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Topic: Can you use two IR transistors and and IR LED to pan a turret? (Read 2578 times) previous topic - next topic

David82

Apr 12, 2013, 06:48 pm Last Edit: Apr 13, 2013, 04:22 pm by David82 Reason: 1
You would have two IR transistors pointing not quite straight ahead but a little away from each other. They would pan a servo or motor such that they stop when the reading from each Ir transistor was about even, meaning the turret is pointed at the IR led. How far away would that work, roughly, for a normal LED? Are we talking 10ft or 100ft? Has anyone messed with this? If the range is short, is there a better sensor to use besides a camera?

Edit:

What I'm asking about is essentially the same thing as a sun tracker.

http://www.youtube.com/watch?v=bHFCJ7TXcM4

except it will need to follow an IR LED or small cluster of LEDs and be much faster on the response time. I know the servo can move much faster but maybe there is something else limiting the speed like the response time of the phototransistor. Do any of you with experience with this stuff thing that it will be able to work with those modifications?

zoomkat

perhaps you could experiment with a tv IR remote control and draw some conclusions.
Google forum search: Use Google Advanced Search and use Http://forum.arduino.cc/index in the "site or domain:" box.

David82

THat's the same amount of work as building the whole thing. I'd like to know so that I can skip that and use a camera if the range isn't going to be good.

zoomkat


THat's the same amount of work as building the whole thing. I'd like to know so that I can skip that and use a camera if the range isn't going to be good.


Use a camera for what? You might give more specific info on what you want to do with a camera, and what a camera has to do with "range".
Google forum search: Use Google Advanced Search and use Http://forum.arduino.cc/index in the "site or domain:" box.

David82

.... I thought it was already clear.

I'll simplify it: What is the range the an IR photo transistor will detect a standard IR LED?

Robin2

11.537





Really, there is no answer to your question.

What LED?

What photo transistor?

What transistor amplifier?

What do you mean by "detect"?

What ambient light level?

What nearby reflecting surfaces?

etc..

etc ...

And how do you suppose a camera would be better?

Even if the photo-transistors could respond to light from the LED would there be sufficient difference to allow you to use the difference to control direction?

How accurately do you want the direction to be controlled, +/- how many degrees?

I don't think your project is at all simple and you will probably need a lot of experimentation which may ultimately fail.

...R

HazardsMind

By any chance are you reffering to laser targeting? To where to point the laser and the turret follows.
My GitHub:
https://github.com/AndrewMascolo?tab=repositories

David82

#7
Apr 12, 2013, 10:26 pm Last Edit: Apr 12, 2013, 10:28 pm by David82 Reason: 1

What LED? a standard size IR LED

What photo transistor? an standard IR phototransistor

What transistor amplifier? none

What do you mean by "detect"? have an analog output a value different from it's previous value

What ambient light level? typical office lighting or darker

What nearby reflecting surfaces? none

There you go, it's still simple. I just want a response from someone who has already worked on something similar.

David82


By any chance are you reffering to laser targeting? To where to point the laser and the turret follows.
nope. Just Just use the balancing of IR phototransistor values to pan a turret toward an IR LED. Really simple stuff. Someone has to have already done this before..

AWOL

Quote
I just want a response from someone who has already worked with these parts.

Which parts?
You haven't specified any parts.
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

HazardsMind

My GitHub:
https://github.com/AndrewMascolo?tab=repositories

AWOL

OK, here's the answer you want to hear: it will work and it will be effective, and you probably don't need a processor to do it.

Now, what are you going to do about seduction by other environmental sources of IR?
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

David82


Quote
I just want a response from someone who has already worked with these parts.

Which parts?
You haven't specified any parts.
You're being unnecessarily picky. The level of detail you're asking for isn't relevant but just so you can get over this mental block, here are parts for you: http://www.radioshack.com/product/index.jsp?productId=2049723 They don't matter though because the difference between these parts and other IR phototransistor and IR Leds of the same size is obviously negligible.

David82


OK, here's the answer you want to hear: it will work and it will be effective, and you probably don't need a processor to do it.

Now, what are you going to do about seduction by other environmental sources of IR?
What are the other environmental sources of IR light in an office environment? If they exist, then where is an IR LEd emitter/detector pair that use a spectrum that is not typically found?

AWOL

Quote
What are the other environmental sources of IR light in an office environment?

Well, it's a 150 million kilometres away, but it's a biggie.

Quote
If they exist, then where is an IR LEd emitter/detector pair that use a spectrum that is not typically found?
Illuminators used for IR number plate recognition systems are necessarily heavily filtered to eliminate environmental IR.
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

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