+[[!tag tags/rockets]]
+After a long hiatus for various reasons, I finally had the chance to try my
+hand at hand loading a [TeleMetrum](http://altusmetrum.org/TeleMetrum)
+board today!
+
+Sadly, I wasn't able to completely load any boards, because I somehow ended
+up with the wrong [Digi-Key](http://digikey.com/) part numbers for 4
+capacitors, one of which is a critical value. I placed an order for the
+missing parts and a few other bits we'll need eventually, hopefully they'll
+be here in a couple days and I can try to load a board with all the parts.
+
+Instead, what I did today was a a partial load of a board with the goal of
+testing the various power supplies. Seemed like a good idea, since I've
+had my share of odd problems with power supplies in the past. This also
+gave me a chance to try out my solder paste stencil, get some experience
+hand-placing the tiny 0402 passive parts, and an excuse to see if I could
+hit the solder reflow temperature profile adequately with my electric
+cooking skillet and IR non-contact thermometer.
+
+The good news is that it all worked right the first time! We're successfully
+charging a LiPo battery from USB power, and successfully making 3.3 volts for
+the electronics from that. The resistor divider designed to allow the LiPo
+battery voltage to be sampled by the CPU's analog to digital converter is
+also working fine.
+
+A few observations are in order, however.
+
+Getting the right amount of solder paste down on the board requires some
+finesse with the spreading blade and the stencil. I think the paste was a
+bit heavy around the CC1111 footprint, as I ended up with some bridged
+pads. Since I didn't load the actual CPU part, it could just be that not
+having something real there to wick up some solder meant there was enough
+to form the bridges. Don't know. The amount of solder on the ground pad
+in the middle of the chip looks good, though!
+
+The 0603 sized LED in the power supply circuit was the only part that didn't
+self-align correctly. I may have had it a bit too far to one side. The pads
+on the part have notches in the end, and it looks like one side of each is
+more or less centered, so I think surface tension did the best it could with
+what I gave it to work with. The LED soldered ok, isn't shorting to anything
+else, and clearly works fine... but I'd be happier if it were aligned better.
+
+Found and fixed a solder bridge between two pins on the surface-mount USB
+connector before first application of power. Could be further data that the
+paste layer was a bit too thick. On the other hand, I had to wiggle the
+connector around a bit to get it aligned correctly, so I may have smudged
+the paste into a bridge while doing that.
+
+I also note that there's some visible flux left on the surface of the solder,
+particularly on big paste areas like the feet of the USB connector. I
+suspect this means I didn't dwell long enough at either or both of the preheat
+or ultimate reflow temperatures. Since all the parts clearly soldered
+adequately to function, I'm still pretty happy... but since the rockets we
+fly experience violent accelerations during boost, this is something I'll
+play with on future reflows.
+
+All in all, a great way to spend an afternoon, and a big step forward for
+the TeleMetrum project!
+
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