hi
excueme for poor English
this product about needle counting for knitting machine .
it works by reflection of laser light .
any body knows about this or reference for study
thanks

product link:
needle counting

 

According to the site you reference, it reads:

Operation
The optical head projects a narrow spot of light onto the passing needles, which reflect a part of the light. These light pulses are fed to the control unit via fibre-optic cable. The control unit automatically adapts to the needle sequence corresponding to the machine speed and the gauge of the needles. If a pulse has not been received at all or not at the correct position due to a needle defect, the machine control is triggered to stop. Simultaneously with the stop signal, a needle counter begins to work. It indicates the number of needles that have to run past until the optical head reaches the position of the defective needle. For the machine operators this is a valuable support when it comes to locating and to replacing a defective needle. Missing needles can be masked out e.g. when working with cutting line or when producing patterns. To avoid false stops, the number of revolutions before stopping the machine is adjustable.

So it sounds like it's just some kind of fairly basic form of a "slot detection" optical reflection sensor; essentially a bright light (LED probably - maybe a small laser) reflecting off the needles to a phototransistor or photodiode of some nature. There's a bit more to it, of course, in that it uses a fiber optic bundle for the light and sensing (basically just a light pipe with a lens on the end; the actual sensor would likely be inside that box with the counter and control system).

What is the purpose that you need a "reference for study"? Are you wanting to simulate such a device (either physically or virtually)? Are you wanting to build a similar device?

If you need more research, searching on the terms "reflection sensor", or "phototransistor reflection sensing" (substitute "photodiode" for "phototransistor" as desired) should get you somewhere.

Related devices (ie, things that use reflection sensors for light/dark sensing via reflected light) would be things like:

1. Old computer mouse devices (though they typically used "slot sensors" for that - some did use reflection sensors, though).

2. Bar-code wands (pen-shaped devices that had a very small reflection sensor at the tip; these combine the photo-detector element and a usually invisible infra-red LED into one small package; by the way, bar-code wands don't see much use nowadays, but they were popular things back in the 1980s and 90s for scanning items at point-of-sales terminals, and inventory tracking systems, like a library).

3. In a larger form for "safety gating" - where there is a central focused light source and detector mounted across the entrance to a dangerous area, and the light generated is reflected off a mirror placed directly opposite of the sensor, to control machinery and shut things down if someone or something enters the restricted area while the system is operating; something similar is also used for reading bar codes on boxes, or doing other control/counting duties, for items on conveyor belts.

Also - in the case of the sensor system you reference, the company behind it may be using a red light source, instead of the more typical invisible infra-red light source, because the needles may not reflect infra-red light very well; in all such sensors, though, the light sensor and the light source generally share a "peak wavelength" of a similar range, whether the light is visible or not; if they don't, the detector may or may not work as well - or at all. The reflective surface also needs to be such that the reflected light remains visible to the sensor; for instance, with a red-light source and red-light sensitive detector, you wouldn't want to try and read a bar code that is rendered in the color red (instead the more traditional color of black); red boxes, too, may be similarly mis-counted/identified by such a detector as well...

In either case, the "red" used would need to be of a hue that falls within the wavelength of the detector and light source; certain red color hues might be ok, but it would be best to such colors/hues, if possible...or to use a detector/light source with a radically different "peak wavelength" range.

I hope this helps; I have no industry experience in this kind of thing - this is all just based on what I know, and what I have played around with as a hobbyist...

 

Such a needle position verification system that is sensing the reflection from a round needle will be very sensitive to the position of the inspected needle, as well as to the surface finish. For the setup it seems that using a visible laser beam is the only sensible choice, allowing a skilled technician to achieve an adequate alignment. Given the speed that such machines run, the response time for the sensor must be very rapid. My evaluation is that based on my experience with small-beam red lasers is that their output does certainly decline after many hours of use.
So now my question: Just what does the TS (Thread Starter) need to learn??

 

thanks a lot

I want to design this system and please help me to find out about sensor and idea about sensor circuit

for start I have IS0203 and PD438C sensor and 5mw laser
laser module link:
5mw laser

 

Oh Wow!!! Design a similar system. THAT is quite a lot different from understanding the system well enough to keep it operating. Consider that both the mechanical aspects and the electronics aspects are rather demanding, in addition to the fact that it will include quite a bit of software. While you can see the laser beam in the video reflecting off of each needle as they pass by, you do not see the sensor detecting that the reflection is in exactly the correct position. So what looks like just a piece of solid tube with the laser beam coming out the end is actually a bundle of fiber optic s inside. Back in the housing are both a laser light source and a very fast, very sensitive, light detector. The laser drive needs to be regulated so that the intensity will be constant, and the sensor needs to be both very fast and very stable, because it needs to verify not only that the intensity is correct, but also that the location is correct. Probably that information needs to be held along with which position the needle is in, which would probably require an encoder input of some kind. So this is not a simple project, because every bit of it will need to be assembled in a manner qualified for industrial machinery. That is the sort of things that I used to do. It requires a fair amount of resources to create an adequate design.

 

hi
I received laser beam reflection by PD438C
photodiode in dark room voltage was 2v.

when beam reflected from needle hook voltage drop to 0.8v when bend needle a little voltage was 1.5v after repeat get the same result.

so now I want to code laser beam and receive by sensor and decode it . may I use ir remote library ?

do you have any idea for measuring signal amplitude to detect needle state ?

 

Consider that the motion in the knitting machine is very rapid and so the response to the reflection must be extremely fast and accurate, as well as being timed very precisely.
Isyour goal to duplicate the function of the system shown in that link?? THAT will be quite difficult.

 

REally, it will need to be synchronized to the rotation and compare the signal from the sensor accurately to what the signal should be for that position. That will require some fast electronics and a very fast A/D converter.AND a very stable computer. There will not be any microsopht products involved with the system.