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Digital counting system for coil winding jig

Discussion in 'General Electronics Discussion' started by kong, Dec 23, 2013.

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  1. kong

    kong

    122
    2
    Sep 26, 2010
    I've built a prototype of a coil winding jig and I want to be able to count the number of turns.

    At first I considered a mechanical counter but decided it would not be feasible.

    I wanted to get someone's opinion on my new idea

    I want to use a laser diode and a photocell circuit. On the end of the motor is connected a small disc with a hole near the rim. On the other side of the hole is a photocell. The laser is focused to the hole. As the motor turns, spinning the disc and bobbin, the wire is wrapped around it and the photocell circuit outputs a pulse to a decade counter/7 segment display counter every time the bobbin makes a complete turn and the light from the laser hits the photocell, which forms a voltage divider with a resistor and connects to the base of a standard NPN transistor. This outputs a 'low signal' to a 555 timer wired in a schmitt trigger configuration. This would then output a 'high' signal and that would be sent to a clock of a 4510 and 4511 driving 7 segments *4.

    Is this a good design?

    Would appreciate any feedback or any advice
     
  2. jpanhalt

    jpanhalt

    426
    4
    Nov 12, 2013
    Here's what I did with a Hall sensor:

    counter.png

    Your beam break input should also work. The Hall sensor might be simpler and less subject to interference ambient light sources. I don't see why you need a laser. An LED or IRED should also work.

    As for the circuit you propose to use, please post a schematic. It takes a lot of words to describe a simple picture.

    John
     
  3. Harald Kapp

    Harald Kapp Moderator Moderator

    11,133
    2,539
    Nov 17, 2011
    You can buy this as a unit, e.g. like this one. The advantage is that the optical components are mechanically fixed and adjusted to give a clear signal.
    This kind of sensor is used e.g. as limit switch in printers, maybe you can salvage one from a defect unit.
     
  4. kong

    kong

    122
    2
    Sep 26, 2010
    The initial reason I wanted to use a laser was to "knock out" all ambient light by using a very focused bright light, and I have one in the project box, although now that you mention it a super bright white LED would probably work just as well and be easier to calibrate.

    I have access to a dumpster where printers are thrown away regularly, I'll keep my eye out.

    Thanks for the info on the pre-built unit, I'm thinking I'll give this a go first then see where I'm at.

    I'm in the very early stages and don't even have a full schemtaic, at this point it was mostly in the mental stage.

    I'll post what I've been working on.
     
  5. kong

    kong

    122
    2
    Sep 26, 2010
    I used the inverting buffer at the bottom of this page:
    http://electronicsclub.info/555timer.htm

    And the display/counter. This is the site I'm using for reference:

    http://www.doctronics.co.uk/4511.htm The schematic is about halfway down the page.

    Basically using this *4. Input is from laser circuit.

    Otherwise there is just a voltage divider to process the signal.

    That's it so far. Thanks for the feedback. I figure simple is better, my brain has a tendency to over-complicate things.
     
    Last edited: Dec 23, 2013
  6. kong

    kong

    122
    2
    Sep 26, 2010
    Oh, also the display/counter. Whoops. This is the site I'm using for reference:

    http://www.doctronics.co.uk/4511.htm The schematic is about halfway down the page.

    Basically using this *4. Input is from laser circuit.
     
  7. jpanhalt

    jpanhalt

    426
    4
    Nov 12, 2013
    That is a lot of components for what could easily be done with a 12F509 or 12F6xx microcontroller and a serial 2X16 display from Parallax, Sparkfun, or others. Of course, if you like to solder...

    How many coils a day do you intend to use this device for?

    John
     
  8. duke37

    duke37

    5,364
    769
    Jan 9, 2011
    I use stone age technology, a magnet, reed switch and electro-mechanical counter.
     
  9. jpanhalt

    jpanhalt

    426
    4
    Nov 12, 2013
    My counter is also electromechanical and was free. I kind of like the soothing sound of the click,click,click...

    John
     
  10. kong

    kong

    122
    2
    Sep 26, 2010
    I like it duke37.

    I have an electromechanical counter. Problem is it doesn't have a 'reset' switch.
    So I would probably end up using a frequency divider and a transistor/relay setup to relatively quickly reset it (by cycling through the count) and that would be a terrible pain. The clicking is nice, though.

    It's just a general coil winding machine for HV mostly. Still in the testing phases. I probably wouldn't use it that often.

    I would use a microcontroller but unfortunately I live in the logic world and I would have to learn how to write code and buy a arduino/or special chip. In this case I have all the parts in my box and am familiar with the logic used.

    Thanks for all the advice, I'll be finishing it up hopefully soon. If it's timely I'll post something.
     
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