Current Consumption and Battery Life Estimation

A project log for Sensible Flow

Estimates water usage based on the tap handle rotation/movement and gives real time water consumption.

Josh JoyJosh Joy 03/20/2023 at 17:100 Comments

Using the CurrentWave / microCurrent Gold

When the Sensible Flow unit is connected to the Base unit via BLE, it consumes 600uA to sustain BLE connection in low power mode and also the IMU in low power. 

The IMU in low power mode is setup activity-based interrupt, the IMU sents an interrupt signal when motion is detected. An interrupt service routine runs which transmits the pitch, roll and yaw value of Sensible Flow. During transmission the device consumes 1.2mA. 

Only when the Tap is rotated it consumes 1.2mA for 2.5 seconds and goes back to sleep meaning 500uA.

Let's assume the tap rotations are 10 min per day 

                                                 = [ 1.2mA X 10 min + 0.6 mA X ( 23h 55m) ]  / day

                                                 = [ 12mA X 0.0167h + 0.6mA X 23.91h ] / day

                                                 = 14.54 mAh/day

Considering a battery size of 500mAh = 500 / 14.54  day

                                                                 = 34 days 9 hours