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12 – soldering 1.6x1.6mm (SOT-563) sensors to leads

A project log for micropower micrologger [mPmL]

A set-and-forget I2C/digital datalogger. Size: 25.3x 18x 10mm incl. battery. Runtime: > 1year

JanJan 10/08/2018 at 18:234 Comments

TL;DR it is possible by hand

HOW TO

Here is my first try soldering 0.15mm (0,0059") wire to a TMP112 sensor. These come in an SOT-563 package with 0.5mm pitch.

Copyright: Würth Electronik (Source: http://katalog.we-online.de/de/pbs/WE-TVS-HS#vs_t1:2_ct:1)

I made a cutout in a piece of cardboard, glued it to a piece of aluminum (we know it's aluminium, right?) and tried soldering wires to it. Worked OK, though I had to use a really fine tip for that. Took me around 10 minutes.

sketchy setup but it worked

The main problem is, the wire lengthens a bit while soldering, so it easily slides off the pad. Should I need to solder a few of them I need to add a weight or spring to one side which compensates for that.

directly after soldering

After cleaning a bit, this is what I ended up with:

Of course opposite pins are still connected to each other, but that will be corrected when doing my next tests with a better setup. I think I know how this will work much better...

BTW: Cutting the leads in between with a side-cutter didn't work well (topmost contacts), using a cutter knife does a good job though:

Discussions

Morning.Star wrote 10/12/2018 at 11:40 point

Heh, nice technique cutting away the surplus wires. :-) Good one.

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Jan wrote 10/12/2018 at 13:57 point

Thanks! Going to build a jig so I do not have to cut them

like this. It's kind of much force on the sensor to use a razor blade for that...

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Morning.Star wrote 10/13/2018 at 08:11 point

I work with a No.11 scalpel for everything, it has a needle tip and doesnt tin so you can hold wires down and solder them.

I also use the round ones sometimes. These can be turned into a saw by scraping sideways just once across a bit of oxide sandpaper... You dont want to blunt it, just take nicks out of it...

You can also glue the wires temporarily to the device with  a blob of nail varnish or superglue, cut through that and then wash the cutouts and glue away with acetone. ;-)

Jigs are great, but as painful to make as soldering the device IMO. I like your technique, if I can get away with a procedure over hardware I will lol, its kind of like programming.

Good luck! :-)

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zakqwy wrote 10/11/2018 at 16:44 point

nice!!

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