Power Management

• All the components of HomeR are powered by 2x 18650 Lithium-ion batteries (7.4V nominal).
• The battery feeds 2x DRV8874 carrier boards to drive 2x brushed DC motors.
• A Power Expansion Board (PEB) is responsible for converting the coarse battery power (could be 6V to 8.4V) to stabilized 5V, then providing it to the main computing device: Raspberry Pi 5 (RPi5).
• RPi5 powers up the micro-controller: Raspberry Pi Pico 2 and the LiDAR through the USB ports.
• Pico 2 eventually serves regulated 5V to power up the ultrasonic sensor and the motor encoders via the VBUS pin.
• The Pico 2 also powers up an Inertial Measurement Unit (IMU) module: GY-521 with 3.3V via 3V3(OUT) pin.

See diagram below to grab a intuitive idea of HomeR's power management.

Replay

• A relay board (HomeR Thalamus) is used for power and signal distribution but not illustrated in the diagram. The design is hosted in the homer_ee repository.