Dexmo

Dexmo
Basic Info
VR/AR	Virtual Reality
Type	Haptic gloves
Developer	Dexta Robotics
Manufacturer	Dexta Robotics
Announcement Date	October 2014 (Kickstarter campaign)
Release Date	2017 (Development Kit 1, small batch); 11 June 2019 (Enterprise Edition orders opened)
Website	https://www.dextarobotics.com/
Versions	Dexmo Classic and Dexmo F2 (2014 Kickstarter, cancelled); F5 prototype (2015); Development Kit 1 (DK1); Enterprise Edition (2019)
Tracking
Tracking	11 degrees of freedom of finger motion per hand; position and orientation from an attached Vive Tracker or tracked controller
Connectivity
Connectivity	2.4 GHz wireless link to a USB dongle (DK1, maximum range 5 m)
Battery Capacity	1800 mAh LiPo per hand (DK1)
Battery Life	5 hours per hand (DK1 specification table)
Device
Dimensions	155 x 100 x 45 mm per hand (DK1)
Weight	About 300 g per hand (DK1); 290 g (Enterprise Edition)
Sensors	11 rotational sensors per hand
Input	Finger motion capture with force feedback on all five fingers

Dexmo is a wireless hand exoskeleton made by Dexta Robotics, a company based in Shenzhen, China, that captures finger motion and applies force feedback to the fingers so that a user can feel the size, shape and stiffness of objects in virtual reality. Each unit sits on the back of the hand and links to the fingertips through rods; rotational sensors in the joints track 11 degrees of freedom, and per-finger motors resist finger movement when the virtual hand touches a virtual object.

Dexmo began as a personal project of Dexta founder and CEO Aler Gu (Xiaochi Gu). A 2014 Kickstarter campaign with a US$200,000 goal was cancelled after raising just over US$55,000. Dexta later moved from on/off braking to variable force feedback. It distributed a small batch of the Dexmo Development Kit 1 in 2017 and opened orders for the Dexmo Enterprise Edition, aimed at industrial training, on 11 June 2019. Dexta has not announced a retail price and says the unit price varies by customer.

Reviewed 13 October 2026. Checked the Kickstarter, 2015-2016 prototype, CHI 2016 paper, patent, Red Dot, DK1 manual, 2019 Enterprise Edition and website claims against each cited source. About review dates.

History

Origins and the 2014 Kickstarter

According to Dexta, the first Dexmo was machined, silver-welded and hand-made from brass before the design moved to 3D-printed parts and later to mass production. Road to VR's 2016 timeline from the company dates the start of the project to October 2013 and the first "switching force feedback" concept, with a US patent filing, to June 2014. Gu's US patent for a "hand motion-capturing device with force feedback system" was filed on 14 August 2014 and granted on 17 May 2016 as US 9,342,151. It describes a base with a microcontroller, sensor modules for the thumb and four fingers, link rods to each digit, and locking mechanisms that resist finger motion.

Dexta launched a Kickstarter campaign in October 2014 with a US$200,000 goal. Road to VR described the company as a Chinese startup founded in March 2014 that had built about 17 prototypes. The campaign offered two models:

Model	Function	Kickstarter pledge price
Dexmo Classic	Input only; captures 11 degrees of freedom of hand motion, including three for the thumb and the splitting and bending of the other four fingers	US$75 single, US$150 pair
Dexmo F2	Classic functions plus on/off force feedback on the thumb and index finger	US$179 single, US$319 pair

Sources: Road to VR (pledge prices); Dexta product page, 2016 archive (functions).

On the F2, Dexta added a "force feedback unit" to the thumb and index finger linkages, which it described as a miniaturized gear disk braking system: when the user's avatar hit a virtual object, the SDK sent a signal to small actuators that braked and locked the joint. Neither model tracked the hand's position in space, and Dexta suggested pairing them with third-party trackers such as the Sixense STEM. The company cancelled the campaign in early November 2014 after raising just over US$55,000. It said it had reviewed "feedback from the VR market" and would "reboot it at a better time", with a next generation promising better responsiveness and possibly gentler force feedback. Gu later told Road to VR that the 2014 demo was only a concept, that backers expected a finished product, and that delivering one would have needed "way more than $200k".

F5 prototype and variable force feedback (2015-2016)

In August 2015 Dexta showed a new iteration in a video with an Oculus Rift demo. The company claimed 60 fps optical hand position tracking, supplied by its partner Depth-VR, with latency under five milliseconds. It also showed an F5 prototype with on/off force feedback on all five digits, while saying it was working on "variable stiffness". According to Dexta's timeline, variable force feedback was proven in June 2015, force feedback units were batch-manufactured in February 2016, and the SDK and Unity demos were finished in June 2016.

In a May 2016 guest article for Road to VR, Gu described two approaches: a binary system in which slider mechanisms lock and unlock the finger joints, and a variable-stiffness design in which a motor acts as a spring whose stiffness is adjusted in real time through impedance control. He wrote that the team had miniaturized the binary force feedback module on each finger, designing custom servos in the process. The binary design was published at the ACM CHI 2016 conference in San Jose in May 2016, in a paper by Gu (listed with both the University of Cambridge Department of Engineering and Dexta Robotics), four Dexta Robotics colleagues and Cambridge human-computer interaction researcher Per Ola Kristensson (see Design and hardware).

Dexta showed the variable-force version in August 2016. Road to VR reported that it was wireless over NRF radio modules (Gu said Bluetooth and Wi-Fi were "too slow"), weighed slightly more than an iPhone 6 Plus, and could "ideally run over 4 hours" on a charge. Dexta claimed 25-50 ms of input latency. For position tracking, the demonstration strapped two HTC Vive controllers to the underside of the user's arms. Engadget reported that only a single batch had been made. Gu was seeking software developers and VR/MR industry partners before a wider launch and told the site that "selling Dexmo is different than selling consumer electronics because you can't use Dexmo right out of the box." In September 2016 Dexta presented the Dextarity Interaction Engine (DexIE), a set of developer tools and algorithms for haptic interactions such as button clicks, object weight and object size.

Development kit and Enterprise Edition (2017-2019)

Dexmo won a Red Dot Award for product design in 2017. The award entry lists Dexta Robotics Inc. (Elko, USA, and Shenzhen, China) as manufacturer and Hefei XIVO Design as the design firm. Dexta distributed a small batch of the Dexmo Development Kit 1 (DK1) in 2017 and says it began shipping the development kit, with SDK support for mainstream headsets, in 2018. The company also reported an angel round of more than 10 million yuan from Grainsvalley Ventures and Sunwoda.

On 11 June 2019 Dexta announced the Dexmo Enterprise Edition, saying it was in mass production and could be ordered directly. The company described it as five motors, 11 rotational sensors, a rechargeable battery and a control system in one 290 g body, and said that it had gone through more than 50 iterations since the 2014 prototype. It showed the product at SIGGRAPH 2019. Dexta's website lists a Developer Edition for universities, companies and research institutes, an Enterprise Edition for commercial users such as VR arcades and training simulation, and a Consumer Edition still under development with no set price.

Design and hardware

Mechanism

The CHI 2016 paper describes the exoskeleton as a main controller on the back of the hand, force feedback units, upper and lower connector bars and finger caps forming a link-bar mechanism, with an extra linkage for the thumb. Each force feedback unit contains two rotational sensors and a micro servo that drives two stopping sliders to lock a ratchet wheel. When the software detects a collision between the virtual hand and an object, the units lock the joints and the exoskeleton becomes a rigid body that stops further finger movement. The device measures only the metacarpophalangeal joint of each finger directly and estimates the two outer joints from it; the authors started with 16 degrees of freedom and found 11 sufficient for skeletal reconstruction. With a 12-bit analog-to-digital converter the theoretical angular resolution is 0.09 degrees, but the paper puts the practical accuracy at about 0.5 degrees, and each feedback unit had a delay of 20-40 ms. The prototype weighed under 270 g and ran for 4 hours on an 800 mAh battery. The authors noted that this binary design could convey whether something was present but not how soft it was.

Later versions replaced the brake with what Dexta calls a "Direct Drive Method" using customized servo motors, which can produce variable force and simulate different stiffness levels, for example letting the user tell a rock from a rubber ball by squeezing it. Dexta's website says vibration actuators can also be built into the main body to simulate contact with different surfaces. Each motor's torque is limited to 5 kg.cm (0.5 N.m), and a Torque Output Monitoring function disables the motors under abnormal conditions.

Dexmo tracks 11 degrees of freedom per hand: three for the thumb (rotation, splitting and bending) and two each for the other four fingers (splitting and bending). It uses rotational sensors rather than inertial measurement units, which Dexta says keeps the readings unaffected by magnetic fields. It has no built-in positional tracking. A changeable mount accepts a Vive Tracker, an HTC Vive controller or an Oculus Touch controller, and Dexta says any system that supplies 6DoF data, including OptiTrack, can be used.

Development Kit 1 specifications

Specification (per hand)	DK1 value
Size	155 x 100 x 45 mm (L x W x D)
Weight	About 300 g
Battery	1800 mAh LiPo
Battery life	5 hours (specification table); the feature list claims up to 8 hours under normal use and over an hour under intensive use
Charge time	3 hours
Average power consumption	About 1000 mW
Motor torque (maximum)	5 kg.cm (0.5 N.m)
Wireless	2.4 GHz; optimal range 2 m, maximum 5 m
Latency (overall)	20-50 ms
Working temperature	-10 to 40 degrees C

Source: Dexta Robotics DK1 user manual, V3.0 (May 2019).

The DK1 box contains two Dexmo units (left and right), wireless dongles, a power adaptor, USB Type-C cables, a four-port USB 3.0 hub for plugging the dongles into an HTC Vive headset, connectors for Vive controllers, Vive Trackers and Oculus controllers, and finger straps. Dexta says it ships straps rather than gloves for hygiene and to fit different hand sizes when many people share a unit, and recommends a one-time hand calibration per user.

Software and features

Dexmo comes with an SDK, LibDexmo, and a Unity plugin. The DK1 manual says these work with Unity-supported devices such as the HoloLens, Oculus Rift CV1, HTC Vive and PlayStation VR, and the download links are provided only to buyers. Dexta's website also lists an Unreal Engine 4 plugin. In both engines developers assign a stiffness value to virtual objects through the SDK. The company's hand interaction physics engine, the Dexterity Engine, includes plug-and-play interaction modules; the 2019 Enterprise Edition release listed preset modules for pressing, twisting and grabbing.

Applications

In its 2019 announcement Dexta said Dexmo was used with car manufacturers to train new workers to place cables in cars. It listed electric car battery maintenance, assembly line training, flight simulation, power plant and nuclear station training, education, gaming, medical rehabilitation and humanoid robot teleoperation as other use cases. Its website shows example applications in these areas, including an escape-room game called Sanctum Escape.

The CHI 2016 study tested 20 participants in a Unity archery game played with a head-mounted display. Mean error rate fell from 61% without force feedback to 44% with it, a statistically significant difference; the authors cautioned that a novelty effect was likely.

Reception

The Red Dot jury wrote that the design "is strikingly reminiscent of a human skeleton." In 2016 Road to VR noted that the device could only push back against the fingers, and only within a limited range. Dexta also said that 40 volunteers had all found Dexmo more immersive than Vive controllers; Road to VR reported this without verifying it.

The VR blogger Skarredghost (The Ghost Howls) tried the gloves for about an hour in Beijing in 2019. The setup used servo force feedback, linear resonant actuators on the fingertips and palm, and a Vive Tracker for position. The reviewer said the force feedback reliably stopped his fingers from going through virtual objects and that variable stiffness, such as squeezing a rubber chicken, was convincing. The reviewer also called the force feedback "synthetic", reported a slight lag between seeing and feeling contact, and said the strap fitting was tight and setup often needed a helper. The review described the gloves as expensive, enterprise-oriented and still experimental.

See also

• Haptic gloves
• Force feedback
• Kinesthetic feedback
• Haptic rendering
• SenseGlove
• HaptX
• Exiii