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Author Topic: Reference: http://pcbheaven.com/circuitpages/Long_Range_IR_Beam_Break_Detector  (Read 4012 times)

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GS88

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I'm sorry but the long url had not permitted me to use BB codes. Or maybe I'm not able to use it. Sorry again.

I'm working on extending capability of an open source project called photoduino:
http://code.google.com/p/photoduino/wiki/Introduction?tm=6

Photoduino work very fine except for his IR barrier. It has a very short range in dark room about 30 to 40cm. It decrease in bright light to about 12cm. The reason of the short distance IR resides in his design. Only a led with a simple resistor attached.

After working on the code and extending it with some more features, I'm now in the process to provide it with a full useful IR barrier. My goal is to reach at least 3meters (no need to cover more).

So after some research on google I found this project: http://pcbheaven.com/circuitpages/Long_Range_IR_Beam_Break_Detector/?p=0

Unfortunatly I'm not expert in circuit although I'm skilled on the programming language :(

What I would like to ask if someone help me implementing a long range IR barrier. Photoduino has already two ports dedicated to IR barrier where the code reads status changing (called barrier sensor), but I'm not able to make the necessary adjustment.

I think about using the two molex to extend the cable 5meters from the board and then attaching the IR barrier circuit.

But unfortunatly I'm not able to figure out how to do that. Any hints?

Regards.

kam

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i suppose that this photoduino thing is based on an AVR, right? I suggest you don't use my circuit. Instead, get some powerful LEDs Product Review - IR remote Control Jammer and power them from a transistor. One port from arduino will control the base of the transistor. The port will send 38KHz signal to the LED. Then, use a receiver like TSOP1838 which outputs a nice rectangular signal when IR of 38KHz frequency is detected. This simple configuration will give you 10 meters of range or more. It all depends on the IR LED, must be powerful enough.
The reason that i made all this circuit that you reference to, is because i dd not want to use a microcontroller. Since you use one already, the circuit has no real sense.

GS88

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Yes, it uses an Arduino Duemilanove. Could you please explain in more detail something about circuit (RX/TX)?

Thank you so much.

kam

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the circuit is not a big deal. Te output of the arduino will go to the base of a transistor through a resistor (like 1kOhm or less). The collector of the NPN transistor will be at 5 V and the emitter will drive the IR LED, through the appropriate resistor (you must choose a value according to your LEDs).
Then, connect the TSOP (the way i've done in my schematics) and you're done. it is all up to software then.

GS88

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So, your RX circuit is ok? Please don't blame me but I'm not too experienced in electronics.

Thank's a lot.

kam

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no you won't use any of my circuits. your RX circuit will only be the IR LED with the transistor.

GS88

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Any chance to have a schema? I didn't understand what you mean.

I'm sorry.

kam

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again: forget the schematic. you need a transistor, a few resistors an IR LED and an IR receiver. There is no schematic for this.

GS88

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Thank's a lot.

Do you think I can reach at least 3 meters with the explained configuration?

How can I concentrate the flow to catch small thing around 5mm?


kam

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3m? easily! i'm talking about 10 meters or more. For small things, you have to focus the beam. You can put the IR LED in a tube of let's say 5mm internal diameter and 80mm length.