Need help finding a switch

Discussion in 'General Electronics Chat' started by agroom, Jun 15, 2011.

  1. agroom

    Thread Starter Active Member

    Oct 15, 2010
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    I've been pulling my hair out trying to find a specific switch. I'm pretty sure I've searched all of DigiKey and Mouser with no luck, though I don't really know where else to look though either. It may not even exist :(

    Anyway, here's the general specs:

    Type: Slide
    Circuit: SPST or SPDT (though I'll take any if it meets the other criteria)
    Function: On-On, On-Off (again, any if it meets other specs)
    Actuator Type: Standard
    Mounting Type: Panel
    Orientation: Vertical preferred
    Rating: the circuit is supplied by a 6VDC supply and would need to be at least 1A
    Size: ~20mm in length - this is crucial

    Here is a picture of a switch from DigiKey that's about exactly what I need; however, the problem is in it's construction. This switch has the plate on the bottom and is held on by 4 little tabs that fold over. For the application I'm using it, I've tried 4 of these and every one has broken from pulling on the wire and the plate falling off.

    Here is a the construction style I'm looking for. You see the bottom is held in by a different construction making it much more solid.

    The problem is I need a panel mount and one that has the hole not just the U shape. The 2nd one listed above would be perfect if it was a panel mount. It also needs to be metal and not plastic. Also, if anyone knows a way of just reinforcing the first one, that would probably work too. Thanks in advance for any help!
     
  2. #12

    Expert

    Nov 30, 2010
    16,284
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    Stupid idea but, have you thought about fastening the wires so they don't jerk on the switch?
     
  3. someonesdad

    Senior Member

    Jul 7, 2009
    1,585
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    +1, as those slide switches are not designed for a force as you've described it.
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Well, I took a quick look at the Grayhill and C&K website catalogs, and didn't really see anything just like you described.

    Why don't you explain the reason why the wires are pulling the plate off the back of the 1st switch? The switch backing isn't meant to be really physically strong; it's meant to insulate well. The wires should be held in place near the switch in a service loop via a mechanical fastener of some sort; wire clamp with a screw and nut for example, or perhaps Zip-tied to a mount somewhere.

    If the switch is failing, you are exceeding its' mechanical limits. The trick is to stay within the design limits of existing devices.
     
  5. agroom

    Thread Starter Active Member

    Oct 15, 2010
    60
    1
    Here's a link to the project I'm working on, an LED hula hoop. My wife currently has one she bought from a reputable online retailer and the switch in the 2nd photo is the one used in her hoop. The problem is they use hot glue to hold the switch in place which is horribly hard to mount (having the temporarily hold it in place while dripping hot glue 4" down a 3/4" hole) and has failed once and coming lose a 2nd time. If you see later in the album I've come up with a more secure method but requires a surface mount w/ holes.

    What's happening is when the hoop is disconnected to replace the battery, if the user pulls on the wire, even just a little bit too hard, the prongs holding the bottom in aren't strong enough and switch completely falls apart. Not the case though for the 2nd switch.

    #12 might have a good idea, but there's really no where for the wires to secure to. I might be able to secure a wire across the switch so if pulled it would distribute the force back across the wire and not so much on the switch, but the switch is secured solid to the hoop which I believe would still just pull the bottom out again. Really the 2nd switch is pretty solid, I have one that I've tested and it's not coming apart; I just find it hard to believe there's not a surface mount version of it. But if anyone has any ideas, I'm completely open for suggestions.
     
  6. agroom

    Thread Starter Active Member

    Oct 15, 2010
    60
    1
    Note - The setup in the picture is four a double circuit, normally I'll just be making them with a single switch.

    On a side note, if anyone knows of a DP4T switch that would meet the same requirements, I'm all ears! Or at least another setup I could turn on each circuit individually as well as together. So it the 4 positions would be C1-C2-C1&2-Off.
     
  7. PackratKing

    Well-Known Member

    Jul 13, 2008
    850
    215
    run into this problem a couple times.
    a good solution is to solder a piece of say - 24 ga hard copper wire between the tabs holding the bottom phenolic in, clip and file the burr, followed by a coat of "liquid tape"
     
  8. agroom

    Thread Starter Active Member

    Oct 15, 2010
    60
    1
    Yeah, that was kinda my though. It's a real pain to assemble it all only to find out it didn't work, then disassemble it again. If you've had success with this, then I'll likely give it a try. Do you need to do anything special to the tabs or anything? Will the solder adhere to it pretty easily?

    I'm also thinking when I'm done I'll still use the hot glue though. It might coat everything enough so that it can withstand the abuse. Which is probably why the one company used it, they could have ran into the same problem.
     
  9. someonesdad

    Senior Member

    Jul 7, 2009
    1,585
    141
    One technique might be to pot the switch in epoxy. A manufacturer might mold the whole thing in plastic, but you probably don't have facilities for that. This is a good example to show that "electronic" products often have more challenging mechanical/system design issues than the electronics.
     
  10. PackratKing

    Well-Known Member

    Jul 13, 2008
    850
    215
    ........you might want to scuff up the area around the tab, down to brass if it is, and then use plenty of flux, 63-37 alloy, and a good hot iron, that will "spot-solder" instead of having to heat more of the casing than necessary. the switch casings usually take solder quite well.
     
  11. #12

    Expert

    Nov 30, 2010
    16,284
    6,797
    That is why I have a Weller 250 watt soldering gun. It has enough mass and brute force to get a good solder connection on a metal plate FAST...as in, "before something else melts".
     
  12. agroom

    Thread Starter Active Member

    Oct 15, 2010
    60
    1
    I've never done any soldering like that nor do I own a soldering gun like that. Is it pretty easy?

    I guess in the end I'd still rather have a better constructed surface mount switch...anyone else have any ideas where I can look?
     
  13. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
    You keep saying "surface mount" but nothing about your project as built or intended suggests a need for one. Do you mean "panel mount" to provide holes for your rivets?

    There are plenty of stronger switches at the sources previously cited. They will tend to be too big to fit the tubing and the prices will be relatively high.
     
  14. agroom

    Thread Starter Active Member

    Oct 15, 2010
    60
    1
    Sorry, my mistake, yes I do mean panel mount.

    Yeah, most switches that look like they'll work are closer to 35mm in length. It really does baffle me though that there's obviously a through-hole version of what I'm looking for but not a panel mount.

    This seems to be the closes match. The mounts are the U shape and not the hole but since the switch is of the construction I'm looking for I'll see if I can't figure out if it'll rivet to the tubing.

    My 2nd idea, and in conjunction with rivets, is to fill the hole with hot glue once the switch is mounted. This could greatly help reduce any force on the switch. Ideally I'd like to both have a quality switch and use the hot glue.
     
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