# Waveshare Cobra Flex > All-metal modular drive-by-wire 4WD robot chassis with ESP32-S3 controller, hub motors with built-in FOC control, CNC metal suspension, LIN bus communication, IP32 protection, and 12 kg payload capacity for heavy-duty robotics. ## Quick Facts - **Brand:** Waveshare - **Board Type:** robot-platform - **Price:** ~$319.99 - **Product Readiness:** consumer - **CPU:** ESP32-S3 - **CPU Architecture:** Xtensa LX7 dual-core - **CPU Cores:** 2 - **RAM:** 512KB SRAM - **Flash:** 8MB - **USB:** USB Type-A - **Power:** 9-12.6V DC / 3S2P 18650 Li-ion - **Operating Voltage:** 3.3V - **Dimensions:** 235.25 x 173 x 101.24mm - **Weight:** 2375g ## Connectivity - **Wifi:** 802.11 b/g/n - **Bluetooth:** BLE 5.0 ## Open Source - **Firmware:** Yes - **Schematics:** No - **PCB Layout:** No ## Compatible Firmware arduino, esp-idf ## Use Cases - mobile-robot - autonomous-navigation - heavy-payload-robot - industrial-robot ## Components - **ESP32-S3** (mcu): Dual-core WiFi & BLE 5.0 controller with strong/weak electric isolation — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.espressif.com%2Fsites%2Fdefault%2Ffiles%2Fdocumentation%2Fesp32-s3_datasheet_en.pdf&ref=openhardware.directory&product=waveshare-cobra-flex&source=md-export) - **FOC Hub Motor** (motor): Hub motor with integrated FOC control circuit, 180 RPM no-load at 12V, 0.15 Nm/V torque (x4) — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.waveshare.com%2Fwiki%2FCobra_Flex&ref=openhardware.directory&product=waveshare-cobra-flex&source=md-export) ## Protocols - **LIN** - **UART** - **USB** - **HTTP** - **RS-485** - **TTL** ## Accessories - Raspberry Pi - Raspberry Pi 4B ## Available Software - **[Cobra Flex Firmware](https://openhardware.directory/r?to=https%3A%2F%2Fwww.waveshare.com%2Fwiki%2FCobra_Flex&ref=openhardware.directory&product=waveshare-cobra-flex&source=md-export)**: Open-source ESP32-S3 firmware for chassis control ## Description # Waveshare Cobra Flex The Waveshare Cobra Flex is a heavy-duty, all-metal modular drive-by-wire robot chassis designed for demanding robotics applications. It features four hub motors with integrated FOC (Field-Oriented Control) circuits, independent CNC-machined metal suspension on each wheel, and an ESP32-S3-based controller board with strong/weak electric isolation. ## Chassis & Suspension The compact chassis (235.25 x 173 x 101.24mm) weighs 2,375g and is built entirely from metal. Each of the four wheels has its own independent CNC metal suspension system, enabling superior shock absorption and terrain adaptation. The chassis handles 30-degree inclines and supports a vertical load capacity of 12 kg, making it suitable for carrying heavy payloads like robotic arms, LIDAR stacks, or computing platforms. ## Hub Motors with FOC Control Unlike the N20 geared motors used in the WAVE ROVER and RaspRover, the Cobra Flex uses hub motors with built-in FOC control circuits. Each motor communicates with the main controller via a LIN bus protocol. At 12V, they achieve 180 RPM no-load speed and 100 RPM rated speed with 0.15 Nm/V rated torque. The 74.5mm diameter wheels on a 154mm wheelbase provide a top speed of 0.53 m/s with zero-radius turning. ## Controller & Communication The ESP32-S3-based driver board provides WiFi (AP/STA mode for short-range debugging) and Bluetooth connectivity. Host computer communication uses USB, UART, or HTTP protocols. The chassis supports RSBL and ST/SC series bus servos via TTL and RS485 interfaces, enabling modular attachment of robotic arms and pan-tilt systems. ## Power System The chassis accepts 9-12.6V input and is designed for 3S2P 18650 lithium battery configurations (recommended 5000 mAh x 6 cells, not included). The large internal cavity accommodates batteries and computing modules. A DC 5.5x2.1mm charging port accepts the included 12.6V 2A power supply. Battery life is approximately 10 hours. ## Expansion Two 1020 aluminum profile rails (110mm pitch) provide a standardized mounting system for host computers (Raspberry Pi, Jetson Orin Nano), LIDAR, cameras, and custom payloads. The IP32 protection rating offers basic dust and drip resistance for indoor and light outdoor use. ## Software All firmware source code is open-source and available for secondary development. The ESP32-S3 supports Arduino IDE and ESP-IDF development environments. ## Where to Buy - [Waveshare](https://openhardware.directory/r?to=https%3A%2F%2Fwww.waveshare.com%2Fcobra-flex.htm&ref=openhardware.directory&product=waveshare-cobra-flex&source=md-export) — $319.99 ## Resources - [product](https://openhardware.directory/r?to=https%3A%2F%2Fwww.waveshare.com%2Fcobra-flex.htm&ref=openhardware.directory&product=waveshare-cobra-flex&source=md-export) - [wiki](https://openhardware.directory/r?to=https%3A%2F%2Fwww.waveshare.com%2Fwiki%2FCobra_Flex&ref=openhardware.directory&product=waveshare-cobra-flex&source=md-export) ## Tags `robotics`, `rover`, `esp32-s3`, `4wd`, `foc`, `hub-motor`, `open-source`, `heavy-duty`, `modular`, `drive-by-wire` ## Images ![Waveshare Cobra Flex](https://nbg1.your-objectstorage.com/openhardware-directory/entities/waveshare-cobra-flex/0c7cba7439c4.jpg) ![Waveshare Cobra Flex](https://nbg1.your-objectstorage.com/openhardware-directory/entities/waveshare-cobra-flex/770cbe682ff7.jpg) ![Waveshare Cobra Flex](https://nbg1.your-objectstorage.com/openhardware-directory/entities/waveshare-cobra-flex/bca76450014c.jpg) --- [View full device page](https://openhardware.directory/devices/waveshare-cobra-flex)