ESP32 combat robot controller (V2)

Hardware revision

In 1lb and 3lb combat robotics, every gram counts, so I prefer to build custom control boards to minimize weight. However, designing a new board for each robot became tedious, especially when most share the same fundamental requirements: receiving commands from a handheld controller and driving motors—both for movement and a high-current ESC/BLDC weapon system. To streamline future builds, I designed a compact, universal control board that integrates these core functions, making it adaptable to any new robot design. At its heart is a custom-programmed ESP32-C3-MINI, which communicates via BLE with an Xbox gamepad for seamless wireless control.

Features overview

After spending some time testing the new revision of my combat robot control board and refining the firmware, it’s finally performing as expected. This second revision of the combat robot control board was built with modularity, compactness, and power in mind—making it easy to integrate into a variety of designs while supporting high-current loads and reliable wireless control.

ESP32-C3-MINI

At the heart of the board is the ESP32-C3-MINI with a built-in PCB antenna for Bluetooth Low Energy communication with an Xbox controller. It offers plenty of GPIO for controlling onboard components, with additional pins available for UART and future expansions.

High-current DC input

Designed to accept up to 30V DC, the board features reverse polarity protection and large, easily solderable input pads. The power input is protected for continuous draws up to 30A—though trace limits are still being tested. With a 4-layer PCB and wide copper areas, it should hold up under combat conditions.

3.3V step-down converter

A robust AP63203 buck converter supplies a regulated 3.3V output at up to 2A. This powers the ESP32-C3 and also provides clean power to external peripherals and sensors.

Dual DRV8871 motor drivers

Two onboard DRV8871 drivers deliver up to 2A each to brushed DC motors—ideal for robot drive systems. They’re compact, thermally improved over the previous version, and simple to control via PWM.

External switch connector

For safety and convenience, a pair of solder pads allows you to add a remote-mounted power switch—acting as a master cutoff without obstructing access to the board.

High-current output pads

Parallel to the main power input, these pads allow direct connection to ESCs or other high-current devices, simplifying power distribution within the robot.

User I/O and debug tools

The board includes a basic debug LED, a tactile pushbutton for custom input, and two I/O headers with 3.3V and GND pins for expansion or prototyping.

The full project writeup is also published on Hackaday.io ↗.