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Solenoid Driver Circuit Without Using Arduino

Discussion in 'General Electronics Discussion' started by Mike Lansing, Jan 7, 2019.

  1. Mike Lansing

    Mike Lansing

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    Oct 7, 2017
    Bob Pease page on 12 v solenoid driver circuits seems to be a good model.

    What's All This Solenoid Driver Circuit Stuff, Anyhow?
    [Mod edit: dysfunctional link removed. Correct link see next post]

    Working with multiple Uxcell 4.5V open frame linear mini push-pull type solenoids at 40g/2mm, the question arises as to how one can calculate the Pease circuit for adaption to the 4.5 Uxcells (from Amazon). Having yet to calculate the resistance of the Uxcell coil, should not Pease's circuit be applicable for use of multiple Uxcells such as these? The plan is to power the Uxcells with AA batteries for portability.
     
    Last edited by a moderator: Jan 8, 2019
  2. Alec_t

    Alec_t

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    Jul 7, 2015
    You would also need to know the minimum pull-in voltage and the drop-out voltage to calculate the optimum resistor value.
    Can you post a link to the solenoid datasheet?
    Do 'push' and 'pull' require opposite polarity energisations?
     
    Last edited: Jan 7, 2019
  3. Mike Lansing

    Mike Lansing

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    Oct 7, 2017
    There does not seem to be a data sheet for it at Amazon, and it's a ridiculously complex URL to transcribe onto this thread. The Amazon page says: 'Uxcell a14092600ux0438....' Once calculations are more clear, it should be no problem to divide up the AA battery banks, for instance, if there are theoretically no more than 8 or 10 solenoids that will be operating simultaneously, though there may be 40 or so solenoids in all to choose from. A more rigorous search for the data sheet, then. Activation requires only one polarity energisation, it returns via a spring. Because this is a musical application, Pease's multiple-solenoid circuit will be put to the test, especially his expert forethought about switching speed.
     
  4. Alec_t

    Alec_t

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    Before investing a lot of cash in all those solenoids I'd be inclined to test just one with the Pease circuit to see if it behaves as you'd like. If the solenoid 'bottoms out' when it pulls in at full current, there's a good chance it will stay like that with reduced current. If, however, it doesn't bottom out but merely moves a distance proportional to the coil current when energised, then the Pease circuit won't keep the solenoid pulled in very far.
     
  5. Mike Lansing

    Mike Lansing

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    Oct 7, 2017
    Comments on this solenoid state that it's weak, though I think 40g can operate the membrane switch. It would be desirable to understand the equations from the start rather than opt for being a purchasing agent. However, 20 of these have already been purchased, so I'll tend to deal with the cards that have been dealt. Their small size is almost mandatory for my application, they must set one next to the other down the line of membrane switches. In addition, there is also a way to eliminate the need for 20 more solenoids by creating a purely mechanical switching situation that uncouples the first 20 yet uses the same movement to connect to the 20 others.

    Things have changed since I built an electric saxophone in 1987. The Prophet 600 did not have the two-way, time-dependent switches found in today's synthesizers, and this application is also for performance. In a nutshell, MIDI woodwind controllers such as those by EWI and Roland, still do not free the woodwind prisoners so that they can explore the world of chord making from what they already know on their instrument, be it a clarinet, oboe, basson, flute or sax. This situation can change by operating the switching logic of the solenoids in a way that splits the left and right hands so that a melody can be played with the left and chords played with the right hand, the reverse of typical piano playing. EWI has not only removed some of the keys from the original invention of the saxophone, but also has presented the most ridiculous fingering charts based on this. Selmer Corporation knew very well in 1987 that a saxophone could control a synthesizer. This alternative approach also frees the musician for talking, not talking, or even singing while still playing their instrument, which is connected to the synthesizer, a capability piano and guitar players have always had. Apparently, neither Roland nor EWI have done much thinking about the evolution of woodwinds nor the freeing of the prisoners doomed to a one-note-at-a-time existence. When we press on to encompass the Land Down Under, the didgeridoo with a switching harness slipped onto it without marring the surface of the instrument, opens a creative trajectory for the player to experiment with bass line and rhythms from the didj in synch with their synthesizer performance, such as "Fingers" McCullen does with his guitar-didj combination (Youtube).

    If the testing of gram-power on the membrane switch is first desired, is it not a question of safely operating a test solenoid from a AA battery circuit to confirm that it is strong enough?
     
  6. Alec_t

    Alec_t

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    Jul 7, 2015
    Certainly worth doing that test. Try the solenoid first with 3 A cells in series (definitely should pull in, as per spec), then 2 cells, then 1 and report back.
     
  7. Mike Lansing

    Mike Lansing

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    Oct 7, 2017
    Before I knew of your suggestion of three AAs, I first tried a single AA cell and the solenoid worked, though after some repetitions, it stopped working altogether. It can work with 3 AA's in series, though the force test has not been done on the actual switches because of concern for the safety of the raw connection, as well as electromagnetic interference too close to the brains of the synthesizer. In '87 indeed the entire control panel of the Prophet 600 lit up when in proximity to a bank of 12v solenoids powered from a car battery. Should there not at least be a resistor-flyback diode incorporated into the first force-test circuit?
     
  8. Alec_t

    Alec_t

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    That's encouraging, providing it exerts enough force.
    Presumably the battery faded.
    Definitely should be present.
     
  9. Mike Lansing

    Mike Lansing

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    Oct 7, 2017
    Last night, one AA pulled in the solenoid with enough g's to activate the switch. A measurement shows the Uxcell coil at about 6 ohms. The plunger of the solenoid is separated from the two parts of the switch by a small piece of popsicle stick and the solenoid itself is wrapped onto another stick with duct tape, all of which does seem to suppress the electromagnetics. For anyone who is interested, I find that a small bolt through the mounting popsicle stick can have a washer attached so that it moves vertically on a slotted mounting frame, can rotate to exactly align the surface of both parts of the switch, and also horizontally adjusts the alignment. This simplicity gives fine-tuning the ornery touch-sensitive switches six axes of control.
     
  10. Alec_t

    Alec_t

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    In that case 3 AAs (4.5V nominal) should pull it in with 12Ω in series. Rather than 12Ω I'd try the Pease circuit with 10Ω as the bypassed resistor, to allow some margin.
     
  11. Mike Lansing

    Mike Lansing

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    Oct 7, 2017
    Since not having done much about this problem since 1987, there's need to find out about sources for components for this circuit as well as much review of the basics, such as perhaps up to 6, 8 or more solenoids being on at the same time, when to split the battery banks, etc. Thanks for the replies.
     
  12. Alec_t

    Alec_t

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    Jul 7, 2015
    Since each solenoid will be drawing around 1/4 Amp (you might get away with less, using a >12Ω bypassed resistor), 6 or more on simultaneosly will put a big load on those poor little AA cells. Their life will be short and sweet.
    As for the Pease circuit, all components should be readily available from most electronics parts suppliers.
     
  13. Mike Lansing

    Mike Lansing

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    Oct 7, 2017
    Thanks for your reply. It was hoped that solar powered AAs would eventually be incorporated, and these placed in banks to accommodate solenoids 1-6, another bank for 7-13, etc, which now seems problematic because when a chord is played, it is often held for some time, so the Pease circuit's 'hold in' conservation seems critical. An average estimate is ~four solenoids for chord production and one-at-a-time for melody line. Ideally, there would be a power source that will appeal to the solar/wind-minded musician without having to constantly recharge or buy AAs. The rechargeables could drop out instantly during a performance, and limit the time of the performance.

    Even though connecting woodwinds to synthesizer (or any piano keyboard) can be accomplished purely mechanically, the electronics approach introduces the average woodwind player (and whomever else) to interesting experimentation that can expand their knowledge and perspective. The didgeridoo harness is an example that is much more applicable to electronics (including solar/wind recharge) than a mechanical apparatus. We see no reason why the wires leading from a sax or didj to the synth could not be as small as 30AWG.
     
  14. Alec_t

    Alec_t

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    I can't see 30AWG surviving the typical rough handling it would get on stage :).
     
  15. Mike Lansing

    Mike Lansing

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    Oct 7, 2017
    Thanks for your concern. The wiring must be wrapped from the point of attachment at the instrument, to the synthesizer. I chose 30AWG so as to get used to working under magnification, which may be helpful for the quality of the finished switch at the instrument end: the desire to keep the switches discretely out of the way, which is still in the design stage. The first switches of 1987 were much too crude and as well, there was switch bounce let alone the spectre of corrosion coming from a wind instrument. A newer design will have bare metal contacts that confront each other on an oblique plane, not only to decrease contact noise, but to eliminate switch bounce. Both contacts will wear somewhat, though this should eliminate switch bounce and the tendency to corrosion.

    Another aspect of the wiring is that there will also be a change in the way a saxophone has been played, via the use of a neck strap. That will be eliminated, which will eliminate the traditional stress on neck and shoulder muscles. The horn will be mounted on a stand which swivels, somewhat like a universal ball mounting whose tension can decide freedom of movement. The player simply walks up to the instrument to play it. The wiring harness from the instrument does not have to be very long to reach the keyboard which unplugs at both ends but definitely should be reinforced.

    So, I take it that the Uxcell solenoid at 4.5V, 6 ohms resistance, and 1/4 amp align with the fundamental electronics equation fairly well?
     
  16. Alec_t

    Alec_t

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    Not sure what you mean. I was considering 1.5V and 6Ω and using Ohm's Law. 4.5V would require a series resistor of 12Ω to give 1/4A. But that 1/4A is the already-determined minimum pull-in current; the drop-out current (which you have yet to determine) will be less.
     
  17. Mike Lansing

    Mike Lansing

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    Oct 7, 2017
    Are the Uxcell parameters an equivalent ratio of values to the Pease circuit? Or cannot that be determined yet because the drop-out current is unknown? I am trying to understand the physics (as Pease and yourself) of drop-out current, flyback, etc. I can check some "ratios" via a calculator, which should help somewhat, though is not sufficient.
     
  18. Alec_t

    Alec_t

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    Jul 7, 2015
    I doubt it. I don't think scaling the values for one solenoid would give you anywhere near accurate pull-in/drop-out values for a different solenoid, because of different geometries, spring constants etc.
    If you have some resistors in, say, the 3-30 Ohm range and able to handle 1/4A you could try one or more in series with the solenoid, bypass it with a switch when applying one AA cell to get the solenoid to pull in, then open the switch to see if the solenoid drops out.
     
    Last edited: Jan 12, 2019
    BobK likes this.
  19. Mike Lansing

    Mike Lansing

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    Oct 7, 2017
    Thanks for the reply. There are reasons, then, for bringing an actual electronics engineering student (or more students) into this project, not only for my learning curve.

    Having picked up an electronics book found on a free bench in the U.S., Fundamentals of Electric Circuits, the front cover states, 'This International Student Edition is for use outside the U.S.' The back cover states, 'This book cannot be re-exported from the country to which it is sold by McGraw-Hill. The International Edition is not available in North America.' Yet, here it is in all its smuggled glory. The book introduces one to the second most important person for circuit analysis besides Ohm: Kirchoff. Ironically, one of the editors attended Cleveland State University. So, to hunt down an inexpensive assortment of resistors that can handle the amperage and try the bypass approach.

    What are the prospects of wind/solar recharging of a solenoid driver circuit? The idea of not only changing the way music is played but also read, should appeal to the younger student that may also be interested in wind/solar recharging and its electronics. I cannot say that it was my idea, I did not learn that experiments in amino acid music were already underway in 2007 until late last year. The difference is that my approach uses the isoelectric points of amino acids with which to assign to the keys of a saxophone (there are basically twenty keys just as there are twenty aminos.) About nine attributes of amino acids had to be eliminated before choosing isoelectric, because only the latter provides a different pH number for each amino, making it unique, reminiscent of the Coulomb (hydrogen atoms vs electrons). Then it was noticed that one could eliminate four lines of the traditional musical staff and only use one line. The octave key of the horn dictates whether the note to be played is below or above the line, timing values being arranged using other symbols. The idea is to try to eliminate music-reading eye strain and we are definitely keeping dyslexics and others with reading problems in mind with this approach. The notes played, like some synthesizers, can show up on a home-made screen, rendering a transcription of the amino acid sequence. This may help when studying a certain sequence, for example, a cancer gene. In fact, the first sequence we tried to learn was one from around position 1047 of the PI3K gene in ovarian cancer. This position has a mutation from histidine (H) to arginine (R), moving the pH to the highest of all amino acids on the pH scale. We think that this pH direction for mutations can be further explored. When we attempted to apply an ominous-sounding chord where the mutation occurs, it was found that the sequence itself has an ominous sound. Stranger than fiction. As far as is known, no amino acid music example yet gives the listener the original sequence as Nature wrote it without adding other music into it. There is also the prospect of wave energy conversion, to recharge, though an electric didgeridoo without solar recharge seems like a regression. Some of today's synths only use six AAs.
     
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