OpenTOFLidar Ditches Laser Range Finders in Favor of Conventional Optics

LIDAR is designed to take accurate measurements of objects at distances, which is done using lasers to hit a target and measure the TOF (Time of Flight) of the light that bounces back. The differences between the time and distances allow users to create 3D images of an object, which is widely used for autonomous vehicles and object creation with 3D scanners.

Generally, LIDAR units are on the expensive side, costing upwards in the thousands range. Still, electronics engineer Ilia Sam decided to make his own on the cheap for fast 2D scanning. Instead of using lasers, he chose to utilize conventional optics, which include CS and M12 camera lenses. Sam developed his OpenTOFLidar (Open Source Time of Flight Lidar) around an STM32F303CBT6 MCU and features a photodiode lens, TDC-GP21 TDC IC, BLDC motor and octagonal mirror, and a laser diode that is used as a start signal by the TDC chip.

According to Sam, the OpenTOFLidar offers 15 rotations per second, has a measurement frequency range of 10 kHz, an angular resolution of 0.5 degrees, and a scanning angular range of 230 degrees. The minimal distance for scanning comes in at five centimeters, and the resolution depends on distance and surface type. For example, a light grey wall at a range of 30 meters has a max distance values scattering at 3cm or 0.3%, while a distance of 20 meters produces values scattering at 13cm or 0.6%.

Sam has uploaded a detailed walkthrough of his OpenTOFLidar on his project page, complete with links to schematics and the code needed to get it up and running for those who would like to recreate his build.