Revisions & Schematic

Revision R3

This revision had been tweaked for lower power overall. In addition it allows for Panasonic ultra low power PIR sensors to be installed instead of the default chinese HC-SR501 sensors. These Panasonic sensors are much smaller and available in idle consumption as low as 1uA, although they come at a steep price. It also features an optional BME280 temperature/humidity/atm-pressure sensor. The power switch has changed to a much more robust part. There are some solder jumper pad changes and new jumpers that allow more flexibility. The charging rate was changed to a default of 212mA (4.7K resistor). Pullups (4.7K) were added to SCL/SDA pins. An antenna through hole was added so it’s easy to route it straight to the back cover slot. A charge enable solder jumper was added – this is useful when powering from 3XAA/AAA batteries – cut it open to disable charging, resolder to re-enable it.
DSC_9817

Revision R2

Revision2 changed to PCB ENIG gold finish and fixes some bugs, most notably the FTDI chip addition of 27ohms inline on the D+/D- traces for better signal integrity. Below are some shots and details of these changes.