Tried really hard to hit my milestone for today (electronics assembled), but it's just not happening. I have this RoHS compliant lead-free silver solder, and it's absolutely a pain to work with. Part of it is that I'm used to rosin-core solders, but even using flux the higher melting point is just killing me, particularly with the weak-ass soldering iron I have.
It doesn't help that the solder tip is huge and the solder itself is larger in diameter than the SOIC pins I'm soldering. For those, I finally settled on cutting off little chunks of solder and pushing them onto the pin/pad and squishing it there until the heat finally melts it and it flows onto the pad (which is fortunately pre-tinned).
What finally made me give up was the difficulty soldering the through-hole pins. Something that should have taken 5 seconds per pin now takes 30, and that's really frustrating. Also I screwed up the PCB rework because I was pushing too hard on the trace when soldering to it, so now the SPI SS line is going to look very different. There may be an alligator clip involved.
I think I am just going to have to get a second rev of this helicopter interface board. There was the printout scaling fiasco (a.k.a. why the hell doesn't SparkFun have a dimensioned layout for that 9dof IMU board), and this rework, and along those lines it'd be good to have a connection to the AHRS Rx/Tx pins. Finally, some weight reduction (thinner board and/or hatching of the ground plane), a solder mask, and top side ground connections would also be nice to have. And we'll see how the mechanical design goes; there may be some adjustment to hole placement.
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