• 27 May 2024: Fix a bug in the calculation of the synthetic GPRMC timestamp, which could cause timestamp rollback. Additionally, we add checksum verification for GPRMC.
• 20 May 2024: According to Livox Avia's pin requirements, we convert PPS TTL level to RS485 level and supplement it with more detailed electronic connection and material list.

This repository provides the CAD files (with suffix “*.SLDPRT and *.SLDASM”) for our handheld device, which can be opened and edited with Solidworks. All of the modules are suitable for printing with FDM (Fused Deposition Modeling). In addition, we have also open-sourced our hardware synchronization scheme, as well as the STM32 source code and hardware wiring configuration instructions.

Contributors: Sheng Hong and Chunran Zheng

├── handhold_cad/ - CAD source files
│   ├── ...
├── livox_ros_driver/ - Livox LiDAR ROS driver
│   ├── ...
├── livox_sdk/ - Livox LiDAR SDK
│   ├── ...
├── mvs_ros_pkg/ - Camera driver
│   ├── ...
└── stm32_timersync-open/ - Embedded engineering folder
│   ├── USER/ - Main functionality folder
│   ├── ...
└── README.md - Project homepage document
└── ...

The assembly instructions are demonstrated in the GIFs below. Each module is clearly labeled corresponding to the name of its STL file.

The guide for the electronic connections is presented as follows:

Livox AVIA LiDAR M12	Peripheral Function	Diagram
PIN 1	Power: +	AVIA 12-Pin Interface, top: female bottom: male
PIN 2	Power: -
PIN 7	Ethernet: right PIN3
PIN 6	Ethernet: left PIN3
PIN 5	Ethernet: green PIN2
PIN 4	Ethernet: green / white
PIN 11	RS485_B
PIN 12	RS485_A

Note: STM32 PB5 (PPS signal) is converted from TTL to RS-485, resulting in RS-485_A and RS-485_B. STM32 TXD (GPRMC) is converted from TTL to USB and sent to the PC. If you are using the Mid360, you can directly connect STM32 PB5 to PIN 12 of the LiDAR M12.

MVS Camera 6PIN	Name	I/O Type	Description	Peripheral Function	Diagram
PIN 1	DC_PWR	--	Power Supply		MVS Camera 6-Pin Interface
PIN 2	OPTO_IN	Line 0+	Optical Isolation Input	STM32 PA1
PIN 3	GPIO	Line 2+	General Purpose Input/Output
PIN 4	OPTO_OUT	Line 1+	Optical Isolation Output
PIN 5	OPTO_GND	Line 0- / 1-	Optical Isolation Ground	STM32 GND
PIN 6	GND	Line 2-	Ground

Item	Pics	Purchasing list
Livox Avia LiDAR		Livox Avia
CMOS		MV-CA013-21UC
Camera Len		MVL-HF0628M-6MPE
STM32		STM32F103C8T6
Screen		IPS Screen 14''
Battery		4800mah
TTL to USB		TTL to USB
TTL to 485		TTL to 485

The source code is released under GPLv2 license.

If you use any code of this repo in your academic research, it will be very appreciated if you can cite any of our following papers:

[1] Zheng, Chunran, et al. "FAST-LIVO: Fast and Tightly-coupled Sparse-Direct LiDAR-Inertial-Visual Odometry." 
[2] Hong, Sheng, et al. "Rollvox: real-time and high-quality LiDAR colorization with rolling shutter camera."