LED Display and ButtonThe controller was powered by 4 Alkaline 1.5V AA batteries. Four buttons are idle high with 110k pull-up resistors and powered by 5V from linear voltage regulator. LEDs display which indicated the status of communication were powered directly from batteries and controlled by TIVA PB6.
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Controller Battery Life Calculation
Our team uses four 1.5V rechargeable Li-ion AA batteries to power our controller (PAC) with each battery have a power of 4200 mAh. The maximum power dissipation occurs when all of the switches are closed and all of the LEDs are on. Additionally, worst case power consumption is assumed for Tiva, Xbee and accelerometer. To have an 8-hour battery life, the current consumption by PAC should be limited by following value:
Maximum Current (mA) = 4200 mAh / 8 hours = 525 mA
Our controller is capable of running for 8 hours. The following table is a summary for all the power consumption in our controller: