Tue, 20 Nov 2012
For the first time in my life, i have tried to solder SMD components (as I have written before, I am working on DYI LED lights for my bike). The component side looks OK, and soldering through-hole components went without problems. The SMD parts were a bit tricky, though.
I have used an ordinary soldering station with temperature regulation, but the results are not pretty. I wonder what is required to achieve this level of quality (watch from 14:10). One possible problem might be that some components on my board (especially the smallest sensing resistors) are connected to the highest-current and thus thickest paths, which suck great amounts of thermal energy when soldering.
Anyway, from the preliminary testing, it seems that my board works. So far I have found the following problems:
- The programming connector is bigger than I expected. I have solved this by using the angled variant instead, and adjusting it using knife :-)
- The silk layer labels marking the polarity of components (electrolytic capacitors, diodes, etc.) can be placed under the components, except for the labels of connectors, which are needed even after the components are soldered!
- I should have added low-pass filters to the A/D converter inputs, at least for the feedback of the PWM-regulated converters. I think I would be able to overcome this in the firmware, though.
- Next time, I would probably design the board with round corners :-)
Now it's time to finish the firmware and to start adjusting the mechanical parts. I have already made the front spotlight and rear spotlight, and I want to make a LED string. Any tips about making a waterproof LED string out of 3mm through-hole LEDs will be appreciated. Should I use silicon, shrink-wrap tube, or what?