Sankhya Node v4.1 — production files
====================================

Board:      60.000 x 80.447 mm, 2 layers, 1 oz outer copper, 1.6 mm FR-4
Assembly:   both sides
Derived from: Sankhya v4 (EasyEDA v6.5.54 export, 2026-05-19)

WHAT CHANGED FROM v4
--------------------
R6, R7 and R18 are shorted with copper on the bottom layer and removed
from the BOM and pick-and-place.

On v4 a net-labelling error (VIN_12V vs VIN_12VV) left these three parts
in series with the supply feeding U1, U2, U7 and U8:

    VIN_12V --[R6 10R]-- --[R18 10m]-- --[R7 10R]-- VIN_12VV

Two 0603 10 ohm resistors in the main power path is roughly 20 ohms in
series with a rail that has to carry amps. v4.1 removes them.

HOW THE BRIDGES ARE ROUTED
--------------------------
  R6   0.50 mm trace, straight across its own pads at y = 26.1620
  R7   0.80 mm trace, straight across its own pads at y = 26.1620
  R18  0.70 mm trace at y = 25.6000, from x 19.8034 to x 22.1856

R18 is NOT bridged across its own pads. A ground pour finger runs between
them; a straight bridge there would short the supply to ground. The link
instead joins the two existing vertical traces 2.1 mm above the part,
clear of the pour. R18's pads remain on their original nets as stubs.

Minimum clearance from new copper to any other net: 0.170 mm, at the
R6 bridge. That is above JLCPCB's 0.127 mm (5 mil) standard spacing for
1 oz, but it is the tightest point on the board - do not increase the
outer copper weight to 2 oz without re-checking it.

Solder paste apertures for all six pads were removed so the stencil does
not print paste where no part is placed. Solder mask openings were left
in place, so the bridges can be cut and real parts fitted if ever needed.

CONSEQUENCE YOU SHOULD KNOW ABOUT
---------------------------------
R18 was the 10 mohm shunt that U5 (INA219) measures across. With it
shorted, the INA219 will report approximately zero current and zero
power. Bus voltage measurement is unaffected. U5 is still populated.
Firmware that logs current from the INA219 should be updated to stop
publishing that channel, or it will log zeros.

CONTENTS
--------
  Gerbers.zip                   upload this to JLCPCB (PCB tab)
  BOM_V4-1_UTF8.csv             upload this (Bill of Materials tab)
  PickAndPlace_V4-1_UTF8.csv    upload this (Bill of Materials tab)

37 BOM lines, 61 placements.

Licence: CERN-OHL-P v2. OSHWA certification US002829.
sankhyafarms.com
