Handoff - schematic, board layout and fab files
===============================================

One wristband's board. A handshake needs two, so build two.

Project write-up and full sources: https://github.com/rahuljeyaraj/Handoff

What is in here
---------------

schematic/
  handoff-schematic.pdf     the schematic, plotted from the KiCad source
  handoff-schematic.png     the same sheet as an image

layout/
  handoff-board-layout.png  both copper faces side by side
  pcb-top.png               top face
  pcb-bottom.png            bottom face, mirrored so the text reads

fab/
  handoff-pcbway.zip        ready to upload to PCBWay, unopened
  gerbers/                  the same Gerbers and drills, unpacked to read
  order.md                  every answer the PCBWay order form asks for,
                            and what to check on their preview before paying
  drills.md                 the drill table

bom/
  bom.csv                   the bill of materials

kicad/
  the KiCad 8 project, with the custom footprints and symbols this board
  needs. Open handoff.kicad_pro.

The board
---------

40 x 62 mm, 2 layers, 1.6 mm, 1 oz copper. HASL is fine. ENIG is the one
upgrade worth paying for, for flat pads under the amplifier's 0.65 mm pins.
The smallest run is five, which is the right number anyway: two bands and
three spares.

One value to know before you solder
-----------------------------------

The board and bom.csv were laid out with R1, R2 and R3 all at 1 MOhm. What is
fitted, and what every measurement in the write-up was taken with, is
R1 = R2 = 100 kOhm and R3 = 1 MOhm. The silkscreen does not know that.

C6 is a spare footprint and is left empty.
