Distance sensors

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#1
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hi
i want to know that whether i can use the IR sensor TSOP 1738 as distance
measurement sensor .?
or being more precise i want to get some kind of linear output from the receiver when ever the distance increases . i.e whenever the distance increases th output should go down linearly

If nebody knows the circuit please tell me
thanx in advance
Bye

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No, you cannot. Stop making new threads about it.

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I'm really sorry, I know that people don't like answers like "use search engine", but this looks like an exceptional case and it's a monday morning, so here, have a helpful link:

http://tinyurl.com/85857

The Dark Boxes are coming.

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hehe I love it!

---
Formerly Torby. Stitch626 just seemed a more descriptive nicname.

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Actually I think one could build a limited range sensor based on one of those demodulating IR receivers. Assumed that most of the world is gray in IR part of spectrum, we could slowly ramp the power of emitter until the reflected light is detected by the receiver. When we register reflected signal, the distance might be calculated as something like 1/(2*sqrt(output_power)). Sort of like in integrating ADC.

Of course this can't be used for precision measurement, but it might work for avoiding most obstacles that are not pitch black. Has anyone been doing something like this before? I'm interested too.

The Dark Boxes are coming.

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:lol: that should be a sticky at the top of the forum that everyone can easily link to!

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@svofski:

Unluckily, the saturation in the ir domain (something like the amout of reflection), will affect readings, so a clear white paper at the same distance than a light gray plastic box that is not planar will have a different amount of IR light reflected back even at the same distance. That will made an error in this reading.

Usually, short distance measurements using IR are performed by triangulation or position dependant sensors.

Guillem.

Guillem.
"Common sense is the least common of the senses" Anonymous.

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Aaaah too bad. Those triangulating sensors are expensive here. Perhaps I should start raiding flea markets for old polaroid cams instead.

The Dark Boxes are coming.

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Ultrasonic range finders will be particularly easy to use for 'medium' distances (20 cm to 10 meters), and not too difficult to implement by hardware.

Guillem.

Guillem.
"Common sense is the least common of the senses" Anonymous.

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I still would have to try to believe that IR sensor like I described will not work at least in bumper mode. When I did my shaft encoders, I could make the sensor "feel" most everything from distance of about 10 cm - yes, a cd would become "visible" from 30cm and my hand from 10cm, but still it could see stuff. Not suitable for distance measurement though, indeed.

I'm really hot on this kind of IR bumpers because I want to build an omnidirectional sensor. 8 emitters on the perimeter, a reflective cone/hemisphere pointing down above, and one sensor under the cone.

The Dark Boxes are coming.

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In fact, I saw an application (for mobile robots of course) that uses IR sensors as you describe. And in this case, they had two different outputs for each sensor that trips at two different levels (distances in theory). The lowest level warns about proximity, the highest one warns about collision. It worked fine. Also they use this kind of sensor to detect ground, in order to avoit falling down on an staircase.

Guillem.

Guillem.
"Common sense is the least common of the senses" Anonymous.