homebrew 360° – A cave is hard to measure with ordinary surveying tools, but [9nl] built a rotating lidar setup around an Ouster VLP-16 sensor to scan a full 360 degrees. The custom rig tackles the sensor’s 40-degree limit and turns data processing—and careful handling in and
Measuring the inside of a cave isn’t something you do by force of will alone. If you try to map it with classic surveying gear, you’re signing up for a lot of hard work. [9nl] chose a different route: a laser scanning rig built from scratch to capture a 3D view of the space.
The heart of the setup is an Ouster VLP-16 mid-range lidar sensor. It works by shooting out pulses of light and measuring how long it takes them to bounce back. which lets the system calculate the range of nearby objects—and. in turn. build 3D scans. For most tabletop or small-room scanning, that’s a straightforward path.
But [9nl] ran into a limitation: the VLP-16 only offers a 40-degree field of view. For the job of scanning a cave, that wasn’t enough coverage. The solution came in the form of mechanical engineering rather than a bigger sensor—[9nl] mounted the sensor on a custom rig that can rotate. effectively extending the scanning capability to a full 360 degrees.
There’s nothing wildly complex described in how the rig operates. The sensor is placed on a shaft, and a belt drive spins it through the full rotation. After that, the remaining work is processing the data correctly so it can be assembled into a usable 3D scan. In the cave itself. the technical challenge shifts from “can it scan?” to “can you bring the rig safely in and out without breaking anything?”.
Off-the-shelf 3D scanning solutions can also do this kind of work. but they “do this work” at a cost that can be hard to swallow. Building the setup yourself means you learn how everything fits together while tailoring the rig to the specific constraints of the environment you’re trying to measure. The trade-off is time and tinkering—exactly the kind of problem that turns a simple sensor specification into a real-world project.
A video is available after the break, showing the approach in action.
laser scanning lidar Ouster VLP-16 3D scanning homebrew engineering cave mapping robotics custom rig mechanical rotation