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What I'm looking for is to be able to solder a mechanical pressure plate/arm to a PCB, where a plastic tab can be inserted.

This contact (when connected) will complete the 3.3V/5V supply and turn on the device. Similar to how some manufacturers put the little plastic tabs in the battery housing so that all you have to do to start using the device is to pull the tab out.

mechanical pressure plate

In the picture above, the red rectangle would be the PCB viewed side-on. The blue component would be the little conductive arm/plate which naturally wants to close and make contact with the other little blue area. The orange line would be the plastic tab preventing it from making contact until removed.

Any ideas if such a thing exists and what it would be called?

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    \$\begingroup\$ Can you can use a regular micro-switch and some clever enclosure thoughts? \$\endgroup\$ – Jeroen3 May 9 '19 at 11:11
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    \$\begingroup\$ It's a non-corrosive contact like Au or SS \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 May 9 '19 at 11:21
  • \$\begingroup\$ Would this be used for mass production or can a solution involve manual soldering? \$\endgroup\$ – pipe May 9 '19 at 13:51
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    \$\begingroup\$ Also, this probably breaks the "product recommendation" policy, but I'm not going to VTC because I would like to see this type of "does it even exist, or how do I solve it?" questions allowed. \$\endgroup\$ – pipe May 9 '19 at 13:52
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Technically this is a rebut to Scott Seidman's answer, but not practically.

  1. You could have your contact stamped out of bimetallic material, so that it curled away from the board when hot. On reflow the solder should (or maybe not) solidify before the contact has finished curling into the board. So, either a nice preload, or a device that reliably rips itself out of the partially-cooled solder every time.
  2. You could make the contact with an inverted "U". Solder it on with no preload, then crimp the "U" tighter after soldering. Presto -- instant preload. With more elaborate crimping tools, you could use a mostly flat strap.
  3. You could contemplate the cost in engineering hours and grief of either of the above two options, and consider that a cheap surface-mount slide switch is 30 cents in quantity. Estimate the engineering cost, divide by the anticipated quantity, and compare that to 30 cents...
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  • \$\begingroup\$ I wouldn't quite say "rebut" so much as "expand" Those are clever methods to create the preload, but not so clever that they're available off the shelf! I'd put them in the "jury-rig" category I mentioned.. \$\endgroup\$ – Scott Seidman May 9 '19 at 17:02
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    \$\begingroup\$ @ScottSeidman I could see doing it on a device that was going to be produced in 10,000 / lot or more quantities (or maybe 100,000). But you'd need a pretty high manufacturing quantity to amortize the engineering needed so that it's no longer jury rigged. \$\endgroup\$ – TimWescott May 9 '19 at 17:14
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I suggest that what you're looking for doesn't exist, because there would be no way to preload the spring contact during reflow so as to make reliable contact.

That leaves you trying to jury-rig something. A quick, but expensive solution would be to use a coin cell holder, with a metal blank substituting for the battery. I'm sure you could do better by putting more thought into it.

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