Knuckles EV2: What's New

Learn about the changes and new features of Knuckles EV2

Introduction

Over the past year we've sent out a number of Knuckles EV 1.3 developer kits to VR developers. The feedback we received, along with the results of extensive playtesting across a wide swath of players, led to significant updates to the design.

While it's still recognizable as Knuckles, very little of EV 1.3 was left untouched:

• Improved industrial design and ergonomics
  
• Updated input set and layout
  
• Improved strap fit and feel for more hand sizes
  
• New sensors, enabling new interactions
  
• Improved battery life, USB-C charging port
  
• Added support for SteamVR Tracking 2.0

The team has been hard at work on these changes, and we are excited to share what's new with Knuckles EV2 with the VR developer community.

Industrial Design and Ergonomics

With EV2, Knuckles has been modernized and updated with a new design. From a form and function perspective it keeps everything that made EV 1.3 great and improves upon it.

• The tracking fin now provides better tracking, and there's more room for larger hands around the handle.
  
• The handle has been sculpted to be more comfortable for a wider range of hand sizes (we are targeting hands in the 5th to 95th percentiles).
  
• The strap can now be adjusted for different hand sizes, and it's made with an easy-to-clean anti-microbial material.
  
• The top input surface has been reconsidered to ensure that both small and large hands can access all of the inputs.

Thumbstick and Track Button

Thumbstick

Unsurprisingly, one of the loudest bits of feedback we received from developers was around inputs - specifically Thumbsticks. There are definitely benefits to Thumbsticks over Trackpads when performing indirect interactions, like return-to-center force feedback. When controlling a third-person character, vehicle, or yourself, having this persistent feedback is valuable - especially when your vision is obstructed.

While one of our main goals with Knuckles is to enable great direct interactions, we know that indirect interactions in VR cannot be disregarded. And so we made room for a Thumbstick in Knuckles EV2.

Track Button

With EV2 we're introducing another new input - the Track Button. This thumb shaped groove takes the best parts of the old trackpad and distills them:

• It can be "the big button" for your game
  
• It's a natural place to rest your thumb
  
• It's still a trackpad - detect thumb 'Y' position (and a surprising amount of 'X')

In addition, the new Track Button is not actually a mechanical button. Instead, beneath its surface, there is a force sensor. This means that the controller (and content) can detect a range of force, from a light touch to a full press, expanding its capabilities beyond a simple mechanical button. We're excited to see what developers will do with this new input - more on this in a second.

Cap Sense

Since we shipped EV 1.3, the team has been hard at work updating the finger tracking capabilities of Knuckles. Several software updates later, we have auto-calibration and much higher fidelity finger tracking. EV2 takes advantage of all these software improvements while updating the underlying hardware to allow for even more advances in future updates.

In addition to finger tracking along the grip and trigger, all of the buttons, the track button, and the thumbstick have cap sense capabilities. This additional layer of input allows for higher fidelity thumb tracking, and is available for developers to utilize in their content.

Finger tracking is now accessed through SteamVR Skeletal Input. Knuckles estimate finger positions and then passes that data off to the driver which interprets that into 31 bone transforms. This can be used to much more deeply engage the user with whatever virtual reality they are currently experiencing. For more information about SteamVR Skeletal Input, view this blog post.

Force Sensors

With Knuckles EV2, we are adding force sensors to the list of inputs developers can utilize. These sensors are in two places - beneath the Track Button, and in the Grip 'saddle' area.


These force sensors allow for a much wider range of potential inputs:

• Analog - Detect a ramp of pressure from a light touch to a hard squeeze
  
• Digital - Both the Grip and the Track Button can behave as a digital input. Simply choose a force threshold for activation and fire a haptic to mimic the behavior of a mechanical button
  
• Multistep - Combination of the above
  
• Disabled - if your content does not need this functionality, this sensor can of course be ignored.

This will give developers the ability to map much more direct interactions and behaviors to in-game actions - like grabbing, pinching, crushing, charging, activating, equipping, and more.

In addition, the force sensors can be used in conjunction with capacitive sensors to enable higher fidelity interactions. With these two sensors working together, we can detect the full range of the hand position - from completely open, to holding the controller lightly, to gripping it tightly. This helps us understand user intent and makes things like "pickup and throw" with Knuckles EV2 much improved. We're excited to see what developers will do with this new capability.

Adjustable Strap

As mentioned above, the strap has been updated in several ways to accommodate a larger range of hands.

The top of the strap can now be adjusted to one of four positions around the rim of the input surface. This is to allow for different size hands and different length thumbs to reach the inputs comfortably. To learn more about adjusting the strap to best fit your hand, see the Quick Start guide.

The strap has a semi-rigid plastic insert that conforms to the back of the hand - acting as a guide to place the hand in the proper position, and also to provide greater surface area to prevent slippage. We believe this is a great upgrade from the previous strap, both in terms of comfort and ergonomics.

Battery Life

We've increased the battery capacity with Knuckles EV2 controllers, and they now have up to a 6 hour battery life.

These controller charge from a USB Type-C connector at up to 900mA, and they take about an hour and a half of charging to reach full charge (when using a dedicated USB charge port).

Knuckles EV2 Content

As of this post, there is only one piece of content that takes advantage of all the features of Knuckles EV2, and that is Moondust. This content was created while we were developing Knuckles EV2. It's been crucial to testing and vetting our ideas, and has proven to be a great way to introduce new users to these controllers.

Knuckles EV2 developers, you can add the Moondust Demo to your Library here.[http//steam] Look for SteamVR Knuckles Tech Demos in Library > Games.

Take a look and try things out - features specific to Knuckles EV2 are highlighted and demonstrated with this content.

• Crush rocks using the new force sensor
  
• Drive moon buggies using the new thumbstick
  
• Piece together a space station with your fingertips
  
• Prime grenades with a squeeze
  
• Throw objects naturally using a combination of force sensors and cap sense

To learn more about Moondust and what the developers learned while creating it, visit this guide, or watch this video.

In addition, you should try your other favorite games in VR. Some will work right off the bat, and some may require some tweaking. With the update to SteamVR Input, you can go in and adjust the button configurations for Knuckles. Don't forget to share your configs on the workshop!

As for your own content, please update to the new SteamVR Input system - this will make editing bindings across all current and future controllers (including Knuckles) that much easier. For details, view our OpenVR SDK 1.0.15[github.com] page and the documentation[github.com] to see how to enable native support in their applications.

Knuckles EV2 Documentation

Use these guides to get started with the Knuckles EV2 Dev Kit and learn about its capabilities.

• Knuckles EV2: Quick Start - Learn how to set up and start using your Knuckles EV2 Dev Kit.
  
  
• Moondust: Creating Content for Knuckles EV2 - Developer notes and lessons learned from creating content for Knuckles EV2.
  
  
• Throwing Mechanics with Knuckles EV2 - Learn how we came up with the algorithm for throwing using both the cap sense and force sensor features of Knuckles EV2.
  
  
• Knuckles, Unity, and SteamVR Input - A tutorial from one of the developers of Moondust on how to use the Unity plugin with SteamVR Input. (We have also been working with Unreal to update their SteamVR plugin to the new input system. Stay tuned for more news)

Next Steps

So what now?

If you received a Knuckles EV2 developer kit, please try out and use the new controllers. See above for information about demo content and guides for developing with Knuckles EV2.

Please take this content and documentation and think about out how your existing content can be updated to take advantage of the new inputs. In addition, think about potential future content that would be great with Knuckles.

The Knuckles team will be available on the discussion boards, which are private to Knuckles developers. Please use this as a space to ask questions, share observations and feedback, and learn from each other.

If you're a developer interested in participating in the developer kit program, you can apply on the Steam Partner page. Log in, and look for "VR Developer Kit Request" along the right side of the page.

[the viking]

So exciting, can't wait until they're available for purchase, even if for beta!
If there were a mobile palm grip plate, a cam could be used to adjust it's spacing/angle making the user feel like there was something filling their grip... this could be used as feedback so a user knows when they made contact, as well as to help gauge necessary grip strength to continue holding the object, and to create a jostling effect upon impact. (Making it so it flips upside down before reseating flat would emulate dropping something, but probably be too challenging)
A second cam inside the separated grip section could change the angle of part of the grip as it extends allowing for ergonomic contouring at the new angle.. put a thick silicon layer over it, and the user will never know it's two plates ;-)

[chatcat]

언제쯤 정식으로 발매되나요?
official release date?

[Ashran]

Any official release date? :/

[Piratebunny]

Can't wait for these to be ready. Hopefully soon and hopefully lots of developers jump on board.

[Zaela Zhezzaia]

I wish they would bring back the knuckle one controller. Give players an option to buy the first one or the second one. This controller is bad for people with disabilities in our hands. There a reason why Microsoft brought out special controllers for us disable people. That lack joysticks.

[tommosaur]

@Fem_Fox: On battery life: I feel like with how much longer it seems on the knuckles, that's a duration where with pauses every few hours, one could put them a bit on charging during those breaks and get through a long playing day.
Still, yeah, i'd prefer swap-able batteries/ battery packs in future iterations, too.
Comparing battery life to the oculus touch doesn't make sense to me, the tracking on the vive and rift is done differently with different pros and cons.
The Rift uses external cam tracking, so most of the positional tracking is done by the cams and software on the pc.
Whereas with the vive the lighthouses emit infrared pulses which the controllers pick up, so they do more on their end.
That leads to the vive having the most precise tracking and also allows full roomscale tracking with less dead zones and with only two lighthouses needed whereas with the rift 3 cams for roomscale, but that is likely the reason why it uses more power, to interpret the infrared pulses.

[Marshcar]

That battery life is a big letdown, I get 24hrs of usage from one double A on my touch controllers, also integrated batteries are a pain to replace. You should really go for interchangeable batteries.

[tommosaur]

you're welcome and yeah, can't wait, too =)

[TheTopMostDog]

@tommo
Cheers for the feedback. Yeah, I guess trying it in hand would quell my concerns. Just a matter of waiting, now.

[tommosaur]

@TheTopMostDog: i wouldn't worry about that at all. It's not important whether it's on the outside or inside, it is way more important what the angles and distances are your thumb has to be at/move to reach things and it looks like it is a natural angle at close distance, so it should be fine.
When you look at the oculus touch controller it has the sticks at similar (more "outside") positioning and that is like the most comfortable controller i ever held so far (way more comfortable to hold than both PS and Xbox controllers).
To me the knuckles look very much like a natural progression on those and so they look like they should be super comfy to hold to me from the videos and extrapolating on controllers i already held. I'd say let's give them the benefit of doubt at least until trying them, they are obviously doing testing to see how comfy it is to reach different parts for different hand sized users, so i'm pretty sure it should feel nice =)