Hello,
I have to design a circuit for a device to detect any motion in front of the device upto 2 metres. I have tried with Ir reflection sensor. but couldnt acheive the range. Then, I found out a circuit in internet which works on passive detection of shadows.
http://www.electronicsforu.com/elec...ticle_type=1&title=Shadow&id=367#.U8S4v_mSznI
so, basically it takes in the ambient light and when there is a obstacle in front of the sensor, output is triggered. As mentioned in the circuit about using L14F1 as sensor, I could not get that part where i am living. So, I used a anormal phototransistor with some black sheilding around it. It seems to be working onfor 40 cms.
1. which type of sensor should i look out for. what are the specifications that i need to look for this application( detect fast change in light upto 2 metres with narrow detection)
2. My major problem is I do not know if this circuit works properly for fast light changes. I need to drive a dc motor at output for 5 sec whenever the sensor detects a movement upto 2 metres.
3. Is there any other kind of low cost and effective sensor or method for this kind of application??
I am a beginner to this field. I am willing to learn by doing. so,any suggestions or advices are greatly appreciated

Thanks in advance

 

there are plenty of motion detectors around to turn on lights and such. most are adjustable for sensativity. look up PIR, (passive infra red) detectors.

 

May not help much but when I was faced with the same issue I just used a cheap video camera tied to a stand alone video motion sensor. Problem is the motion sensor I used is no longer manfactured.

http://www.saelig.com/product/VI001.htm

No real help but may give you food for thought..

<Edit> Awe heck, 2 meters is only about 6 1/2 feet, I was thinking you needed some real distance. The PIR sensors already mentioned will work fine at that distance..

 

But, PIR sensor is expensive. I am looking for a low cost solution. And also PIr sensor works for a wide angle. the output should be triggered when someone passes by the device.

I have tried a device which uses a normal photosensor for a similar kind of application.
http://tronixstuff.com/tag/glade/
so, please suggest me any low cost solution for the similar kind of application

 

Ultrasonic distance sensing will work at that range

 

Here's a PIR for $10 USD.

https://www.sparkfun.com/products/8630

What is your upper total cost budget?

John

 

http://www.mpja.com/PIR-Motion-Dete...duino-Compatible-Sensor/productinfo/19517 SC/

and it is only $3.95, I bought several just to have.

 

PIR modules for about $3 on ebay.

 

PIR modules for about $3 on ebay.

*inc shipping*

I used to have an eBay account (feedback score 511) -- until they kicked me off for shaking up peadophiles.