Hi,

Is there any github repo for this project? I'm trying to build a LiDAR by myself. It will be a good start if I would get a github repo for this project.

Is there a reason the code is not available? Are there PCB design files and a BOM for the Unruly LiDAR?

Any updates on this project?  Still a very interesting area, even if just limited to range finding.  Also have you evaluated different optical band pass filters to reduce background light on the APD?

Hi John. We've had to put this project on hold as we weren't able to get enough interest to justify the tooling costs. Very few people were willing to get involved in the software aspects of the project and this is where we had hoped to develop community spirit. We are leaving this project on the backburner for a while with the hope that as interest in Lidars continues to grow it might reach a critical mass that justifies more investment in time and money on this kind of project.

A big thanks to everyone who has offered their support. 

Just would like to let you know I have huge interest with LIDAR, learning verilog just for lasers and lidar. can help with anything. hell, ill even buy ur schematics and plans just so that I have a "decent" place to start a lidar project.

Is there any code for this application?

Interesting laser rangefinder: https://lightware.co.za/collections/lidar-rangefinders/products/sf22-c-100-m
It looks very similar to Unruly and produced by company mentioned here: https://hackaday.io/project/163501-open-source-lidar-unruly/log/159018-rev2-unruly-design-for-lower-cost

Similar but not open source!

I am with Simon.  What does rev3 look like.?   How well does it work?   How can the community get involved?

I am ready to try out a prototype when ready.  Please advise as I have a commercial project that could use this

@Laser Developer @Lincoln Wang and other #Open Source LiDAR - Unruly  team members, what's the latest on this project? I would like to see it come to fruition but would prefer to get behind a community effort, rather than see it fragment and the critical mass fail to coalesce. If it is stalled or has been wrapped up, is the team prepared to release any more of the design work done so far, or even discussion on the team chat log, so that others can take it further?

Hello, I think your project is very interesting. I want to build one, too. Could you please share the Eagle design files of your PCB? 

I'd like to experiment and contribute, but with my limited experience, I can't take what's given and turn it into a viable PCB, much less circuit python code.  Could the files for those be uploaded?

Would you be able to increase range of measurements taken by changing any of software or hardware settings? Taking multiple measurements would be acceptable too. I'm looking for upto 300m against a white/light background in sunlight. 

this should be a golf range finder, not lidar. google how laser range finder works.

@SmallDevices Please could you explain how this project is less suitable than a golf laser range finder? Genuinely interested as my Google search didn't make it clear to me. 

300m distance requires a more powerful laser source, but then we need to consider eye safety issue. Using laser with different wavel like 1550 nm is safer at higher power. But those laser are larger and more expansive.

Thank you @Lincoln Wang 

@Lincoln Wang As I know, most of the golf rangefinders have 905nm lasers. Can you give links to a golf rangefinder with 1550nm laser? Also, most of the golf rangefinders are using 75W laser, just like "905D1S3J09UA" laser used in Unruly.

300m with a lidar under $100 is not feasible. instead, use correlation/averaging tricks you can detect 300m distance （600m round trip) with cost down to $25. The response will be slow, say 10 to 100Hz.

That is plenty fast enough for me. What would need to be different in the HW compared to this unruly lidar?

The temperature control of the APD looks not simple. Did you implement PID control to the BIAS_PUM?

I am also trying to make a LiDAR with a scanner. 

Question: why you use a variable gain amplifier(VGA)? When you need to change the gain? Since I see use fixed gain amplifier might also work.

An annoyance that I think I'm going to start trying to combat: the capitalization "LiDAR". Nothing personal (or "projectal")—this is just the one where I finally decided to say something. Do you (and everyone) write RaDAR or SoNAR/SoDAR as well? I doubt it. And while this may not be the case for those two, I believe "lidar" was the capitalization used the very first time that acronym was used in print.

But this project looks cool, and I'm following it now :)

Thank you! I couldn't agree more. The acronym has been driving me nuts for a few years now but we can't seem to get away from it. In truth it should be LRF (Laser Range Finder) but a number of influential companies decided that LRF wasn't cool enough so they started using LiDAR and it has just stuck. A Lidar used to be a laser to measure atmospheric particles. Oh the complexities of language evolution...

This is a really interesting project- how long have you been working on this? What chipset are you using for amplification and how much noise is there?

Out of curiosity, how much is that APD?

We can buy in bulk for less than US$15. It is not available through the retailers but you can approach your local Hamamatsu rep directly for quotes. There are lots of other APDs that can also be used with the same control circuitry.

This is really interesting. I bought a LidarLite before they sold to Garmin. Then they became too expensive...

Looks like the v3 Garmin unit is about $150 £123.

How does yours compare?

We are getting a manufacturer on board and linking up with specialized distributors. To make it work we all want to have a retail price of US$99. This is still a challenge because we have no sense of the production volumes.

Very nice project.  One of the items mentioned was handling of multiple returns, which I assume would require either multiple TDCs or retriggering of the first TDC.  Have you come up with an approach for this?  Good work - keep it up!  John

Thanks John, we appreciate the positive comment.

TDCs usually allow for multiple returns but it depends on the manufacturer and the price as to what you get. The TDC in the Unruly was chosen because it accepts 5 stop signals for every start signal and each of these stops can be read directly by the processor.

This TDC is also in an easy to handle form factor (TSSOP) which means that we can get circuit boards made quicker and cheaper than if we had used a more complicated part.

1. Is this a true time of flight design?  I understand that there are different types of LiDAR such as those that depend on the phase of the returning light WRT the sending light.  I imagine such a scheme would only see the strongest reflection.  I imagine a true time of flight design would see multiple responses as the light bounces off complex objects.

2. LiDAR devices have always been expensive.  Are there design trade-offs where cost and complexity can be reduced along with precision?  But repeatability is retained? 

1. This is the real deal - direct time-of-flight. You are correct in saying that phase measurement LiDAR cannot easily discriminate multiple targets whereas the Unruly can detect up to five returns in each laser shot. Take a look at instruction #11 for an example of three targets.

2. One of the reasons for posting this open source design is to stimulate the development of more LiDAR products and thereby drive the component costs down. The Unruly should retail for well below US$100 and if we can get enough support it will go into production. There are many combinations of components that would make it cheaper but this is already a heavily optimized design. But maybe someone else can do better?

So "The analog signal is then converted into a digital signal using a comparator and this digital signal stops the TDC." means that the uP isn't doing the stopping?  (Well, that's easy to believe as we are likely talking nS of time here.)  So, if the TDC only had 1 stop it is likely that it would be wasted most of the time on noise and other false triggers?  But with more stops the uP could pick out the strongest return?  Is that the strategy?

Smart man! Yes, that is exactly correct. Real world sensors never have zero noise. In the case of a time-of-flight LiDAR noise is the main problem because the analog circuitry needs a very wide bandwidth to handle the "impulse" nature of the laser flash. This high bandwidth will let through more noise than say, a phase modulated LiDAR that runs with a very narrow bandwidth.

However...

Most engineers don't realize that you can fire the laser really fast without exceeding the Class1 eye safety rating. This means that you have tons of data to analyze (shots and stops) so it becomes a matter of simple statistics to discriminate between random noise and a deterministic signal.

To take the concept further, you can easily configure the Unruly to operate well below the noise floor (SNR << 1) and still pick up signals realiably (> 5 sigma certainty). 

- The limiting factor on update rate is the CircuitPython code. Using C will be 10x faster.

- Single measurement resolution is 55ps with some jitter making it about ±2 cm. 

- Most APDs will work including the AD500-8 (it's very expensive!). I have a meeting with Hamamatsu next week to discuss bulk discount on the S10341.

- There are different ideas about what bandwidth to use in a LiDAR. By changing capacitor values the Unruly has a practical BW limit of about 500MHz. I think that changing the BW to see what happens would be a great experiment.

- Yes, I will be publishing all waveforms and test data as soon as possible.

Thank you for your reply.
There are a lot of "AD500-8" sold on aliexpress.com for <15$ but I have doubts about theirs quality.