ok, btw, to im not good in PIC, hence i am using 2 555 to limit the pulses....
does anyone know of any IR module that are active high and receives continuous pulse?
the only one i found is SFH 5510-38.but its not available in my place/area.
I am looking to build this circuit for similar reasons. I need to know how to pulse the ir without the use of the pic, or is that the only way? I need only to send a beam of ir energy (10-20 feet) that, when broken, pulses a signal relay.
Also, could a laser be pulsed at a freq. that a reciever would "see" and reduce interference?
We were talking about using a TSOPxxx IR receiver IC and an IR transmitter made with two oscillators. One oscillator is at 38kHz and the other oscillator causes the 38kHz to be in bursts. Two 555 oscillators can do it easily.
Most TV remotes use this method and the range is at least 10m.
You are talking about using a laser which is not IR and which probably won't be received very well by an IR receiver IC.
Uncle $crooge
Originally Posted by audioguru
Oddly enough, I did a similar experiment earlier today. I made an IR proximity alarm (first microcontroller project). I get about foot range, but it triggers every time I use a remote control. So, I wired up a laser pointer on the breadboard I used to develope the project, in place of the IR emitter. It triggered the PCB version. Took everything outside, set the alarm on the back fence, triggered it from my porch about 60 feet away.
Point of the experiment was to see if the IR module would work from a laser pointer, laser trip-wire project I've been thinking about. Need to wire something up and see if the module can handle continous 38kHz pulses, as I have had no luck turning it on and off in my program (want to reduce battery consumption...).
I see ..... what freq. should the second oscillator be tuned to? I am getting my order together.
Harvey, what type of reciever was it that you used? Was it an IR or ?
Did you try it in the sun or shade?
The datasheet says 1400Hz max, but if your square-wave isn't square then use a lower frequency maybe 500Hz. This second oscillator should gate the 38kHz by connecting its output to a voltage divider at the reset pin of the 38kHz oscillator.
Uncle $crooge
Its an IR module, and the sun was just starting to rise, so mostly dark. Can't see a laser pointer very far in daylight.
I have a laser that you get at one of those "chain stores that sell everything" and I can see it well in the day light. The neighbors house is easily 60-75 feet away and I can see is against their outside wall. You do need some kind of large flat surface to locate it and aiming is tough at that distance.
What about modulating both the laser and the IR led? The laser would be useful to aim with.
Im going to try that with mine. Im waiting on parts now anyway!
You can pulse the laser at 38 kHz and it will trigger the IR-Reciever-Module directly. The laser isn't as bright at 38 kHz, it's only on half the time. I did run the output from the MCU through a transistor to see if higher current would help, but its been kind wet and rainy lately. Does seem slightly brighter, but not as much as I hoped.
The case of a TSOP1738 IR receiver IC is black and blocks visible light very well. I know a red laser is very bright but look at this graph and try to determine how little of the red light will be detected.
Uncle $crooge
Don't have a part number on the reciever module, but it works. Having a rainy chrismas, figured I'd mess with it a little further. Wanted to bounce the laser off a mirror, total pain in the ass to line up that way. Have to figure out something. Had some camera mounts with ball swivels, but no idea where I put them...
Hi HarvyH42,
To incerase the range, i understand that we have to tune the IR TX (555 frequency to be close ly equal to to IR Rx and only then the range will increase,
Reg arranging mirrors, i feel it may be possible by first looking with a red Laser torch (used as pointer in presentations.) you may perhaps initially arrange mirrors by using stick gum from your hall to another room and to a third room from there.
After being able to align with red laser troch and the final point can be substtuted with TSOP Rx and the torch by IR Tx perhaps, sir
Also, you may be able to park your car away and use its View finder mirror to reflect the signal back. of course you have to temporarily substitute by sticker , a flat mirror across it and orient it to reflect you signal back to a wanted point. however a visible red laser light is purposeful, sir
regards
Last edited by mvs sarma; 27th December 2006 at 09:41 AM.
Regards,
Sarma.
It was just quick experiment to see whar kind of distance. Didn't really think lining up a tiny dot on a small target would be such a pain. Need to make something that will do very fine adjustments and not move around. Got a few ideas with a ball joint, couple of screws and springs. Just no spare time to build lately. Hopefully after the holidays.
A little advise - think BIG, think STRONG, think HEAVY - it mustn't move at all!, and the greater the distance the more solid it must be.
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk
Ive got the tsop32238 pn the bread board. Can I plug it into a comparator to get it to energize a small signal relay or will it have to go through a pic? I tried a transistor with no luck.
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