Sensor board w/ MAX8903 battery charger and NRF24l01+ radio socket

Charger IC has a complete constant current, constant voltage algorithm. It is a low quiescent current, 3.7V Lithium battery charger. The maximum charge current is set at 250mA.

Low battery drain when charged 0.05µA

On the back there is an environmental sensor BME280. It can measure temperature, humidity and barometric pressure. Adafruit has a nice code example for this sensor. Tested working.

Other features on the board: NRF24l01+ radio socket NRF24 socket with CE and CSN pins connected to digital pins 7 and 8 ( you use RF24 radio(7, 8); in Arduino code). There is a 4.7uF capacitor connected across Vin and GND of the port NRF24

High efficiency buck-boost regulator The board comes with a TPS63001, 3.3V DC-DC buck-boost converter. It has low power consumption of 30μA, typically, while delivering at least 800mA in boost mode and has a 96% efficiency.

3amp 30V n-channel MOSFET for regulating external components such as solenoids. The gate is connected to digital output D5.

Low power (2mA) LED diodes.

There are few such boards available and none with this kind of versatility. Fully Arduino compatible with Arduino LilyPad 3.3V @ 8MHz bootlader.

Schematic can be found here