Need help on an electronical project, please...

[Drizzt]

Hi all...
I want to do a thing (if I can, before christmas), but I have a few knowing on how to setup infrared.


So, here's my situation:
I have 2 points. One is fixed, the other one moves. I want to measure the distance between the two points using infrared.
I put the receiver on the fixed point and the trasmitter on the moveable point.

But, I do not find any info on how to interface those two, on wich to choose, etc. etc...

All I want is a signal on the receiver that is proportional to the distance between the two.


Can anyone help?



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Italian Guy, Bad English

D'ya want an Italian version?

[Himself]

Well, the only ways to measure the distance would be the intensity of the light hitting the receiver or sending a pulse and measuring how long it took to get there. The latter isn't a likely solution though.

You probably want to arrange it so that the angle between the two increases as you move and meaure the intensity. The amount of variation as you leave the center of the beam might not be different enough. As for how proportional it would be I have no idea.

I'd look at it as an analog project, no real interfacing required. You could use a PIC12C671 from http://www.microchip.com/ for measuring the intensity with it's built in A/D converter and go from there programatically. Or you could use a comparator circuit to latch something, depends on what you are doing. I wouldn't use IR receivers, just an IR transister and LED.

[Greebe]

Drizzt,

the only ways to measure the distance would be the intensity of the light hitting the receiver or sending a pulse and measuring how long it took to get there. The latter isn't a likely solution though.

This is incorrect.

Pulse detction is truely the best/only way to go and is akin to radar/sonar, with the exception being only the wavelength used. If pulsed fast (can be in the 1 mHz range easy!) there would be no problem of constantly readout.

Pulse range detection is commonly used in (as I said) radar/sonar, including police and military types, fish finders, even those spiffy baseball/tennis ball speed guns, ultrasonic tape measures, laser range finders , etc. Thus the same technology can be applied to visible/infrared range finders.

[Drizzt]

Well, I want to measure the intensity of the light 'cause I need a continuous value (and don't want to use complex things).

I have no probs on the angle, 'cause the moving point is always in front of the other, always at the same height (is there an english expression to say that?).

And for the receiver, yup, I already wanted to use an IR transister, but did forget to specify ^_^;;


I'm looking at your link, thanks a lot!

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Italian Guy, Bad English

D'ya want an Italian version?

[Himself]

Eem, when was the last time you shoped for IR parts?