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Author Topic: Index  (Read 841 times)

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Offline MN300

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Re: Index
« Reply #10 on: March 01, 2020, 07:37:27 AM »
There is a diagram in the datasheet.
https://www.ttelectronics.com/TTElectronics/media/ProductFiles/Optoelectronics/Datasheets/OHB900.pdf

Pin 1 is VCC (12V)
Pin2 is Ground
Pin 3 is the output.
You can attach the 10K resistor there. It may not actually be needed if your BOB provides pull up, but it won't hurt.
There is a figure in the datasheet that shows a 820 ohm resistor. This value would be needed to operate at the device's maximum speed. That would be 100,000 rpm with two vanes. I assume you aren't going that fast.

The vane is interrupting a magnet field so it needs to be a ferrous material.
Re: Index
« Reply #11 on: March 01, 2020, 08:31:18 AM »
Thanks MN300.
I have 5v easy available at the mill, can this be used instead of the12v? Vil it cause problems?
The datasheet says that it operates over a broad range of supply voltages (4.5 V to 25V).

Offline MN300

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Re: Index
« Reply #12 on: March 01, 2020, 09:00:57 AM »
Yes, 5V should be fine.
By the way, I made a mistake in converting the maximum switching frequency of 200 KHz to motor speed. It should have been 100,000 revs per second.
Re: Index
« Reply #13 on: March 01, 2020, 09:56:21 AM »
Thanks OK. Mine goes to max 3500 rpm.

Offline MN300

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Re: Index
« Reply #14 on: March 01, 2020, 11:06:55 AM »
My first idea for an alternative was a system we used in the 1990s as an inexpensive and rugged encoder. Sold by Xolox, it consisted of a magnetic wheel with an alternating pattern of north and south poles around the circumference and a hall effect sensor. Unfortunately that company is no longer around.

Today I found equivalent wheels at Digi-Key. I believe the small hole for the shaft can be bored a bit larger if necessary.

4 pole Wheel, equivalent to two vanes
https://www.digikey.com/product-detail/en/phoenix-america/G10-A-0125-25-004/2222-G10-A-0125-25-004-ND/10498946

Hall sensor example,  You can probably find less expensive sensors at a hobby electronics site. There are also sensors in a transistor-like package but those will be harder to mount.
https://www.digikey.com/product-detail/en/standex-meder-electronics/MH21-11S-300W/374-1401-ND/5270608
Re: Index
« Reply #15 on: March 13, 2020, 05:27:28 PM »
I have now received some OPB607A sensors and have wired one as the diagram using R1 = 150 ohm and R2 = 10K ohm. I supply 5v and measured the voltage between earth and "signal out" to 1,3v with no reflector. The sensor do not react to a reflector at all,- no change on the reading.
Have I used wrong resistors, or have I blown the sensor?

Offline MN300

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Re: Index
« Reply #16 on: March 13, 2020, 06:01:59 PM »
Most digital cameras can see infrared so it is easy to see if the emitter is working.

Recheck your wiring, pinout diagram is on sheet 1
https://www.ttelectronics.com/TTElectronics/media/ProductFiles/Optoelectronics/Datasheets/OPB606-607.pdf

pin 1  output, 10K to  +5V  BROWN BLACK ORANGE
pin 2  ground
pin 3  LED emitter, 150 ohms to +5V  BROWN GREEN BROWN
pin 4 ground

https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-resistor-color-code-4-band
Re: Index
« Reply #17 on: March 14, 2020, 06:24:27 AM »
Yes you were right, my wiring was wrong. I have made a new wiring diagram witch I think is correct. Please comment. I have attached the diagram, but have not tried it jet.

Offline MN300

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Re: Index
« Reply #18 on: March 14, 2020, 08:51:56 AM »
Your diagram looks fine.
Re: Index
« Reply #19 on: March 14, 2020, 10:00:22 AM »
OK Thanks.
I tried it connected up, it is working!!!,- but I am getting the following readings: .71v and 1.26v.
What to do? Lover the 10K ohm resistor or the 150 ohm?
Well, I know, I could have tried different resistors but it is easier to ask  :) :)