Build Instructions

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• 1

  PCB

  This device has a 4-layer PCB, which is 6x4cm in size. I've ordered 5 pieces on Allpcb, which costed 33 USD and 21 USD for shipping to Germany. The price is okay for prototyping, since home-made is no more an option and local PCB manufacturer require 200 Euro for that thing. Actually I have other PCBs to order the same time, so the shipping cost is also acceptable.

  For 50 pieces of PCB, the average cost per PCB is only 1.3USD at Allpcb, so it's really a matter of prototype or production.

• 2

  BOM

  There are approximately 40 different components and 90 parts on the PCB. The types of the components will be reduced if new version is to design. I've got most of them already in my boxes at home, after long time collection for different projects. However most of them could be ordered at Mouser, 90 percent, which still sells to private customers in Germany. The BOM cost is for the current version still high, if only 1 piece is to build. For 1 piece they cost about 14 Euro for 93% of the BOM at Mouser.

  The BOM list can be found in the uploaded files.

• 3

  PCBA

  Soldering of SMD components at home requires patience. If one is skilled on soldering, then the only difficulty on this board is the transistor, which is quite small and has a thermal pad underneath. I would like to replace this component with a SOT package for new version.

  A magnifier is quite helpful. Most resistors and capacitors have 0603 package, which are still ok for hand soldering under magnifier.

  The current version has two-side placement due to size limit. However it would be possible to place all components on top side for the new version, leaving only some through hole components.

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