A small-sized push button style switch without feedback

Discussion in 'General Electronics Chat' started by munuainen, Jun 13, 2014.

  1. munuainen

    Thread Starter New Member

    Jun 13, 2014
    11
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    Hi, I'm having trouble finding a source for a small push button switch (height from top of the button to the bottom of the casing max 5mm) that does not have push force resistance of the magnitude that's typical to switches with clicking feedback. The switch should be of NO type, and a single switching contact is fine. It would be a huge benefit if the switching occurred already somewhere in the middle of the button motion range, ie. not having to press the button all the way down to make the contact.

    I found a candidate in an old floppy disk drive that fits all requirements other than it's unfortunately NC :( I've googled and searched eBay but can't seem to find what I'm looking for.
     
  2. inwo

    Well-Known Member

    Nov 7, 2013
    2,433
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    What else can you tell us about the application?

    Is there more room surrounding the switch point?

    Can it be open, like a leaf switch?
    I've seen open leaf switches with the parts soldered to pads that take up very little vertical space.

    Is there room for a reed switch under the board?
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,494
    2,364
  4. RichardO

    Well-Known Member

    May 4, 2013
    1,228
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    You may want to look at "detector" switches. Some of them can be quit small:

    http://www.mouser.com/Search/Refine.aspx?N=254111

    As an example, I have used the Alps SPVL110100. Very small and very light pressure to activate. It is surface mount and horizontal orientation so it will probably not work for you...
     
  5. alfacliff

    Well-Known Member

    Dec 13, 2013
    2,449
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    is it surface mount? if it is, look under tactile switches inthe digikey or mouser catalogs. they have non tactile switches too.
     
  6. munuainen

    Thread Starter New Member

    Jun 13, 2014
    11
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    Oh yes. Please see the attached photo for reference. It's a desktop computer front panel audio dongle that has its 3.5mm 5-pin jacks gone bad. The problem is that the only audio jack standard you can find replacements to is AC97 whereas the dongle in question needs Intel HD Audio type connectors. The difference is depicted in the attached image. There's also a photo of my attempt at adding NO isolated switches to open ended AC97 jacks using regular tactile switches that would be pushed by the inserted 3.5mm headphone or speaker plug tip. It doesn't really work too well because the switches need to be pushed down all the way to ensure a reliable connection. Doing so results in too much counter force to the plug, pushing it backwards just enough to then break the switch connection.
     
  7. inwo

    Well-Known Member

    Nov 7, 2013
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    If that's the case, then the 5mm might not include the actuator rod.

    A small actuator could fit inside the "jack" space.

    This information will also limit options to passive switches? No power available.
     
  8. cork_ie

    Member

    Oct 8, 2011
    348
    58
    I seem to remember having a similar problem. Eventually it turned out that the HDA standard does not require that switch and the insertion of a headphones in the front panel is detected by the sound card due to a change in impedance. Turned out to be the incorrect drivers for the Intel board (Sound card was integrated on the motherboard) If you google HDA Codec you may get some info.
     
  9. munuainen

    Thread Starter New Member

    Jun 13, 2014
    11
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    It does, as I've tried to imply in the attached image. The gap between white connector outside edge and backside of the jack on the PCB is around 3.9mm.

    Correct. Technically one could borrow a +5V or +12V line from PSU but running an extension cord to front panel just gets really ugly.
     
  10. munuainen

    Thread Starter New Member

    Jun 13, 2014
    11
    1
    That's interesting. This does not, however, match the official HDA specs, nor does the dongle work as intended using mere AC97 connectors in the particular computer I'm repairing it for.
     
  11. munuainen

    Thread Starter New Member

    Jun 13, 2014
    11
    1
    Here's a heads up on the situation.

    I found a set of mini switches on eBay, that I deemed most likely suitable, based on their appearance. And lo and behold, they worked like charm!

    A copy of the eBay item image is attached in this message for future reference, in case eBay link goes dead. Title of the auction was '10 x SPST 4-Terminal Momentary Push Button Mini SMD SMT Tactile Switch'.

    Case closed. My thanks to all contributors.
     
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