Hw Mayfly 0.5b ECO R04

Summary: Measure Vbat accurately with R divider on AA0. Cost is about 3uA through R+R divider. (this was R02 need to update board) One 1M/battery and 100K/Ground Resistors Leaded Through Hole ,1/8W eg RNF18FTD1M00 1% 100ppm & RNF18FTD100K 1% 100ppm One 10nF (to 100nF) C sampling capacitor from GND to AA0. 10nF Cer Kemet C410C103K5R5TA7200 or Vishay K103K10X7RF5UH5
One Short 2.5" wire wrap wire, stripped both ends approx 1/8" and 1/4"
Shrink wrap as needed, for protection (?1/8" & 1/4" )

Applies to Mayfly 0.5b. Mayfly 1.x has a more accurate power Vref.
With no power, and no wires attached to the Mayfly 0.5B
a. Wind the resistors as shown, 100K&10n to 1M. and solder wire 1/4" stripped to common R
b. Solder to [1] - GND 100K&10nF
c. Solder to [2] - Vbat 1M
d. Solder to [3] - wire wrap to AA0 and cut off excess