Squirrels have fuzzy tails.
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2. Soeren: in your picture infrared beam is getting wider with distance - this beam is collimated with one of lens that SHARP has inside, so its almost strainght (almost, because in fact, radius of this beam gets a little bigger)
I've some work with this sensor and it works like this:
IR LED is working (light is of course modulated) and first lens collimate its light (that LED is placed exactly in focal length) - we can say that behind that lens there is only ONE single ray of light without any radius (of course it's simplification)
that single ray gets to the object and the it's dispersed (NOT reflected as many people say but DISPERSED) as in that picture above
then another simplification - the object is so far from the sensor that any ray that gets to the second lens is parallel to any other - as a result light is focused on the PSD sensor which is placed again in focal plane
By the way, do you buy Sharps locally in Poland and if so, how much are they?I just returned from Warsaw and I'm still pretty amazed of how cheap everything is (booze, tobacco, dames, opera tickets, food, you name it), so perhaps I should get a load of components next time I go there
[...] You can then use the height of the IR sensors "wall" to calculate the degree of the returning light, and by using the total distance between the IR sender and reciever, you can calculate the actual distance.I know there are lenses as well, but the prinsip is right, isnt it? I will work out the simple formulas as well
[...] I REALLY think the "tutorial" on this site on how the sensor works is lacking very much important basic information. [...]
Hi,Quote from: Tomas on May 23, 2009, 01:52:08 PM[...] You can then use the height of the IR sensors "wall" to calculate the degree of the returning light, and by using the total distance between the IR sender and reciever, you can calculate the actual distance.I know there are lenses as well, but the prinsip is right, isnt it? I will work out the simple formulas as well Yes, if you by walls are portraying the effect of the focus point shifting on the CCD, but it sounds a bit off I'd say.It would be better, for understanding the concept, saying that each pixel of the CCD looks in a different direction/line and the one that spots it, represents a certain distance. Won't go in a thesis of course, but too many people is hung up on the light going from the LED to the CCD to comprehend the action. Turn it a bit around and it instantly becomes so much clearer.Quote from: Tomas on May 23, 2009, 01:52:08 PM[...] I REALLY think the "tutorial" on this site on how the sensor works is lacking very much important basic information. [...] The kind of info you want for a report/thesis is not needed to use it, it's more or less Plug'N'Pray.