WeatherShield is now at R2 and although the PCB is very similar to R1 there are some significant differences. The R1 used to have a BMP180 until Bosch decided to stop making it. So R2 came about partly because of that reason, and is now shipped with a BME280 which includes all Temperature/Humidity/Pressure readings all in 1 sensor. This sensor is pretty popular it seems so hopefully the supply will be plenty for a long time.

Here’s a look at R2:

Notice a few changes:

• The voltage monitor circuit is now without a mosfet – this was removed and a resistor was added (the angled resistor) to tie the circuit permanently to A7.
• The old pads are still there so including the mosfet as on R1 is an option if someone really wants it.
• there is now a solder jumper to allow disconnecting the battery monitor from A7
• The Si7021 pads are still there if you’d like to add that sensor yourself

The board will idle at around 3.5uA when the sensor is put to sleep because of the voltage monitor. That’s still very low power but if you want 100nA instead and don’t care for battery monitoring, cut the jumper to A7.