The Smart Remote 3 product example is powered from two AA batteries.
Either alkaline (2 × 1.5 V) or rechargeable NiMH (2 × 1.2 V) batteries can be used. The battery circuit has a protection diode to avoid reverse current if the board is powered elsewhere. In parallel with the battery there is a connector (P3) that can be used for supply during development.
Figure 1. Battery schematic
Smart Remote 3 has a power switch that is connected to most of the circuits. The nRF chip controls the two transistors, which turn the power to the microphone and to the motion tracking device on or off. See the following figure. The low power accelerometer is always powered.
Figure 2. Power on/off switch schematic
