Hexapod PCB 2

MADHEX-v2

the Fully open source 6 legged hexapod robot

• Custom controller PCB
• Fully open-source
• great mechanics design with amortization

the 18DOF hexapod robot

the README include

• Overwiew
• Features
• Electronics
• CAD
• firmware
• BOM

Overview

MadHex v2 is an open-source hexapod robot designed for people who wanna build their spider friend and learn building — CAD, PCB , and design are all custom-made. This repository contains everything needed to reproduce the robot: CAD source and manufacturing files, PCB design and production files, bill of materials

Currently the project is in procces of building

Features

• Fully custom mechanical design , all parts are 3d printable
• custom control PCB : schematics , 4 layer of layout , kicad project , and manufactoring files
• 2 Full BOM files for both PCB and Robot
• great design with beatiful decisions

Electronics PCB

The schematics

the renders

Custom 4-layer control board

Key Features :

• MCU: ESP32-S3-WROOM-1 — great wifi/bluetooth MCU
• IMU: BNO055 — 9-DOF orientation for balancing
• Power input: XT60 connector - for battery connection
• Power protection: low-side N-MOSFET reverse-polarity protection NTMFS5C404NL + SMBJ10CA TVS diode + 30A fuse
• Regulation: two TPS563201 buck converters: battery → 5.3V → Schottky → 5V rail → 3.3V
• USB power path: Schottky diodes keep USB and the battery side separated
• Power monitoring: INA226 current/voltage sensor (I2C) with a 2m shunt + analog voltage divider as backup
• USB-C: USB with USBLC6-2P6 ESD protection
• Status LED: WS2812 RGB
• Servo interface: 2× independent half-duplex UART buses , 3 legs per bus — driving serial bus servos over a single data line per bus instead of PWM channels
• Connectors: 6 3-pin leg connectors (J2–J7), one per leg makes the wiring a lot easier

Files:

• Schematic: download the schematics
• Gerbers + drill files : Download the manufactoring files
• BOM: download the PCB BOM

Board spec:

CAD

Fully custom mechanical design, designed in autodesk Fusion every part is 3D-printable

values:

Segment lengths were chosen using the servo torque

3D printing:

PETG was chosen over PLA for better impact resistance sustained servo load — legs take repeated ground-impact stress during walking.

Foot amortization (printed spring):

Each foot includes a printed compliant spring element (PETG) acting as a passive shock absorber — it absorbs ground-impact impulse on footfall instead of transmitting it directly into the leg linkage/servo horn, reducing mechanical stress and jitter during walking.

Files:

Full parts list, printed vs. purchased components, and quantities: see the main BOM

Bill of Materials

Two separate BOMs are provided — one for the full robot, one for the PCB only.

Full Robot BOM

Full file: see the full main BOM

PCB BOM

Full file: see the full PCB BOM

Firmware

Written in C++ with PlatformIO (Arduino framework) for the ESP32-S3

Features:

• Inverse kinematics from the CAD joint points, with joint limits
• Gaits: ripple (default), tripod and wave
• Movement: forward, backward, sideways, turning in place, combined; adjustable body height
• States: sit, stand up, stand, walk, sit down, emergency stop
• Safe startup: servo output is off after power-up; when enabled, it reads every servo position and moves slowly to the sitting pose
• Calibration: trim and direction for each of the 18 servos
• Safety: low battery, servo overheating, emergency stop, stop on lost Wi-Fi link
• Sensors: INA226 current and voltage, BNO055 orientation, optional body leveling
• Status LED: a color for each robot state
• Tests: 200+ unit tests that run on a PC without hardware

Pinout:

Build and flash (VS Code + PlatformIO):

cd Firmware
pio test -e native        # unit tests on the PC
pio run -t upload         # flash the ESP32-S3 over USB-C
pio run -t uploadfs       # upload the web control page

a bit about the project history : i always wanted to make the hexapod but had no skills so 1 year passed i got pretty good skills in cad electronics and etc so now this project is real