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Author Topic: Sharp Infrared Proximity Sensor  (Read 2622 times)
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Hi all,

Im trying to connect some of these sensors to my Arduino board:

http://www.sparkfun.com/commerce/product_info.php?products_id=8959

Ideally Id like to attach 5. Does anyone know if I require one of these Phidget kits for the sensor to work?

http://www.active-robots.com/products/phidgets/phidgets/2008-250.jpg

Many thanks

Rich
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Interesting sensor. It seems to output a analog voltage relative to the distance of an object reflecting the infrared beam. It would seem to me that the sensor output voltage could be wired directly to an Arduino A/D input pin. Not sure what the second link is showing and how it would be used with this sensor.

One thing to keep in mind having looked at the data sheet link shown in Sparkfun and that is that the relationship to distance Vs measurement output voltage is not a linear function, so your code would have to deal with that.

Lefty
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thanks Lefty, I'm a beginner with all this though, could you explain what you mean by the output voltage being non-linear?

Thanks alot

Rich
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Well if the output voltage was linear then the measurement voltage would be say half the value at 10cm distance that it would be a 5cm distance. There is a chart in the data sheet showing the curve of output voltage Vs distance that better shows this relationship then I can explain. Over a narrow range of distance there can be a pretty close to linear relationship, but over it's full range it is clearly not linerar. Also not kind of a 'false' output voltage when distance is closer the 4cm, this would also have to be factored in depending on your physical mounting and application of this sensor.

Page 9 of the attached PDF shows this:


http://www.sparkfun.com/datasheets/Sensors/Infrared/GP2D120XJ00F_SS.pdf

Lefty
« Last Edit: December 16, 2008, 03:36:52 pm by retrolefty » Logged

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I see what you mean, thanks!

I don't think that will be a problem for what Im trying to do though, as I don't require an accurate measurement of distance. I intend to use the sensor to create a real time animation through MAX/MSP/Jitter, where a series of coloured squares respond to the proximity of a persons hand. (changing colour, becoming more vivid the closer the hand is to the sensor, etc)
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Should work fine for that kind of application. Have fun

Lefty
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one more question - could I link 3 of these sensors to the board at the same time?  Would I need a breadboard for that?

Thanks
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Yes, the Arduino has six (yes count them!) A/D input pins, so using three of them to use three of these sensors is very straight forward.

Lefty

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Does anybody know of a way to manage a large number of analog inputs. I'm considering a project where I would like to use over 100 proximity sensors at once. I would prefer to use Arduino. Is there some way to address this many signals to one (or a few) Arduino?
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Quote
I would like to use over 100 proximity sensors

thats complex... would need you to use some daisy chained multiplexers along with a solid plan on how you are going to power them up...
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