Vive Trackers Experiments – Part 1: Everything you need to know about Vive Trackers


Today I host a new post by my friend and VR professional Rob Cole, who has already published many interesting posts on my blog, including a review of Pimax Sword controllers, a series of hack on how to modify the Valve Index, and his experiements in creating new innovative controllers for SteamVR.

Thanks to the support of HTC, Rob is experimenting with Vive Trackers, and is very eager to tell you everything about his experiments with them, in a series of two very detailed posts. This first part of the series will be all about Vive Trackers, telling you what they are, what they are used for, and what has been their history. The post finishes also with the little surprise of an interview with HTC’s Shen Ye. This first part is a bit more theoretical on the technology, while the second one, which will come in the upcoming times, will be more practical, with a deep hands-on with the experiments.

Have fun reading this first part!

Introduction

HTC Vive Trackers (Image by Rob Cole)

After purchasing my first HTC Vive virtual reality system in 2016, rumours soon surfaced of a SteamVR “tracking puck” that HTC had in development. Nearly a year later, during July 2017, I visited Sandbox in East London for the UK launch of the “Star Trek Bridge Crew” game on SteamVR.

Networked PCs allowed guests to try out the awesome new 1-4 player experience using a room full of HTC Vive VR headsets and motion controllers. The room was setup on 2 levels so it felt like being on the bridge, whilst for solo guests the software offered an “AI” crew to fill in the empty stations. Whilst waiting for my Bridge Crew session, I wandered downstairs and found Sandbox’s technology showroom, containing all kinds of cool tech demos and gadgets.

Bridge Crew (Image provided by Rob Cole)

Amongst the holograms, 3D printers and smart tech, I spotted a pile of boxed Vive Trackers with packaging designed for the Asian market. A printed notice informed me exactly what they were, who manufactured them, and that these were the first to arrive in the UK.

The industrial design was very familiar to anyone who had spent time using the Vive headset and Vive motion controller. If held side by side with a Vive Controller, it looked like the body of the controller had been chopped off leaving just the tracking head, smart thinking from HTC. 

Vive trackers at Sandbox (Image by Rob Cole)

The person staffing the showroom didn’t know anything about the Tracker as it was just one of many different items on display, but I was allowed to pick one up and photograph it.

It was relatively small but felt dense and looked well made with a high quality injection moulded plastic casing. The outer surface of the casing was pockmarked with optical sensor windows, whilst a centrally mounted Vive logo served as the power button.

Flipping it over, it appeared to have a threaded camera mount (commonly used for tripods) and some sprung “pogo pins” for electrical inputs. Finally, I noticed a micro-USB socket at the bottom of the Tracker for charging and probably also for firmware updates.

Vive headset disassembled (Image provided by Rob cole)

They also had a disassembled Vive headset, Vive controller and Vive base station on display, giving me a rare glimpse into the inner workings of this new SteamVR hardware. Overall a very cool afternoon: trying the Star Trek game and getting to see all the Vive tech… thanks Sandbox!

Since my visit to Sandbox all those years ago, there have been another 2 versions of the Vive Tracker released, aptly named Vive Tracker 2.0 (2018) and much more recently, the smaller Vive Tracker 3.0.

So what is a Vive Tracker?

Put simply, the Vive Tracker is a wireless, battery powered SteamVR tracked accessory that provides highly accurate, low latency 6 Degrees of Freedom (6DoF) motion tracking within a roomscale environment.

In HTC’s own words: “Track movement and bring objects from the real world into the virtual universe.”

Vive tracker attached to the hand (Image by Rob Cole)

The user feedback on this device has been great:

“VIVE Trackers bring a huge level of versatility to our platform, fully-tracked avatars feeling much more lifelike, virtual dancers performing the craziest breakdance moves in real time or educators building training applications with fully tracked props and mockup devices.” NeosVR

“The HTC VIVE Tracker is a huge part of our tool belt when it comes to the development of custom peripherals. We use the technology to create simple tracked objects, complex control panels, and integrated real-world tools. This lets us map physical buttons with a digital component for maximum immsersion in our experiences. Bit Space loves the trackers.” Bit Space Development

“With the VIVE Tracker, firefighters experience life-like feedback and feel the force of the hose, creating an immersive VR training that’s as real as it gets – without the risk.” FLAIM Trainer

“I use VIVE Trackers every day to transform into a bishōjo (beautiful girl). By syncing your body motions, your avatar will feel as if it is a part of your own body.” VTuber, Virtual Girl Nem

The Vive Tracker is available directly from HTC website as well as from a number of different electronics and gaming vendors. The current Vive Tracker 3.0 has a recommend retail price of £129 in the UK ($129 in the US) which includes free shipping. To use the tracker, users will require a SteamVR compatible PC, a Steam account (free of charge) and the installation of the SteamVR software. 

What is SteamVR?

SteamVR is a PC based virtual reality system (PCVR) developed by Valve Software, which was first released to the public during 2016 in partnership with innovative Taiwanese smartphone manufacturer HTC who launched the “Vive” PCVR system.

SteamVR system (Image by Valve)

SteamVR uses a proprietary motion tracking system known as “light house” or “base station” comprising of 3 components: base station, tracked object with sensors, and host X86 based PC.

SteamVR tracked objects can include the VR headset itself, a pair of hand held motion controllers or tracking pucks like the Vive Tracker. Each object contains special optical sensors which detect laser light from the base stations, an IMU and a small computer with 2.4Ghz wireless module that connects to the host PC. 

SteamVR tracking components (Image by Valve)

“The SteamVR Tracking Basestations sweep the room with multiple sync pulses and laser lines, reaching out to about 5 meters. By keeping careful track of the timings between pulses and sweeps, the SteamVR Tracking system uses simple trigonometry to find the location of each sensor to within a fraction of a millimeter.

By combining multiple sensors, 2 basestations, as well as adding a high speed IMU (inertial measurement unit), SteamVR also calculates the tracked object’s orientation, velocity, and angular velocity, all at an update rate of 1000Hz.” Valve Software

What is Vive?

Vive was a PCVR system from HTC using Valve’s “SteamVR 1.0” technology. It was known as “Revive” during development, then as “Vive Pre” for the developer edition, before launching an almost identical consumer version called “Vive” in April 2016. 

Sold as a full PCVR kit for £799, Vive required the use of a powerful gaming PC with the latest graphics card, quickly finding a hardcore following amongst early adopters and tech enthusiasts.

Vive was impressive, it only took a 20 minute demo with a Vive Pre before I was completely sold. I came back the next day and spent a considerable amount on a Vive and new graphics card for my PC. During the following months, numerous people got to demo my Vive, with many of them surprised at how effective the technology now was. 

Vive Pre headset (Image by Rob Cole)

Vive took the early market by storm, launching out the box with full roomscale support and tracked motion controllers, whilst Oculus could only launch their Rift CV1 with seated support and an Xbox game controller. Oculus didn’t actually add roomscale and tracked controller support until months later, with the release of their Touch controllers, and additional USB-connected tracking cameras. 

In the years since, Oculus have gained substantial consumer market share by selling what is reported as loss-leading hardware, underpinned by substantial amounts of cash from Meta in an aggressive long-term attempt to own the next computing platform. The Meta Quest standalone headset has been a huge success, bringing 6DoF VR to the larger consumer market who generally don’t have gaming PC’s.

In June 2019, Valve entered the hardware market themselves with their Index PCVR system, sold direct to consumers through Steam. Despite being $1000 for the full kit, it’s probable that Valve don’t make any profit from Index as it doesn’t need to; its all about getting people to buy games on Steam regardless of which hardware they use. The privately owned company is flush with cash from their 30% cut of all sales going through Steam, which means that R&D or RMA costs can be absorbed without feeding back into higher consumer pricing for hardware.

With Oculus making their long play and Valve directly entering the market, HTC soon realigned their sights on the more lucrative Enterprise market where its possible to actually make a profit from hardware. Consumers have signed up for HTC’s subscription based software access, whilst more recently HTC made an early move to start laying foundations for the Metaverse.

HTC is still offering headsets to consumers, though aimed at the Prosumer market, where it’s also possible to make some profit from hardware without going bankrupt in the process! Despite their partial withdrawal from the wider consumer market, HTC has done great business in the location-based entertainment market with targeted business support packages.

Vive trackers on a PC (Image by Rob Cole)

It wasn’t uncommon for me to attend a big VR event and find 60 Vive Pro Eye headsets being used across the site, or see 12 Focus headsets being used at a VR festival.

HTC headsets have dominated the majority of the events, promos and arcades I have visited since 2016, with the HTC wireless adapter, Vive Tracker and backpack PCVR rigs being used with Vive or Vive Pro at many sites. So despite the observation that HTC is no longer leading the consumer market, behind the scenes in the business world, they are doing good work.

HTC Vive software and hardware (Image by Rob Cole, using assets from HTC Vive)

“Vive” itself has now become HTC’s brand name for all things VR-related, so it’s being used for more recent PCVR systems like “Vive Pro 2” and “Vive Cosmos”, as well as standalone systems like “Vive Focus 3” and  “Vive Flow”.

It also used the name in its metaverse marketing as “Viverse”, though in the context of this article Vive is related to the SteamVR compatible Trackers. 

Vive Trackers physical features

These are the main components of every Vive Tracker:

Different parts of a Vive Tracker (Image by Rob Cole)

LED indicator – red/blue/green
Power button – on / off
Sensors – light sensitive diodes
(4.1) Standard camera mount, (4.2) stabilising pin recess,  (4.3) pogo pins and (4.4) friction pad

Hidden inside the Vive Tracker there are certain of electronics parts, common to SteamVR tracked objects such as:

18 x Sensors (Triad Semiconductor diodes)
small CPU (brains, doing some maths)
IMU (1000hz 9DoF tracking)
Battery (Li-Ion rechargeable)
Gas Gauge (controls battery)
Wireless module (2.4Ghz Nordic Enhanced Shockburst)
GPIO module (for connections)
USB port(for battery charging and firmware updates)

If you look carefully at the outside of the Vive tracker, you can clearly see the optical windows for the sensor diodes. With HTC these have become part of their industrial design language, whereas later SteamVR 2.0 equipment such as the Index headset and controllers, and Pimax Sword controller have subtle optical windows in their casings that are not as easily visible.

Optical sensors of Vive headsets (Image by Rob Cole)

It should be pointed out that the original Vive Tracker was nearly obsolete by the time it launched as the Vive Tracker 2.0 quietly replaced it only a few months later.  The new 2.0 (2018) model was designed to support HTC’s new Vive Pro headset with Valve’s new “Base Station 2.0” second generation light house tracking system.

Tracker 1.0 and Tracker 2.0 were visually identical, apart from the color of the power on “logo button”. Internally, Tracker 2.0 had been updated with the next generation Triad Semiconductor diodes and an electronics updates to support base station 2.0 compatability.

Have a look at how the Vive trackers changed since launch. I’ve listed the key details of each tracker here below, for you to read.

Vive Tracker 1.0

Vive Tracker 1 (Image by HTC)

Release date November 2017
18 SteamVR IR sensors (BS 1.0)
Tracking: SteamVR Base Station 1.0
Support for 2 base stations in single room
FOV 270 degree
99.65mm width
42.27mm height
Weight 89g
1500mAh lithium-ion battery
4 hour operating time
USB-Micro

Box Contents:

1x Vive Tracker Universal Tracking Puck 1.0
1x Micro-USB cord
1x 2.4 GHz USB Dongle
1x Dongle Cradle
Instruction Booklet

Vive Tracker 2.0 (2018)

Vive Tracker 2 (Image by HTC)

Release date April 2018
18 SteamVR IR sensors (BS 2.0)
Tracking : SteamVR Base Station 1.0 and Base Station 2.0
Support for 2-4 base stations in single room
FOV 270 degree
99.65mm width
42.27mm height
Weight 89g
1500mAh lithium-ion battery
4 hour operating time
USB-Micro

Box Contents:

1x Vive Tracker Universal Tracking Puck 2.0
1x Micro-USB cord
1x 2.4 GHz USB Dongle
1x Dongle Cradle
Instruction Booklet

Vive Tracker 3.0

Vive Tracker 3 (Image by HTC)

“33% smaller 15% lighter, 75% longer lasting battery (than 2.0)” HTC

SIZE comparison between 2.0 and 3.0 Vive trackers (Image by HTC)

Release date March 2021
18 SteamVR IR sensors (BS 2.0)
Tracking : SteamVR Base Station 1.0 and Base Station 2.0
Support for 2-4 base stations in single room
FOV 240 degree
79.0mm width
44.1mm height
Weight 75g
Lithium-ion battery
7.5 hour operating time
USB-Micro

Box Contents:

1x Vive Tracker Universal Tracking Puck 3.0
1x USB-C cord
1x 2.4 GHz USB Dongle
1x Dongle Cradle
Instruction Booklet

FOV comparison between 2.0 and 3.0 vive trackers (Image by HTC)

Clarification of compatibility (from Vive Support)

Does 3.0 tracker work with 1.0 base station?

Yes, you can use Tracker 3.0 with Base Station 1.0/2.0 and Tracker 2.0

Can you use 1.0 trackers with 2.0 base stations?

No, they are not compatible. SteamVR Base Station 2.0 has a different method of syncing. Use only the same versions of the base stations in your play area so that your setup will work correctly.

SteamVR 1.0 > SteamVR 2.0 tracking?

The first Vive tracker was built around base station 1.0 tracking to support the Vive Pre and Vive headsets, but this technology was soon superseded by Valve’s new base station 2.0 tracking with the launch of the Vive Pro headset and 2.0 compatible controllers. 

The new 2.0 base stations were built to reduce mechanical complexity by removing 1 of 2 motors, whilst eliminating the need for optical or cable sync by using coded laser sweeps and removing the omnidirectional blinker.  According to Valve, there is another advantage of 2.0 base stations tracking that I’d not previously heard about:

More compatible: base stations co-exist with your other IR devices and have better immunity from depth cameras and motion capture systems.

Four tracking base stations used in a room scale setup (Image by Rob Cole)

Additionally, base station 2.0 offered support for up to 4 base stations working simultaneously in the same playspace whereas base station 1.0 was limited to 2 base stations.

The use of 3 or 4 base stations allows an expansion of the playspace to a maximum of 10 M x 10 M whilst minimising occlusion from users bodies, which is very critical for glitch free tracking.

How do I attach it?

Using a standard threaded camera mount (1/4” screw with 1.27 mm pitch and stabilising pin) on its base, the Tracker can be attached to many different objects, including those unrelated to Virtual Reality such as robotics and  film cameras for motion capture.

Film production using HTC Vive Trackers (Image by HTC)

How do I use it?

It’s very easy to use the Vive Tracker. First of all, it needs charging using the supplied USB cable. This can be plugged into your PC, or any smartphone mains charger with a USB output. Charging is quick, about 1.5 hours from mains power, or typically around 3 hours if plugged into the PC.  Once charged, the user only needs to connect the wireless dongle to a USB port on the PC: the dongle sits into a small cradle connected with a long USB cable to allow the wireless receiver to be isolated from any electrical “noise” coming from the PC.

After starting SteamVR, users can “pair” the Tracker using the “devices” menu. The on-screen instructions make it very simple. When using multiple trackers, USB connectivity can become an issue, depending on the quality of your PC motherboard and its power delivery to its USB systems.

How is it used?

An important use for the Vive Tracker is to allow physical props to be easily brought into the virtual reality environment, with both HTC and several aftermarket manufacturers offering a line of plastic accessories including a tennis racket and a gun.

Racket and gun (Image by HTC)

Tracker compatible games allowed users to kick a tracked football, hit a tennis raquet or shoot a gun. Playing games like Arizona Sunshine with the tracked gun was certainly fun, something I experienced several times at a local VR arcade here in the UK.

Over time though, it seems that the high entry costs of buying a tracker and accessories somewhat limited the total number of sales into the consumer market. This is not unusual when selling gaming peripherals, which are always an expensive add-on; they can be massive success like Guitar Hero or something of a commercial failure like Microsoft’s Kinect.

The limited overall sales lead to the user base being too small to entice further developers onboard, and so games with tracked accessory support remain quite limited. The list below shows what I could easily find (there may be more..)

Vive Tracker compatible games

Island 359 (Image by CloudGate)

Island 359
Tornuffalo
Arizona Sunshine
Final Soccer VR
VRChat
Virtual Sport
Boneworks
Monster Awakens
Fit It
Beat Saber
Full Body RhythmVR
Mystical Mayhem
Hubris VR
Blade and Sorcery

How is it used?

Training

Trackers are widely used for training firefighters and police officers to allow water hoses and firearms to be safely deployed in realistic scenarios. Recently, tracked guns have been used for training security of school personnel about how to deal with an active shooter inside a retail store or on campus.

Firefighters training with VR (Image by HTC)

Location-based Entertainment

It was common to see early adoption of Vive Trackers and accessories in VR games arcades and at other location-based entertainment venues where more specialist interaction was required beyond the scope of the Vive “Wand” motion controller.

Despite the accessory business not seeing big sales from the consumer market and software support limited to a small number of titles, location based entertainment remains a great use case for tracked peripherals.

It’s not uncommon to see Vive Trackers bolted to all different kinds of accessories, some off the shelf, and some custom made. I’ve chosen to describe to you one of several experiences employing Vive Trackers that I have enjoyed. This one will be well known to gaming fans with Bandai Namco officially licensing the IP from Nintendo.

Mario Kart VR

We were lucky enough to have a Bandai Namco gaming centre in London, where Mariokart VR was the main draw. Suitable for 1-4 players, with players using a Vive headset, a steering wheel and 2 Vive trackers for tracking object interactions.

Trackers used in Mario Kart VR (Image by Rob Cole)

Vive trackers were mounted on special hand straps, these were quickly put on and adjusted to get a good snug fit, but not too tight as the player still needs to grip the steering wheel.

The Vive trackers performed a very important function for Mariokart players, allowing players to grab objects littering the track, and then use these objects to attack other players – all whilst following the twists and turns of the track, including a huge gap that caused players to find themselves suddenly airbourne in their Mariokart!

MarioKart VR (Image by Rob Cole)

The balance between driving using the wheel and using objects from the track made for a very hectic experience with a sense of controlled panic typical of Mariokart. The custom hardware and Vive Trackers added a huge sense of immersion it simply wasn’t possible to find at home, and both times we visited, it was always busy.

Though the experience was relatively short, it was a huge amount of fun whether playing or watching other players. Loud shouting and shrieking could be heard across the site, bringing other people to come and watch the spectacle. One of the best examples of Vive Trackers bringing a really special experience to the players.

Social VR

A more recent driver of sales growth for Vive Tracker in the consumer market has been the rise of “Full Body Tracking” which requires the setup of multiple Vive Trackers to provide the ability to track body movement in SteamVR with great accuracy.

When combined with a pair of motion controllers and the headset, this provides multiple points of tracking which is used to drive the skeleton of compatible body avatars in popular social media applications like VR Chat.

Full body tracking in VRChat (Image by Rob Cole)

The growth of popular social application “VR Chat” has undoubtedly driven increased sales of Vive Trackers, and brought new tracker competitors into the market such as Tundra Labs and Manus.  VR Chat has numerous, thriving communities and game worlds, the use of FBT and custom avatars allowing users to really explore alternate identities whether as a furry, robot or something else.

Thanks for reading this 1st part of my journey with Vive Trackers. The 2nd part of this article, due later this year, will focus on some practical experiements with the Vive Trackers, including:

Attaching it to bought objects
Attaching it to custom objects
A Fully Body Tracking setup used in VR Chat.

To wrap this 1st article up, I managed to snag an exclusive interview with HTC’s Head of Global Products, Mr. Shen Ye. I wanted to know more about the Vive Tracker, its origins and different version, as well as their plans for the future, and he was very kind in answering me.

HTC Vive Tracker Questions & Answers with Mr. Shen Ye, Global Head of Products, HTC.

Shen Ye (Image by Shen Ye)
Where did the Vive Tracker come from / how did it come about? 

We saw a number of people and organisations using the original VIVE Wands as trackers – they were attaching them to objects which they wanted to track in 3D space. It was a big cross-section of companies and use cases, from aeronautics through to film production.  

What was the design concept? Was it originally a single tracker, or always intended to be used in multiples for full body tracking? 

Once we’d seen how people were using VIVE Wands, we knew we could make a more compact and easier-to-mount design, so that’s where the Tracker project started. The initial use cases were not around full-body tracking, it was more like attaching it to a camera or objects to use as props in games. 

What type of problems were overcome during development? 

Because of the diversity in use cases, there are a number of things to balance in the product. Size, battery life and tracking coverage were the primary decisions. At the time it was tricky to find that sweet spot – the main aim is for great tracking so that’s a priority but there’s no point in having sub-millimetre accuracy if the device can only last for five minutes and is hard to attach. We went through a lot of design iterations.   

How do the pogo pins work? 

We’ve published information on this in the developer guidelines: https://developer.vive.com/documents/850/HTC_Vive_Tracker_3.0_Developer_Guidelines_v1.1_06022021.pdf 

What range of attachments did HTC provide? (I recall a tennis bat, for instance) 

We built a tennis racket and table tennis bat which worked perfectly with a variety of tennis and table tennis apps. We also had partners like Rebuff Reality and Hyperkin who built tracker accessories. We wanted to make sure the Tracker could be easily attached to objects. I even 3D printed a Darth Maul-style lightsaber for playing Beat Saber with Trackers. 

How well did 1.0 perform in terms of sales/uptake? 

We never publish sales figures for individual products, but given we’re now onto the third generation of the product – you can tell they’re still very popular.  

Who was buying it? (I.e. consumers, businesses, location-based services venues, …) 

It was a big mix. Any industry which could benefit from sub-millimetre accuracy, so we saw consumers who wanted to do body tracking or add their own props to games, we saw businesses who needed precision in manufacturing, industries like aeronautics where they were doing simulated exercises, LBEs for sure, film production and many more. 

What led to development of version 2.0? (Vive Pro) 

The popularity of the first generation, and we were also developing our VIVE Pro headset which had shipped with BS 2.0. It was perfect timing because VIVE Pro was going to be used by a lot of the same user base as Tracker 1.0 

How well did 2.0 perform in terms of sales? 

Again… we never publish sales figures for individual products, but given we’re now onto the third generation of the product – you can tell they’re still very popular. 

Who was buying it? Was there a difference in terms of users between 1.0 and 2.0? 

Pretty much the same groups but now there were even more of them.  

Did HTC see other companies making attachments for the Vive trackers? 

Lots and lots and lots. It was great to see how people adapted to implement VIVE Trackers for everything from entertainment to highly esoteric industrial uses.  

How much input/ feedback did HTC have from location-based entertainment/arcade venues? 

We always work closely with our end users – we listen to feedback during the existing product’s lifecycle, and often send prototypes/dev kits under NDA for some partners to try out and feedback on. Nothing we do is created in isolation in a lab, it’s all based on real-world insights and data.  

What led to the development of 3.0? 

Technology had progressed enough that we felt Tracker 3.0 could be significantly smaller, lighter, and have a better battery.  

What challenges were overcome as its smaller, lighter, and longer lasting? 

We had to do a lot of testing – it was largely the same challenges as we had originally but with a few additions, there’s probably more full-body tracking now than in the early days, so we had to account for that.  

HTC has a competitor now with Tundra Labs tracker, does HTC see this as beneficial for the SteamVR ecosystem? 

We love seeing innovation in XR, and we’ve worked closely with Tundra Labs in the past.  

What is the future of the Vive tracker? Will it always require lighthouse base stations? 

I’m afraid we can’t comment on our future roadmap. We did recently unveil our VIVE Wrist Tracker for VIVE Focus 3, which demonstrates that there are great ways to deliver accurate tracking without base stations.  

As a key player with Vive Pro 2 and Vive tracker 3.0, how does HTC see the development of SteamVR going forward? Does HTC have a good working relationship with Valve? 

We have a great relationship with Valve – we released two new SteamVR products in the past year. We can’t comment on behalf of Valve but we’re definitely excited about our role in the SteamVR ecosystem. 

Huge thanks to HTC for providing the Trackers, Mr. Ye for the very interesting interview, and of course my friend SkarredGhost for hosting my latest article. [You’re welcome, Rob, thanks to you for writing these long and detailed articles for my blog!]

Part 2 of this article will be released later this year, more soon…

Thanks for reading! Rob Cole

(Header image by Rob Cole)

The post Vive Trackers Experiments – Part 1: Everything you need to know about Vive Trackers appeared first on The Ghost Howls.

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