What can you do with Opto encoder?

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Since mikroeletronika has resumed part of its technical support standard, I also resume introducing their products.

 

Now I find this product interesting, what can we do with it?  Do we need 2 click boards to perform measuring distant, motion, etc.?

 

https://www.mikroe.com/opto-enco...

 

Hope to hear your opinions.  smiley

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Last Edited: Wed. Aug 3, 2022 - 07:05 AM
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HKPhysicist wrote:

what can we do with it? 

 

The same thing we can do with any quadrature encoder: detect relative changes in position of an appropriate scale.

 

Quote:
Do we need 2 click boards to perform measuring distant, motion, etc.?

 

Did you look at the datasheets for both the breakout board and the sensor? Do you understand how quadrature encoders work?

 

In any case, the answer is no, we do not need two boards. But we do need an appropriate scale to put in the slot on the sensor with the right line spacing to match the sensor. Do they sell those at Mikroe? Without the scale the sensor is useless.

 

Brian Fairchild wrote:

It's at this point that we really do need the OP to come back and engage with us. So many questions..........

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Just buy an encoder, the board looks somewhat worthless.

 

You want to mount the opto interrupter where you need to use it..  Use it for a rotating shaft, knob, etc  Or detect a sheet of paper traveling down a path in a copier.

 

Make your own PC mouse wheel.  It's electrically isolated (opto)...so detect a swinging plastic finger on some high voltage equipment.

 

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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eugene the jeep wrote:
But we do need an appropriate scale to put in the slot on the sensor with the right line spacing to match the sensor. Do they sell those at Mikroe? Without the scale the sensor is useless.

 

I cannot see anything on its page mentioning a separate physical scale.  sad

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avrcandies wrote:

Just buy an encoder, the board looks somewhat worthless.

 

You want to mount the opto interrupter where you need to use it..  Use it for a rotating shaft, knob, etc  Or detect a sheet of paper traveling down a path in a copier.

 

Make your own PC mouse wheel.  It's electrically isolated (opto)...so detect a swinging plastic finger on some high voltage equipment.

 

 

ok.  Thank you.  I thought it was a hi-tech new stuff. enlightened

Last Edited: Mon. Aug 1, 2022 - 06:06 PM
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HKPhysicist wrote:

eugene the jeep wrote:
But we do need an appropriate scale to put in the slot on the sensor with the right line spacing to match the sensor. Do they sell those at Mikroe? Without the scale the sensor is useless.

 

I cannot see anything on its page mentioning a separate physical scale.  sad

 

From the Mikroe web page you linked to:

Quote:
Signal encoding itself is done by the host MCU. Having two optical sensing channels, Opto Encoder click has the ability of both speed and direction encoding. The most common usage is encoding of the step motor position: a cylinder with slits is physically mounted above the sensor so that the LED can illuminate the phototransistors only through these slits. By rotating this cylinder, the light beam will be blocked periodically. The single sensor output will be a pulse train, while the cylinder is rotating. Having two photo sensors physically distanced by a small amount, allows the pulse signal of the first sensor to be either delayed or expedited with respect to the pulse on the second sensor, depending on the rotational direction.

 

From the Vishay TCUT1600X01 datasheet:

Quote:
Channel distance (center to center): 0.8 mm

 

That means the slits mentioned in the quote above must be 2*0.8 = 1.6 mm wide and spaced 1.6 mm apart. That's usually called 3.2 mm line spacing in case you want to go looking for a cylinder or linear scale. Wider spacing will still work, though the steps will not be evenly distributed with motion. Narrower spacing may be impossible to decode without errors.

 

Vishay probably intends the sensor to be used in OEM applications where the manufacturer of the product will have a custom scale (cylinder) injection molded with slits and spacing and mounting specific to their product.

 

If you look at products from MicroE (similar name, different spelling, now Celera) you'll see that they sell the sensor and scale as a set.

Brian Fairchild wrote:

It's at this point that we really do need the OP to come back and engage with us. So many questions..........

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There is nothing much to say about this, is is just an opto interrupter that has 2 detectors.  You can interrupt one or both, or buy them with just one detector...there are many varieties.

 

 

When either chan is blocked that signal is reduced.  If you want to make a quadrature encoder then the signal edges must mechanically align properly to form the quadrature pattern.  Some encoders use two separate, concentric rings (shown below)...those may be an interrupter, or a reflective sensor. 

 

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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I don't believe that the company is describing the product correctly.   This board appears to need some kind of slotted wheel to rotate inside of the two "towers" that hold the IRLED on one side and the two phototransistors on the other.

You will find two units like this inside of every old-style mouse (that uses a roller ball) or any trackball.  One unit will be measuring X movement and the other Y movement of the mouse.

 

This is not what we call a "rotary encoder".  A rotary encoder is like a potentiometer, except that it doesn't have physical limits at 0 and 270 degrees of shaft turn.  The encoder shaft can be spun completely around using your fingertips.   This "click" device could be called a "rotation decoder" since it can measure the speed and direction of any slotted wheel positioned in its middle. 

 

A rotary encoder is most often used with a menu display system and a select button.  When the user turns the encoder shaft, the menu display highlights a different item on the menu, When the button is pressed, the application executes the code for the menu selection.  I'm not sure that you use this "click" board for anything.

 

 

Last Edited: Mon. Aug 1, 2022 - 08:16 PM
This reply has been marked as the solution. 
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Here's an example of a similar sensor used on a brushless DC motor. You can see the cylinder which extends down into the slot in the sensor itself.

 

In this case the cylinder is about 18 mm in diameter and has 100 slits and 100 slats. This would be called a 100 line encoder, though the actual resolution is 400 steps per revolution. The distance from one slit to the next is about 0.6 mm (really a little less) so the distance between the photodetectors in the sensor must be 0.6/4 = 0.15 mm. You can see that this requires a scale (cylinder) with finer features than the Vishay sensor with 0.8 mm spacing between photdetectors.

 

Not sure why Mikroe went to the trouble of making the break out board as it needs a cylinder like the one in the photo, whatever diameter you want it to be, but with 1.6 mm slits and 1.6 mm slats. Might be able to make something functional with a decent 3D printer, but just barely.

 

Attachment(s): 

Brian Fairchild wrote:

It's at this point that we really do need the OP to come back and engage with us. So many questions..........

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It may have a mighty low angle resolution. If you can dig up this information, may be interesting.

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Not sure why Mikroe went to the trouble of making the break out board as it needs a cylinder like the one in the photo

Absolutely right!  (or perhaps I'd better say incrementally right! cheeky)   Maybe the board is ok, just to play with opto interruption...you can put some paper or maybe a quarter in there just to experiment and make the boss think you are a winner.

 

There are also MAGNETIC versions...those not affected by build up of grime, grease, dust, flour, molasses etc

 

http://web.sensor-ic.com:8000/ZL...

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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avrcandies wrote:
There are also MAGNETIC versions...those not affected by build up of grime, grease, dust, flour, molasses etc

 

Nor glom of nit... don't ask us about iron filings, or Mrs Cake!

 

Neil

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Perhaps, it can measure a parallel sheet of glass's refractive index?!?  smiley

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Simonetta wrote:

You will find two units like this inside of every old-style mouse (that uses a roller ball) or any trackball.  One unit will be measuring X movement and the other Y movement of the mouse.

or could get from two opto mouse recently.

www.tokopedia.com/madagang .Buy and Donated cheap electronics and manuscripts.

Last Edited: Thu. Aug 4, 2022 - 04:25 AM
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avrcandies wrote:

There is nothing much to say about this, is is just an opto interrupter that has 2 detectors.  You can interrupt one or both, or buy them with just one detector...there are many varieties.

 

When either chan is blocked that signal is reduced.  If you want to make a quadrature encoder then the signal edges must mechanically align properly to form the quadrature pattern.  Some encoders use two separate, concentric rings (shown below)...those may be an interrupter, or a reflective sensor. 

 

 

High-performance industrial automation uses a lot more than two slots in their detectors.   I worked for them for awhile.  But your fundamental point stands - They do quadrature.  Unless you ask for something more (Where's your index track?)