DIY Open Source LiDAR Designed Around an ItsyBitsy M4 Express

Building a homebrew LiDAR platform is no easy feat even for skilled engineers, but not so much for ‘Laser Developer.’ He’s “dedicated a lifetime to make LiDAR systems smaller and cheaper,” and has now detailed his Unruly Open Source LiDAR.

While the Unruly LiDAR uses some off-the-shelf-parts, the project is a rather complex build. The platform is designed around an Adafruit ItsyBitsy M4 Express and uses a pulsed laser diode (PLD) to produce a flash of light, a hypersensitive avalanche photodiode (APD) to detect the return signal, and a high-speed timer to measure the TOF on the return time. These are housed inside a 3D-printed enclosure outfitted with precision lenses and filters to give it the maximum range possible at the highest resolution.

Laser Developer’s LiDAR features a pulsed laser diode to generate a flash of light, an avalanche photodiode to detect its return, and a high-speed timer to measure the return time. (📷: Laser Developer)

It should be noted at this point that the Unruly LiDAR is still undergoing development, and as such, the feature set and software capabilities noted below are target goals.

As far as features are concerned, the Unruly’s measuring range can be adjusted to over 100m on natural surfaces, and up to 250m on reflective surfaces (sunlight only). The resolution can be configured down to 1cm, has a measuring rate of 1000 readings per second, and up to five different target returns can be measured on each laser shot.

3D-printed housing for PLD and APD sensors with optical lenses and filter. The M4 Express fits in the rear of the enclosure. (📷: Laser Developer)

On the software end, Laser Developer programmed the Unruly using CircuitPython and a basic text editor, and allows for a host of adjustment parameters- including laser power (pulse, width), APD adjustments to account for temperature and ambient conditions, amplifier gain adjustments for better SNR (signal/noise ratio), and detection threshold adjusted to account for false returns.

Laser Developer’s Unruly LiDAR is a lofty one, but if he manages to pull it off, it will be one of the greatest builds to date that makes use of the SAM D51-based M4 Express microcontroller. Those interested can follow the project log and build walkthrough on the link provided at the top of this post.

DIY Open Source LiDAR Designed Around an ItsyBitsy M4 Express was originally published in Hackster Blog on Medium, where people are continuing the conversation by highlighting and responding to this story.

Original article: DIY Open Source LiDAR Designed Around an ItsyBitsy M4 Express
Author: Cabe Atwell