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Optical rotary absolute encoder project.

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  • #16
    ".so you can understand we do not want any plastic anemometers on the building."

    You could always get creative and modify the basic vane with a wooden made replacement.
    Just use the bearings and sensor and disguise, replace or remodel the plastic vane itself.?

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    • #17
      That off-centre disc thing with LEDs is rather neat. Perhaps a use for other things like CNC screwcutting wanting to know the mandrel position.
      Another commercial hobby weather system uses a non-equal anenometer cup. The one bigger cup makes it move faster on the downwind leg and slower upwind. By meauring the speed variation (wrt a reference trigger) it can work out where the change from acceleraton to deceleration occurs.
      Way back in about 1982 Ciarcia in Byte magazine had a system of a triangle of ultrasonic wind speed measurements that then calculated the direction aswell. All the code was only a few hundred bytes for an 8085 or Z80. Probably take a modern geek 5 megabyte of Python to do it. He also had it broadcast the weather results on medium wave using a voice synth chip so he could hear it in the car as he drove home.

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      • #18
        Originally posted by mickeyf View Post
        The one at AliExpress says "Cannot ship to Canada". First time I've seen that at AliExpress. Amazon Canada has what looks like the identical one, but at about 3 times the price!
        The one I found on AliExpress ships to Canada, it is US$40.00 very simple to modify.or 'Antique'
        Attached Files

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        • #19
          The one I found on AliExpress ships to Canada, it is US$40.00 very simple to modify.or 'Antique'
          I was referring to the hall sensor that MattiJ linked to, not the anemometer. I don't need an anemometer right now but the idea of the 360 degree hall sensor is intriguing.
          "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

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          • #20
            Thanks for all the comments...

            I am not looking at anything other than the units I have already made. The wind vane is in the traditional form and mounts on a steel mast along with the wind speed device. The speed unit has three stainless steel cups and spins in the horizontal plane, the sensor is an optical sensor and interrupter vane.

            I am confident the Hall effect sensor will be perfect for the job and all I have to do is turn up the suitable mount for it with will be inside an extension to the steel mast.

            The displays have been made and are integrated with the Arduino. The bezels are 3D printed to look just like original 'Munro' instruments.

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            • #21
              If by triangle of measurements you mean three sensors aimed at 120° intervals, I would think that two sensors aimed at a 90° angle to each other and both capable of bi-directional measurements would make the math and therefore the computer code much simpler.

              And there are computer code writers who can and do write compact code. They work with the PIC style devices where memory is usually very limited.



              Originally posted by Baz View Post
              That off-centre disc thing with LEDs is rather neat. Perhaps a use for other things like CNC screwcutting wanting to know the mandrel position.
              Another commercial hobby weather system uses a non-equal anenometer cup. The one bigger cup makes it move faster on the downwind leg and slower upwind. By meauring the speed variation (wrt a reference trigger) it can work out where the change from acceleraton to deceleration occurs.
              Way back in about 1982 Ciarcia in Byte magazine had a system of a triangle of ultrasonic wind speed measurements that then calculated the direction aswell. All the code was only a few hundred bytes for an 8085 or Z80. Probably take a modern geek 5 megabyte of Python to do it. He also had it broadcast the weather results on medium wave using a voice synth chip so he could hear it in the car as he drove home.
              Paul A.
              SE Texas

              And if you look REAL close at an analog signal,
              You will find that it has discrete steps.

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              • #22
                I might suggest a AS5134 magnetic encoder or another from their series. The AS5134 has
                360degrees contactless angular position encoding
                Two digital 360 step (8.5 bit) absolute outputs: Serial interface and Pulse width modulated (PWM) output
                User programmable zero position and sensitivity
                Incremental Outputs ABI Quadrature: 90 ppr, step direction: 180ppr, fixed pulse width 360ppr

                Basically you mount a magnet on the end of a shaft, put the IC close to it on the end of the shaft. I have used it with a arduino and there is some sample code out there. I liked it because in my application needed to zero the counter ,measure 360 degrees and count multiple rotations.

                https://ams.com/AS5134
                Last edited by Frugalguido; 02-21-2021, 01:27 PM.

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                • #23
                  Would have thought a pulse pot would suffice?
                  mark

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                  • #24
                    Hmm, I don't know what a 'pulse pot' is.

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                    • #25
                      Rotary pulse encoder, looks like a pot but instead of variable voltage it produces pulsed output, beloved of LG and Samsung washing machines as you turn the pot the program advances to the next or last depending on rotation and you can spin it all day, I’m sure some arduino experts can provide the next, they use them on cnc pendants for table drive too
                      i thought of it as I was just repairing (unsuccessful) my washer, it has a big one on the front
                      mark

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                      • #26
                        Well yes, rotary encoders come in various types and sizes. I might have been able to use one of those and I might have been able to use one of Frugalguido's magnet encoders but the reality is that I now have a Hall effect rotary absolute encoder which arrived in a nicely machined aluminium enclosure so I will use that.

                        Thanks for all the interested comments.
                        John

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