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uhhh, when you buy it look at what it says?
what about those pretty pictures?
please explain what you want me to tell you? im not understanding fully? do you want me to tell you what they are?
well think about it, if it works on a mirror but not paper the ir led is not bright enough, there is not enough light to bounce back off the paper as most is getting absorbed. if you can get your hands on a higher brightness one try it with that, or try moving the sonsor closer to the paper. but generally black as a color in general absorbs lots of light.
You should be able to use that with paper, not just a mirror.There are some very good details here:http://www.societyofrobots.com/schematics_infraredemitdet.shtml
does it read anything if you have them facing each other? also have you tested the photodiode without having the led turned on as there could be something else effecting it.
since thats just a plain photodiode, I would image that you would first need to run it across a transistor(effectively replicating a phototransistor) and then use a potential divider to output any useable signal. You cant just connect that type of photodiode straight to a microcontroller without doing something with it first
i ever connect circuit like i posted below but doing this will not give any respon to the mirror or white paper. worst .
Hi,Quote from: theanxin on April 17, 2009, 10:30:20 AMi ever connect circuit like i posted below but doing this will not give any respon to the mirror or white paper. worst .That should actually be the easiest circuit for you to get to work, as the important parameters can be set individually.R1 should be set for a reasonable current through the IR-LED.R2 should be selected after the amount of ambient light - a trimmer could be used with or without a serially connected resistor.R3 sets the input impedance and should be equal to the average impedance on the non-inverting input (the parallel value of R2 and the average impedance of the photo transistor in the range of light it will see).R4 together with R3 sets the gain and like R2 could be made variable to dial in the optimum value.
phototransistor?? mind to show me the picture of photodiode compare with phototransistor?? how to recognize between photodiode and phototransistor?
Hi,Quote from: theanxin on April 19, 2009, 11:22:22 AMphototransistor?? mind to show me the picture of photodiode compare with phototransistor?? how to recognize between photodiode and phototransistor?Photodiode:Phototransistor:In short... You can't allways tell the difference by just looking at the physical component.The schematic you posted had a phototransistor, but a photo diode could be used instead.
what is the medium use for photodiode and phototransistor
he wants to know what they are generally used for, which i wouldn't have a clue about
i must know more about photodiode compare with LDR after applying on the line follower without microcontroller because i will question by my lecturer about it. That's why i have to get to know more information about its function, features and else after applying on the line follower without microcontroller .
BUT Now i still find out why infrared light only reflect on mirror to the photodiode but white paper cant after applying on the line follower without microcontroller. Im sure that i will be question by my lecturer about this.
Hi,Quote from: theanxin on April 20, 2009, 05:54:27 AMi must know more about photodiode compare with LDR after applying on the line follower without microcontroller because i will question by my lecturer about it. That's why i have to get to know more information about its function, features and else after applying on the line follower without microcontroller . Ahhh, you want others to do your school work Quote from: theanxin on April 20, 2009, 05:54:27 AMBUT Now i still find out why infrared light only reflect on mirror to the photodiode but white paper cant after applying on the line follower without microcontroller. Im sure that i will be question by my lecturer about this. As I told you... White (or almost any other colour) paper will reflect IR in adequate doses, just reread my post with comments on the components.You need to first get the bias correct and then adjust the gain of the amplifier to whatever is needed, but remember that ambient light contains lots of IR.Pause a bit on the questions here and get your hands dirty for a while... That's the only way to get some experience.Btw. A single modulated IRLED and phototransistor can span a mile or more if used with a lens and/or a parabolic mirror.