Sharp GP2D120 ir sensor range

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alasdair
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Post by alasdair »

I think i could maybe use an opto isolator to do this- It would work would it not?

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peterwaller
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Post by peterwaller »

No with an opto isolator the sender / receiver are completely internal no light goes in or out of the device. It is just a way of separating two circuit entirely while still passing a signal between them.

alasdair
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Post by alasdair »

Oh, i have just looked up what they are and you are correct, they are not what i am looking for.

I have just gone onto the Photo-reflector that you posted peter, as the maplin site has only just come back online. Do you know the range? (i have no experience in opto electrnics so i will need some help!) :D

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peterwaller
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Post by peterwaller »

The Maplin devices I was using was just to detect the edge white ring at about 5 mm. (very short range)

alasdair
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Post by alasdair »

Thats good. What voltage and Ampage can i put into them before they blow?

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Post by slurp »

alasdair wrote:Thats good. What voltage and Ampage can i put into them before they blow?
If you look at the Specification portion of the page the forward current is the usual you'd expect for an LED 20mA, but I'd expect 10-15mA is OK. The forward voltage (Vf) is 1.7V

I guess you know the calc for current limiting resistors.... if not look here:- http://www.minisumo.org.uk/EdgeDetection.php

regards,
Colin

alasdair
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Post by alasdair »

Thanks colin.

Peter, i am working on your board at the moment on PCB Wizard. Where do you get the optical array on the right of the schematic? ( i need to find dimension for the pins etc)

I am working on my sumo bot before i start my mouse. :D
Last edited by alasdair on Thu Sep 30, 2010 6:11 pm, edited 1 time in total.

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peterwaller
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Post by peterwaller »

Actually it is not a single physical array just individual senders and receivers.
The senders are SFH4580
The receivers are SFH3500FA
I had never noticed that the layout package had for some reason incremented the part numbers.
They are made by Osram and I bought them from Farnel but they don't seem to do them any more which probably means they either dropped them when the ROHS legislation came in or the newer version has a different part number.
Just looked on RS and they have the senders
http://uk.rs-online.com/web/search/sear ... rm=sfh4580
But only have the SFH3500 receivers which do not have the built in daylight filter.
http://uk.rs-online.com/web/search/sear ... rm=sfh3500
Last edited by peterwaller on Thu Sep 30, 2010 6:16 pm, edited 1 time in total.

alasdair
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Post by alasdair »

peterwaller wrote:Actually it is not a single physical array just individual senders and receivers.
The senders are SFH4580
The receivers are SFH3500FA
I had never noticed that the layout package had for some reason incremented the part numbers.
They are made by Osram and I bought them from Farnel but they don't seem to do them any more which probably means they either dropped them when the ROHS legislation came in or the newer version has a different part number.
Ah. I will search for them around the 'Tinternet' :D

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BeligerAnt
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Post by BeligerAnt »

Irritatingly Farnell changed their part number of every part when RoHS versions came in, even if the manufacturer didn't change the part number!
Search for IR emitters and photodiodes or phototransistors and make sure you get the same wavelength for each. You should be able to find 3mm or 5mm parts.
Gary, Team BeligerAnt

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