This repository implements the firmware for the hoveboard sideboards. The hoveboard comes with two identical sideboards that can be flashed with this firmware.

• Hardware
• Example Variants
• Flashing
• Wiring iBUS Receiver
• 3D Visualization Demo
• Contributions

The original sideboard hardware supports one 4-pin cable that originally was connected to the hoveboard mainboard. It breaks out GND, 12/15V and USART. Additionally, two ports are used to connect to the LED boards. On the back of the board, two Photo Interrupter Optical Switches can be found, originally used to detect if a human is standing on the hoverboard.

The LED boards consist of colored LEDs (blue, red, green, orange) used for design and to inform the user about the current hoverboard state. Below the pinout of the LED boards is shown.

The sideboard brain is an STM32F103C8T6 with the pinout shown in the follwing figure:

A very important component of the sideboard is the IMU MPU-6050 from Invensense. The MPU-6050 determines the board orientation by combining a 3-axis gyroscope and a 3-axis accelerometer on the same silicon die, together with an onboard Digital Motion Processor™ (DMP™), which processes complex 6-axis MotionFusion algorithms. The DMP™ offers many features, such as:

• Accelerometer and Gyroscope raw data output
• Quaternion output
• Temperature output
• Pedometer
• Interrupts on gesture events such as Tap on all axes or Orientation change
• Low-power modes
• Self-test and calibration

The MPU-6050 pinout and orientation of axes is shown in the follwing figure:

For more details see the MPU-6050 datasheet and MPU-6050 registers.

This firmware offers currently these variants (selectable in platformio.ini or config.h):

• VARIANT_DEBUG: In this variant the user can interact with sideboard by sending commands via a Serial Monitor to observe and check the capabilities of the sideboard
• VARIANT_HOVERCAR: This variant can be used for Hovercar build. An RC receiver with iBUS protocol can be connected to the AUX serial Rx pin (see schematic)
• VARIANT_HOVERBOARD: In this variant the sideboard is communicating with the mainboard of a hoverboard using the FOC firmware repository

Of course the firmware can be further customized for other needs or projects.

On the sideboard, there is a debugging header with GND, 3V3, SWDIO and SWCLK. Connect GND, SWDIO and SWCLK to your ST-Link V2 programmer. The 3V3 can be either obtained by connecting the pin to the ST-Link programmer or powering the sideboard with 12/15V.

If you have never flashed your sideboard before, the MCU is probably locked. To unlock the flash, check-out the wiki page How to Unlock MCU flash.

To build and flash choose one of the following methods:

• Fork the project
• Modify desired source files and commit
• Go to Actions (in the repo top menu)
• Click on latest build
• Download the build zip file from the Artifacts section
• Upload desired firmware.bin file using ST-Link Utility

• open the folder in the IDE of choice (vscode or Atom)
• press the 'PlatformIO:Build' or the 'PlatformIO:Upload' button (bottom left in vscode).

• in Keil uVision, open the sideboard-hack.uvproj
• if you are asked to install missing packages, click Yes
• click Build Target (or press F7) to build the firmware
• click Load Code (or press F8) to flash the firmware.

• prerequisites: install ST-Flash utility.
• open a terminal in the repo check-out folder and if you have definded the variant in config.h type:

make

or you can set the variant like this

make -e VARIANT=VARIANT_####

• flash the firmware by typing:

make flash

An RC transmitter (Flysky FS-i6S or FS-i6X) can be connected to the sideboard using an FS-iA6B receiver as shown in the following schematic:

By converting Quaternions to Euler angles, we can make a 3D visualization example in Processing as shown below. For this Demo VARIANT_DEBUG was used.

Every contribution to this repository is highly appreciated! Feel free to create pull requests to improve this firmware as ultimately you are going to help everyone.

If you want to donate to keep this firmware updated, please use the link below: