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  Sorry, Staigen. I'm an electronic newbies. Can any expert or non expert help me to solve my problem because I'm do not have any idea? Do you have any tutorial or good webpage to intro to me. My question is as below:-

Hi! I need to use an infrared diode to calculate the number of coins drop, may I know what type of infrared diode is suitable? I also need to do use a motor to vibrate the coins to make it fall down the slope, may I know what kind of motor can I use?

  Thank you first for your kind help.  :)

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You can use any type of LED, not only IR but a regular one as well, in case that the device is in dark. You can place ANY led on one side of the "tube" you r ysing for the coins, and a light sensitive cell on the other side, and it'll work ok.
A suitable motor: you may buy or get an old cell-phone. Inside you'll find a tiny motor - the vibrating one. You may buy one at any "cell-phone" store.

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As Tedyp said, you don't have to limit yourself to IR if the interior of the coin drop area is adequately shielded from exterior light, although IR would work fine.

Do you have to detect coins of many sizes, or just one size?  If one size, then a simple opto-interrupter module should work fine.  If many sizes, the opto-interrupter could still work if you can guide the coins of all sizes to pass between the emmitter and detector arms, which ought to be easy.  If you can use an opto-interrupter, you have very many choices of models, wavelengths, and configurations and many makers can provide application notes for their products.  With an opto-interrupter, the emitter and detector are automatically matched and aligned, which simplifies the design.  Also, unless the opto-interrupter is very brightly illuminated with stray light, it will probably not be bothered by ambient light because the emitter and detector are optimally oriented toward each other and are somewhat shielded by the post supporting the opposing device.

Almost any small motor with an eccentric weight on the shaft should do the trick.  Without knowing something about how heavy an assembly the motor must shake it is not possible to give a specific recommendation.  But a little experimentation with smaller and larger motors designed to be powered with whatever voltage you have available in your machine should do the trick.


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  • 5 weeks later...

microzone, an opto-interrupter is simply a matched pair of light emitter and detector facing each other in a plastic molding that provides a slot through which an opaque object can pass to block or "interrupt" the light path from emitter to detector.  Just think of it as a matched pair emitter and detector that the manufacturer has mounted for you to make it unnecessary for you to provide the optimum mounting arrangement to detect objects passing between the pair.

Go to www.digikey.com and search for "optical sensors, then "interrupters."

Or go to www.mouser.com and search "photo-interrupter."

You could also probably use a reflective sensor which has the emitter and detector side-by-side "looking" in the same direction, away from the module.  This configuration detects a reflective object passing in front of the module.  However, if you can use it, I think the interrupter type would offer more reliable sensing because it does not rely on the reflectivity of the object, just its opacity, while the reflective sensor depends upon the location and reflectivity of the object being detected.

These devices come in a great variety of wavelengths and physical and electronic configurations from simple bare-bones units with emitter and detector leads hanging out to amplified units, photo-darlingtons, photo-SCRs, photo-Triacs, etc., etc.  Start out by finding a unit that looks like it fulfils your physical requirements then download the data sheets and application notes and see how they work and how to wire them up.

You haven't given us any info on which to base a recommendation of a vibrator, but go to www.allelectronics.com and search "DCM."  DCM is their prefix for DC Motor-xxx part numbers in their catalog.  (All Electronics is a surplus store in the Los Angeles area.)  They list several tiny vibrator motors intended for use inside pagers and phones, just the types of vibrators you would obtain by disemboweling a phone as suggested by Tedyp.

These are simply small DC motors with eccentric weights on their shafts.  If you need more vibratory power than these tiny devices provide (as I suspect you will if you are trying to shake a mechanism rather than a shirt pocket), you can "roll your own" by buying a larger motor and a gear or pulley that fits the shaft and sawing off part of the gear to create an eccentric weight.  Try also www.candhsales.com, another surplus store, this one located in Pasadena.  They have lots of motors, gears, and pulleys.  The amount of "shake" you can generate by this means is limited only by the size of motor you buy and the eccentric mass.

Have fun.


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