Combat Robotics - Team Artemis

This is the PCB I designed for our combat robotics team, competing in the UK Antweight category. The rules limit robots to a maximum weight of 150 g and require them to fit within a 100 mm × 100 mm footprint (approximately a 4-inch cube).

To meet these tight constraints, I aimed for a compact yet hand-solderable layout, selecting 0805-sized SMD components throughout. By using a six-layer stackup, I dedicated inner layers to solid power and ground planes, which minimized the board's overall size while improving current handling and reducing noise.

The Design

The core processor is the ESP32-MINI-1 module, chosen for its small footprint, strong performance, and integrated Wi-Fi capabilities. It drives a pair of DRV8231DDAR H-bridge motor drivers (from Texas Instruments), which control the brushed DC motors. Current-sense amplifiers connected to the H-bridges provide feedback to the ESP32, enabling basic monitoring of motor load and performance.

Power for the ESP32 comes from one of two sources: a USB-C connector (primarily for programming and debugging) or a LiPo battery (the typical runtime supply). In both cases, the input voltage is either 5 V (from USB) or a nominal 3.7 V (from the LiPo). Since the ESP32-MINI-1 requires a supply voltage in the 3.0 V to 3.6 V range, the design includes an LDO regulator that steps down the input to a stable 3.3 V for the module and other logic-level components.

For safety, the board incorporates over-current protection for the LiPo battery. Over-charge and over-discharge safeguards are unnecessary here, as charging occurs externally and is not handled on-board.

The PCB