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Topic: Proximity with IR emitter and detector (Read 1 time) previous topic - next topic

max246

I want to ask how can I build a IR proximity similar to this video: http://www.youtube.com/watch?v=Vqcvmh_9rBo and also I want to calibrate it to put under a piece of glass so I can put any object on it and detect it.
I dont really know which kind of emitter and detector should I buy because there are a lot of them but I want to get a stronger one that can work with a piece of glass.

I bought these two types of IR:
https://www.adafruit.com/products/387
https://www.adafruit.com/products/157

but I am not sure that is going to work.

Boffin1

Do you want to measure the actual value of reflected IR ?  or just detect it's presence if a target reflects it?
With my mobile phone I can call people and talk to them -  how smart can you get ?

max246

Just want to catch if there is an object that reflect the IR signal

Boffin1

rather chop the signal to the IRED at 38 Khz, and use a IR detector module to pick op the signal.

It will ignore ambient lighting etc, and you can adjust the LED current to set the miniumum detect level.
With my mobile phone I can call people and talk to them -  how smart can you get ?

max246

These pieces that I have got, are good for that "experiment" ?

Chagrin

http://www.arcfn.com/2010/03/detecting-ir-beam-break-with-arduino-ir.html

Be careful and note that your IR receiver is not designed to output a continuous signal; see page 5 of the IR receiver's datasheet and it will show that when it detects a continuous beam it will only show a signal for about .0013 seconds.  You need to turn off/on your IR beam intermittently to keep testing for an object.

Boffin1

Heres an experiment I did with chopping the 38 Khz from the Arduino, I was using it to send data.

http://arduino.cc/forum/index.php/topic,128825.0.html
With my mobile phone I can call people and talk to them -  how smart can you get ?

max246

I might to know the analog value to get if the signal is far away or close to the receiver, in that way I should be able to calibrate with a piece of glass or I am wrong?

Boffin1

the only way you can measure signal strength with an IR module, is to see at what range ( or strength of LED pulses ) it fails to output anything.

Are you going to detect the same target each time ?, as different materials have different reflection...
With my mobile phone I can call people and talk to them -  how smart can you get ?

max246

Well, the project will be something like that: http://www.youtube.com/watch?v=h5n0rw8wo14 but instead of the piece of plastic, there will be a piece of glass.
On the top of this glass I want to put a cup, business card, plate, etc... and the IR should detects it!

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