Friday, June 7, 2013

Problems and Distractions

I haven't been able to post in quite a while - far too many things in real life distracting me.  But now that I have gotten back to hobby time, I am expanding my system with an I2C interfaced GPIO extender.  Everything worked great on the workbench, but refused to work at all once installed.  It appeared that the bi-directional buffer chip that I used to connect the Pi to I2C wasn't working, which made no sense.

I broke down and pulled the interface board down and brought it to the workbench.  Under the magnifier, the problem was immediately obvious.

Soldering is an art.  It takes practice, and I was terribly out of practice when I started this blog (and made this board.)  Bottom line, the SDA and SCL lines were shorted by some over-zealous soldering.  Since I hadn't used I2C, it was never a problem.

I have a feeling I am going to replace this board with a completely re-designed version before too long.


  1. Ted,
    New solder would go a long way to preventing this. The flux core only has about a 3-year shelf life. May I suggest Kester - No-Clean 245 Solder Wire, .031" dia., Core Size-66 Sn63Pb37. This size and formulation of solder works great for me. And I thought it was my soldering skills that were deteriorating...

    1. I remember you mentioning that last time we met. I will get some new solder before I do any more building.

      Still working on the sprinkler interface. Hope to have a post up on that soon.

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