Show HN: DIY Position Tracking Using HTC Vive's Lighthouse

https://github.com/ashtuchkin/vive-diy-position-sensor

by ashtuchkin • 10 years ago

153 38 10 years ago

ashtuchkin13• 10 years ago

Hey, author here. I used the system described in the link for indoor stabilization of a drone, plus precise landing, to support an automatic battery swap station project (have a video there). Worked pretty well, so I decided to open-source it in hopes this would help fellow hackers.

Let me know if you have any questions!

detaro• 10 years ago

Awesome project, and especially awesome README file: good explanations and images!

If I read it right, a way to feed it position data is already integrated in the drone firmware, so you only have to send it the found coordinates and it uses them, correct?

ashtuchkin13• 10 years ago

Thanks!

Yep, I'm using Mavlink protocol (specifically ATT_POS_MOCAP message) to feed 3d position to the drone autopilot.

jskopek• 10 years ago

The hot-swappable drone battery video is cool enough to be its own Shown HN submission.

Would it be hard for the drone to be able to seamlessly switch between indoor/lighthouse tracking and outside/GPS tracking? How about the ability for the drone to orchestrate the battery swap autonomously with the charging unit? If you could add those two features you could produce a proof of concept video that would probably blow a lot of minds.

ashtuchkin13• 10 years ago

Thanks, that's nice to hear!

Seamless switching is definitely doable and shouldn't be hard, just need some time to implement. I'm using PX4 autopilot and it's very friendly for adding new functionality.

Orchestration is also close - in current demo both station and drone use Wifi to coordinate, so it's a matter of adding new logic.

Currently the most limiting resource for that project is my time :) I'd be happy if other people would want to join!

RobertLong4• 10 years ago

This is awesome!

Curious what your thoughts are on this vs one of the official SteamVR tracking modules[1] which use the TS3633[2]? For $10 this is an awesome hack for off the shelf components. However, for $70 + Shipping you can pick up 10 of the tracking modules which filter out noise and do accurate envelope calculation.

[1] https://www.triadsemi.com/product/ts3633-cm1/

[2] https://www.triadsemi.com/product/ts3633/

RossBencina3• 10 years ago

I'm not familiar with the SteamVR tracking modules that you linked, however from the link:

The CM1 contains all the circuitry necessary to convert SteamVR Tracking base station infrared light into a digital output that encodes the angle of the sensor from the base station.

That implies that it's not a full location tracking solution by itself (angle only). The data sheet[0] doesn't seem to shed any further (ahem) light. Maybe I'm wrong. And I'm certainly interested in learning more. Do you have more details on the SteamVR tracking system?

[0] https://www.triadsemi.com/download/16501/

ashtuchkin13• 10 years ago

Thanks! I actually haven't seen those, they look pretty good, basically replace the custom schematics I needed to build.

The timing calculation still needs to be done somewhere though, I wish there was a module that would do it internally and just publish the timing numbers - that would be more scalable and then even Arduino would be able to handle several sensors.

fest3• 10 years ago

Did you have any issues with PX4 interpreting and fusing MOCAP data?

ashtuchkin13• 10 years ago

I needed to make some adjustments and fix some bugs there to make it work. It has the code, but it didn't work great indoor. I'll try to send these changes upstream when I have time. Let me know if you're interested in them - I can explain further.

rebuilder• 10 years ago

Very nice work!

Do I understand correctly that a single sensor board as described here will get position, but can't get orientation?

If so, how does the drone handle orienting itself correctly to land on the battery swapping station?

70jS8h5L• 10 years ago

Onboard accelerometer/gyroscope which is part of the flight controller, most likely.

ashtuchkin13• 10 years ago

Yes you're right, only position. I'm using acc/gyro/compass on the drone.

RossBencina3• 10 years ago

Hi, I have some questions:

3d position accuracy: currently ~10mm; less than 2mm possible with additional work.

Could you outline what is required to take your solution from 10mm to 2mm accuracy? what factors limit maximum accuracy?

Presumably the lighthouse-derived position could be fused with IMU data for better temporal accuracy. Does your drone software do that?

Thanks!

ashtuchkin13• 10 years ago

The geometry calculation is currently approximate, not taking into account that the laser planes have ~3cm offset from center, that's one. Timing precision is probably the next one - microseconds might not be enough and we can measure better.

Currently std dev of each position coord in rest is 1.9mm.

Fusion with IMU is the next level and is usually done later down the line because it needs to be tuned for particular model. Yes, the drone does that.

SuperPaintMan• 10 years ago

I've been mulling a installation work based on exploring video solids[1] around using cheap phone-VR mounts. This project is exactly what I need to find the viewers position in the video/space. Any cheaper way to do this without the Lighthouse devices?

[1] https://theblackbox.ca/blog/vector-video/

ashtuchkin13• 10 years ago

Nice project!

There's a whole bunch of indoor positioning methods, having different precision/simplicity/cost profiles, so you might need to shop around. Probably cheapest and closest to my sensor is ultrasound sensors like http://www.marvelmind.com

moron4hire5• 10 years ago

I actually just arrived in Seattle to take the official HTC course on using the Steam VR positional tracking system, and this was one of the first things I saw as I got off the plane.

ashtuchkin13• 10 years ago

That's so cool :) let me know if I got anything wrong with the device or geometry calculation! Also I would be happy to get any feedback from Steam VR people!

fest3• 10 years ago

Great project! When listening to an interview with Alan Yates[0] (main designer of the Lighthouse) I was thinking about an application like this.

I recently did shop around for motion capture system (cameras tracking markers) and one of the cheapest systems with comparable performance to OP's came out to cost $5-8.5K.

[0] http://embedded.fm/episodes/162

ashtuchkin13• 10 years ago

That's crazy :)

thenomad2• 10 years ago

Fantastic!

Having been developing with the Vive for most of the last year for Left-Hand Path (http://store.steampowered.com/app/488760), and given I've got a lot of mocap experience before that, I can confirm that Lighthouse's tracking is ridiculously good.

It's not just as good as something like an Optitrack system: it's significantly better.

If this provides comparable tracking to what the Vive offers, it's an absolutely unbeatable price / performance combo.

ashtuchkin13• 10 years ago

I was really inspired by that too! The tracking is comparable, but not on par yet - you need multiple sensors and IMU fusion to achieve the smoothness of Vive. This is only a first step :)

thenomad2• 10 years ago

Ah, they're doing sensor fusion with inbuilt IMUs? That makes sense...

I have a colleague with some deep technical knowledge in this area - he's the guy who did the heavy lifting when I built an inertial mocap suit a while ago. I've pointed him at your project. If it turns out that it is of interest, perhaps you can get some useful collaboration / suggestions out of that!

emilburzo• 10 years ago

A bit off-topic, but I was wondering:

How was the base station visualization[1] done?

[1] https://camo.githubusercontent.com/d9241f231a03d177d215f98bd...

jaflo• 10 years ago

https://youtu.be/J54dotTt7k0

Show HN: DIY Position Tracking Using HTC Vive's Lighthouse

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