback with any of these 'motion' sensors you must keep moving in the room,! , else the lights go out..

any suggestions as to which maybe easier to work with? (ease of design and availability of materials and schematics) Thank you for your time in answering me

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Whats the actual application you have in mind.?

PIR versus Infrared

Hello again, by the way I was starting to research these chips the PIC12f675 and the lm358 ic, it looks like the IC is only 30 volts or less and the pic chip needs to be programed-am I correct?
My application is to turn on under counter lights in a kitchen (110 volt) as you enter the kitchen, then turn off as you leave. It would be nice to include this circuit in other places, when you first enter a garage, enter a doorway, at the beginning and end of a hallway, etc.
I have not messed around with electronics for several years, so getting back into it now would be nice to start with basic circuits and plans.
I was referring to your first post, maybe I read it wrong, the:

Most common proximity sensors are ultrasonic or passive infrared [PIR]

You can buy low cost PIR's, that can switch upto 2000W of lighting.

I thought there were 2 types that may fit what I was trying to accomplish-

aos said:

Hello again, by the way I was starting to research these chips the PIC12f675 and the lm358 ic, it looks like the IC is only 30 volts or less and the pic chip needs to be programed-am I correct?

The PIC is 5V and the LM358 opa is about 30V.
The PIC needs a program.

My application is to turn on under counter lights in a kitchen (110 volt) as you enter the kitchen, then turn off as you leave. It would be nice to include this circuit in other places, when you first enter a garage, enter a doorway, at the beginning and end of a hallway, etc.
I have not messed around with electronics for several years, so getting back into it now would be nice to start with basic circuits and plans.
I was referring to your first post, maybe I read it wrong, the:

Most common proximity sensors are ultrasonic or passive infrared [PIR]

You can buy low cost PIR's, that can switch upto 2000W of lighting.

I thought there were 2 types that may fit what I was trying to accomplish-

The two common types are ultrasonic sound sensors and passive infra red which detect body heat.

Click to expand...

Does this answer your questions.?


**broken link removed**

http://www.pirsensors.com/index.htm

ericgibbs said:

Does this answer your questions.?


**broken link removed**

http://www.pirsensors.com/index.htm

Click to expand...

Yes! Thank you!!

Hi aos

Eric gave you some nice information.

The PIR Motion sensors works if there is some motion in your room or in your kitchen.
The distance & the angle that works the PIR Motion sensors is quit enough for a room or a hall. The thing is it if there is no motion then it won’t give any output.

Most PIR Motion sensors I have seen they are design to apply a front door of a shop or the main door in the house instead of ringing a bell it will automatically ring a sound or light.

Apart from that to design a fully automatic room light is a pretty challenge.
Anyway my method is hard for you. Just get an idea.

How my design works

When a person enters in a room it will turn on the output & if the person leaves the room it will switch off the output.

If you are inside the room the light will be turned on, if another person comes it will still stay turned on. The light will be turned off all the people’s leaves the room. That is the nice part in the design.

My solution is you use PIR motion sensors for your application as Eric mentioned.

I'm interested in this too. Ive always wanted the house that I build to use this kind of technology (lights turn on as you walk in, turn off as you walk out - or maybe even accent lighting, and you can turn the rest on by yourself). Would something like this work?
http://www.pirsensors.com/pir_tec-lc780hd_780lv.htm
Perhaps you could use it to switch a TRIAC or a relay, that would flip your lights on as you enter and off as you exit.

What about a small microwave movement detector coupled to an SSR or relay, most of the small designs I have seen use the doppler shift principal to detect movement. I have seen relatively cheap microwave detector modules for use with car alarms, shouldn't be too difficult to press one of those into your application. At least it would allow you to hide it within the room without having to worry about the detection field being obscured by furniture or corners in the room etc.

rgds

ParkingLotLust said:

I'm interested in this too. Ive always wanted the house that I build to use this kind of technology (lights turn on as you walk in, turn off as you walk out - or maybe even accent lighting, and you can turn the rest on by yourself). Would something like this work?
http://www.pirsensors.com/pir_tec-lc780hd_780lv.htm
Perhaps you could use it to switch a TRIAC or a relay, that would flip your lights on as you enter and off as you exit.

Click to expand...

hi,
The type of PIR sensor you have posted will switch upto 2KW of lighting directly.
Usually they also have an adjustabe ON time, from a few seconds to minutues.

The only minor drawback the PIR detects changes in body heat/movement, so if you just sit still, the lights will go OFF until you move again.

They are handy for a hallway that lights up when you walk from one room to another, have the ON time set for 30secs [ goes OFF after 30secs of no movement]

I have pressure mats under the carpets in my hallway to control the lighting, been in use for over 25 years, never a problem.

They also play a part in the house security alarms.

hi guys
cant the same purpose be served by using a sensor with an SCR

umar karim said:

hi guys
cant the same purpose be served by using a sensor with an SCR

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hi,
Wouldn't that give you half the light output of the lamp, that is half rectification by the SCR.?

Most commercial PIR sensors have a inbuilt relay, rated upto 10A.

It would cost more to make your sensor...

The other type detector is the one that will compare to the reference scene and detect a new object. To describe an implementation : some cellphones /or pcs with cameras have 3rd party software that takes a snapshot of a protected area, and will compare the scene every second or so. The processing will compensate for variables like daylight etc, and can detect an intrusion, even when there is no new motion - where PIR fails.

A high speed microcontroller can suffice. Dice a zone (webcam, analogue video, LDR matrix? ) into a matrix, and then measure the analogue voltages and compare with the reference zone. Apply matrix transformations to adjust for light.