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Soldering suggestions
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Soldering suggestions

by ufos8mycow on Thu Jul 02, 2020 12:03 pm

Hello everyone,

This is my first post here; and I'm really hopeful I can get some help.

I am working on integrating bluetooth into a new device, and one issue I have to overcome is the microphone. I'm starting with one of those "around the neck" bluetooth devices, since it gives me headset and phone capability built right in (exactly what I need) and it comes in a nice small package. Unfortunately, the built in microphone mounts directly to the board, and I need to use one placed elsewhere, since this board won't be near the user's mouth when it's in operation. Here is the board, with just the outer housing removed:

https://imgur.com/crV5vK7

And here it is with the connections de-soldered, and the button mic taken off. I haven't found a graceful way of doing it. A method other than snapping it would be welcome. I cleaned up the area as best I could, and there is some damage.

https://imgur.com/41LlTJP

My question is this. What would be the best way for me to solder new microphone connections into that round trace area left behind? This is a tinkered prototype, and further developments will be on a custom board; but for now, I'm getting proof of concept.

Any help would be very welcome, and thanks!

ufos8mycow
 
Posts: 4
Joined: Thu Jul 02, 2020 11:47 am

Re: Soldering suggestions

by adafruit_support_bill on Thu Jul 02, 2020 12:20 pm

You can solder wires directly to those solder pads. But you will want to add some strain-relief so they don't snap off at the solder joint. You can use tape, hot-glue or cable-ties. The object is to immobilize the wire end where it meets the solder joint.

adafruit_support_bill
 
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Re: Soldering suggestions

by ufos8mycow on Thu Jul 02, 2020 12:41 pm

I guess my question is, does anyone have a technique to solder this effectively without bridging the connections? Even my fine point tip looks like a tree trunk under the magnifier when compared to that pad. It's hard to get a glob in the middle that doesn't overlap.

Could I scratch the trace off one side of the circle?

ufos8mycow
 
Posts: 4
Joined: Thu Jul 02, 2020 11:47 am

Re: Soldering suggestions

by adafruit_support_bill on Thu Jul 02, 2020 12:57 pm

It should be possible with a fine-point conical tip like the Hakko "T18-I". I'd tin the wire and melt a small drop of solder onto the very end of it. Touch that to the center pad and heat with the iron just until it melts.

You could try cutting away part of the outer ring. for more clearance. A Dremel with a small cutting burr would probably be the easiest way to do that.

adafruit_support_bill
 
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Re: Soldering suggestions

by ufos8mycow on Thu Jul 02, 2020 2:24 pm

The dremmel suggestion was sort of what I was looking for. I had thought about scratching it away, but was concerned that I was doing something regrettable.

Thanks!

ufos8mycow
 
Posts: 4
Joined: Thu Jul 02, 2020 11:47 am

Re: Soldering suggestions

by adafruit_support_bill on Thu Jul 02, 2020 2:35 pm

From what we can see in the photo, it looks like the outer ring is connected to the ground-plane in 4 places. Just be sure no leave at least one of those connections intact.

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Joined: Sat Feb 07, 2009 10:11 am

Please be positive and constructive with your questions and comments.