After being a VR game anchor for a month, in addition to becoming more and more addicted to “Half-Life: Alyx”, I am still thinking about another question: what is the current VR?
As a “people in the middle”, I will use avatars to explain during live broadcasts – I believe that if there must be a virtual world in the future, we must be “deeply bound” with our digital avatars. This binding is not only external cognition, but also the experience in the real world and the virtual world should be common.
Players know that VR games have a very different experience than traditional games. In a VR game, you don’t have to sit in front of a computer and fiddle with a mouse and keyboard. You can really use the two-hand grip as a gun, aim at the enemy, pull the index finger and press the trigger, and today’s VR games can recognize finger movements very accurately – but you can’t pick up a dropped bullet in the VR world folder.
Occasionally, when I was hanging out on YouTube, I saw that Lucas (the founder of a VR startup team in the United States) made a VR haptic glove, focusing on the cost of all parts, he only spent $60.
I applied for reprinting this video to my account, and I didn’t expect the response to be overwhelming. Adding Lucas’ quote “You can really touch anything with it” added to my curiosity. Following the clues, I found an open source tutorial on GitHub, and I am ready to make a pair.
Parts to buy丨Photo provided by the author
With current technology, I’m not expecting “touch-to-anything” VR peripherals. But that’s what struck me. At present, in the VR market, apart from one headset and two controllers, there is nothing new. I think any attempt to expand the user experience at a “civilian price” is worth a try.
Touch virtual in the cheapest way
In 1987, when it was still the era of Nintendo’s red and white machines, gloves had already assumed the function of “input devices” as peripherals of somatosensory games.
Power Glove丨YouTube”Gaming Historian”
In reality, if you want to touch the gun in the game, in addition to letting the computer recognize that your hand is moving, model the virtual hand to move synchronously with the real hand (signal input function), and wait until the virtual hand holds it. When the gun is fired, a signal is returned – this signal acts on the hand, which is what we often call force feedback.
Meta has released a video of the tactile glove, which uses microfluidics technology and uses pneumatic actuators to create precise pressure by inflating and deflating air bubbles. To that end, Meta says it is also building a high-speed microfluidic processor. When Zuckerberg, who was “all in” in the Metaverse, finally brought out something, another tactile glove developer, HaptX, said, “Meta copied us!”
Meta has been developed for seven years, and HaptX has been developed for ten years. We do not know who copied who, but for sure, it will take many years for VR-related technologies to mature (at least in terms of price accepted by ordinary users).
How to implement force feedback at “extremely low cost” excites me. When I flipped through the tutorials, I found that LucidVR used a particularly “tricky” way. If Meta and HaptX make every inch of your hand skin a force point, the LucidVR glove only feeds force back to your fingertips.
Fix the drawstring on the finger丨Photo courtesy of the author
Simply put, the moment the object is about to be grasped, the finger should be pulled immediately to prevent further bending. Because the bending range is different, it means that the size and shape of the object “holding” in the hand are different. Controlling the way the fingers can’t continue to bend is to give the fingertip a “reaction force”.
Force on the fingertips丨Photo courtesy of the author
Therefore, the main part of the glove is a “main gate”, which extends out five pull ropes that are wrapped around the fingertips, and can be stopped at any time.
The servo is connected to the potentiometer. When the axle turns to the (servo) limit, the steering wheel will block the screws on the axle, so that the axle cannot continue to rotate, and the pull rope cannot continue to unfold. 丨Photo courtesy of the author
Now that I know how force feedback works, I need to figure out when and how to “close the gate.”
“When” is well understood, which is the moment when the virtual hand touches an object in the virtual world. Therefore, we need to make a medium, so that the action signal of the organism and the electrical signal of the computer can be converted into each other and “understand” each other. This is also the most ingenious design of this pair of gloves in my opinion.
The rotary potentiometer (the principle is similar to the sliding rheostat in the junior high school textbook) is connected with the pull rope. When the finger is bent, the five pull ropes drive the five potentiometers respectively, and the length of the pull rope is converted into the resistance value of the potentiometer. The changes are passed to the virtual world for analysis.
The sliding rheostat on the textbook丨The picture comes from the Internet
There are also other implementations based eg on IMUs (Inertial Measurement Units) or bending sensors on the modeling “data glove”. The so-called inertial sensor is a device that measures the three-axis attitude angle and acceleration of an object. It generally includes a three-axis gyroscope, an accelerometer, and a magnetometer to perform multi-sensor data fusion to reconstruct the three-degree-of-freedom direction of each finger. The bending sensor is better understood. When the finger bends, the physical deformation occurs to change the resistance of the sensor.
Comparing the prices of bending sensors and potentiometers丨The picture comes from Taobao
The two pass data is obviously more accurate, but why not? There is only one answer: more expensive.
The potentiometer and the pull rope are “connected” with the help of 3D printed axles丨Photo provided by the author
Find out when to “close the gate” and how to “close the gate”. Obviously, the pull cord needs a device that “stucks” it during its extension and retraction. I followed the tutorial and bought the MG-90S, a common steering gear in model aircraft, which is also very cheap at 10 yuan.
MG-90S steering gear with a wide range of applications丨The picture comes from Amazon
After doing it for a month, I only picked up a wine bottle in the game
After reading the tutorial, I quickly grasped the principle and said to myself, this “seems” quite simple? Isn’t that first, then this, and finally that?
I immediately ordered all the parts on the e-commerce platform, which are some common tools in life. There is only a part of ready-made products that cannot be bought (the skeleton that assembles each module), I solved it with a home 3D printer based on the open source component parameters.
Of course, you can also find Universal Taobao to play on behalf of the author. Photo courtesy of the author
Then, this is a month… At the same time, I have a deep understanding of another meaning of “quirky” is “not perfect”.
When I put on the ready-made haptic gloves, adjust the position of the Valve Index (VR headset), and start the game “Half-Life: Alyx”. I was in the familiar “City 17”, took out a pistol from my backpack, aimed at the wine bottles scattered on the street, “Bang!” At the moment when the shot was fired, I thought there should be a recoil. In fact, it was only my index finger that got pulled the moment I pulled the trigger – an experience that was more “plastic” than ballooning in the park.
But I should be successful! I replaced a wine bottle scattered on the street, “held” it in my hand, I could roughly “touch” it, it was a cylinder.
The use effect in the game丨Photo provided by the author
I found the problem when I wanted to use them more flexibly.
The first is the “recognition accuracy” problem. We need to understand that positioning tracking and local tracking are two concepts. The overall positioning tracking of the glove can be achieved by attaching Vive Tracker and Oculus handle, such as ready-made tracking technology.
The local tracking of fingers is the focus of a force feedback glove to solve. When I assembled it, I found out that this glove is not designed with sensors attached to each knuckle, and the bending state of the fingers can only be roughly modeled by the resistance signal converted by the pull cord (Lucas may have designed a set of software for this) , not accurate enough for every joint.
Hand tracking丨Photo courtesy of the author
Then there is the issue of “recognition range”. Also because of the simple structure of the glove, my fingers can only be recognized when moving up and down, and other degrees of freedom such as left and right expansion, rotation, etc. cannot be realized. But Lucas told me he’s already working on that, and the next version of the glove will have more freedom to unfold left and right by adding a potentiometer at the first knuckle.
Whether the identification is accurate or not will affect the effect of force feedback. Another factor is the adjustment of the limit position. The different bending degrees of the fingers correspond to the different limit positions one by one, which drives the steering wheel to turn to different angles, and then acts on the pulling rope that is being stretched.
In my understanding, this can be achieved because the LucidVR system presets this “correspondence”.
However, everyone’s hand conditions are different, and it is necessary to perform “personalized” calibration of the limit before use. If the adjustment is too tight, the hand will be pulled before grasping the object; if the adjustment is too loose, it will be like making a fist with an empty hand.
There is no easy way to do this, but when wearing the headset, you can feel the tightness and “estimate” the limit position.After taking off the headset, unscrew the servo screw, adjust the steering wheel, and so on, until it happens to grab the object in the virtual world.
Constantly debugging the limit position丨Photo provided by the author
In addition, prolonged stretching will cause the drawstring and gloves to deform. Since the whole set does not fit completely on the hand, but sticks to the glove, slight displacement of the glove will also cause errors in the force feedback.
The optimization experience can’t stop! Can be modified, can also be brainstormed
Before the gloves are actually used, there is a small episode.
After I have debugged it many times, the servo still remains motionless. I ran to Discord for help, and netizens told me that it wasn’t that the servo cable was wrongly connected to the development board, but that the current was too small to carry the servo. I need to connect a new power bank to the servo separately instead of sharing a power bank with the development board.
LucidVR’s Discord group has 14,000 followers. Some people improved this pair of gloves and replaced the drawstring with a tougher plastic sheet to solve the problem of easy deformation of the drawstring.
Some people directly change the structure and make an exoskeleton shape, leaving room for more sensors. Many open source projects will not cover everything, on the contrary, they will leave a lot of “blanks” for technology enthusiasts to explore on their own.
Exoskeleton Edition丨Photo courtesy of the author
In his demo, Lucas portrayed the gloved VR experience as exciting. In Half-Life: Alyx, you can pick up a soda can, throw it out, walk to the car, open the door to get in the car, and even climb a wall to escape when in danger. However, this is more of a “brain supplement” brought into other sensory experiences. At most, you will experience resistance against a wall, and there will be no feeling of climbing up against gravity.
Knowing this, when I put on this glove for the first time, I felt whether the object was big or small, round or square, even if it was just the stiff “touch” from my fingertips, it still made me feel novel. Before this, I couldn’t even imagine “emptying” a glass bottle.
Almost at the same time as making the gloves, I made my own SlimeVR full body tracker. “Similarly” with gloves, I made five sensors and tied them to the ankles, thighs, and waist respectively (because the SlimeVR software did not model the upper limbs). The five sensors first recognized the absolute position through T-pose reset, and then passed Each other” recognizes the relative position and parses the electrical signals into the movements of the virtual human. With this pair of gloves (handles) and head-mounted display, you can make the “old two-dimensional” dance happily in VRChat.
SlimeVR will also open source the code丨The picture comes from SlimeVR
A few months ago, I posted a video I made online and gained random followers. Of course that’s not what excites me the most. Two months after the release of the “SlimeVR Whole Body Tracker” video, the most important part, the BNO-080 (nine-axis sensor module), has risen from 90 yuan to 300 yuan on Taobao. (Before this, no one taught the self-made SlimeVR full-body tracker, so let’s assume that I inspired the love of the old two-dimensional people.)
Sensor module丨Photo provided by the author
Of course it wasn’t all “compliments” that I received. I 3D printed a model that would fit a small fan and hooked it up to the headset to solve the sweltering problem.
Homemade VR headset fan丨Photo courtesy of the author
But this time, because the fans used were too cheap, my solution was ridiculed for making too much noise – “like an airport”.
Posted by:CoinYuppie，Reprinted with attribution to:https://coinyuppie.com/i-made-a-pair-of-metaverse-gloves-that-cost-300-yuan/ Coinyuppie is an open information publishing platform, all information provided is not related to the views and positions of coinyuppie, and does not constitute any investment and financial advice. Users are expected to carefully screen and prevent risks.