Human Computer Integration Lab

User Authentication via Electrical Muscle Stimulation

Yuxin Chen, Zhuolin Yang, Ruben Abbou, Pedro Lopes, Ben Y. Zhao and Haitao Zheng, In Proc. CHI'21 (full paper)

We propose a novel modality for active biometric authentication: electrical muscle stimulation (EMS). To explore this, we engineered ElectricAuth, a wearable that stimulates the user’s forearm muscles with a sequence of electrical impulses (i.e., EMS challenge) and measures the user’s involuntary finger movements (i.e., response to the challenge). ElectricAuth leverages EMS’s intersubject variability, where the same electrical stimulation results in different movements in different users because everybody’s physiology is unique (e.g., differences in bone and muscular structure, skin resistance and composition, etc.). As such, ElectricAuth allows users to login without memorizing passwords or PINs. This is work was a colaboration led by Heather Zheng (who runs the SAND Lab) at UChicago.

Elevate: A Walkable Pin-Array for Large Shape-Changing Terrains

Seungwoo Je, Hyunseung Lim, Kongpyung Moon, Shan-Yuan Teng, Jas Brooks, Pedro Lopes, and Andrea Bianchi, In Proc. CHI'21 (full paper)

Existing shape-changing floors are limited by their tabletop scale or the coarse resolution of the terrains they can display due to the limited number of actuators and low vertical resolution. To tackle this, we engineered Elevate, a dynamic and walkable pin-array floor on which users can experience not only large variations in shapes but also the details of the underlying terrain. Our system achieves this by packing 1200 pins arranged on a 1.80 x 0.60m platform, in which each pin can be actuated to one of ten height levels (resolution: 15mm/level). This work was a collaboration and was led by Andrea Bianchi, who runs the MAKinteract group at KAIST.

HandMorph: a Passive Exoskeleton that Miniaturizes Grasp

Jun Nishida, Soichiro Matsuda, Hiroshi Matsui, Shan-Yuan Teng, Ziwei Liu, Kenji Suzuki, Pedro Lopes, In Proc. UIST’20 (full paper)
UIST best paper award

We engineered HandMorph, an exoskeleton that approximates the experience of having a smaller grasping range. It uses mechanical links to transmit motion from the wearer’s fingers to a smaller hand with five anatomically correct fingers. The result is that HandMorph miniaturizes a wearer’s grasping range while transmitting haptic feedback. Unlike other size-illusions based on virtual reality, HandMorph achieves this in the user’s real environment, preserving the user’s physical and social contexts. As such, our device can be integrated into the user’s workflow, e.g., to allow product designers to momentarily change their grasping range into that of a child while evaluating a toy prototype.

Trigeminal-based Temperature Illusions

Jas Brooks, Steven Nagels, Pedro Lopes, In Proc. CHI’20 (full paper) CHI best paper award (top 1%)

We explore a temperature illusion that uses low-powered electronics and enables the miniaturization of simple warm and cool sensations. Our illusion relies on the properties of certain scents, such as the coolness of mint or hotness of peppers. These odors trigger not only the olfactory bulb, but also the nose’s trigeminal nerve, which has receptors that respond to both temperature and chemicals. To exploit this, we engineered a wearable device that emits up to three custom-made “thermal” scents directly to the user’s nose. Breathing in these scents causes the user to feel warmer or cooler.

Wearable Microphone Jamming

Yuxin Chen*, Huiying Li∗, Shan-Yuan Teng∗, Steven Nagels, Pedro Lopes, Ben Y. Zhao and Heather Zheng, In Proc. CHI’20 (full paper)
* authors contributted equally CHI honorable mention for best paper award (top 5%)

We engineered a wearable microphone jammer that is capable of disabling microphones in its user’s surroundings, including hidden microphones. Our device is based on a recent exploit that leverages the fact that when exposed to ultrasonic noise, commodity microphones will leak the noise into the audible range. Our jammer is more efficient than stationary jammers. This is work was a colaboration led by Heather Zheng (who runs the SAND Lab) at UChicago.

Next Steps in Human Computer Integration

Floyd Mueller* ,Pedro Lopes*, Paul Strohmeier, Wendy Ju, Caitlyn Seim, Martin Weigel, Suranga Nanayakkara, Marianna Obrist, Zhuying Li, Joseph Delfa, Jun Nishida, Elizabeth Gerber, Dag Svanaes, Jonathan Grudin, Stefan Greuter, Kai Kunze, Thomas Erickson, Steven Greenspan, Masahiko Inami, Joe Marshall, Harald Reiterer, Katrin Wolf, Jochen Meyer, Thecla Schiphorst, Dakuo Wang, Pattie Maes. In Proc. CHI’20 (full paper) * authors contributted equally

Human-computer integration (HInt) is an emerging paradigm in which computational and human systems are closely interwoven; with rapid technological advancements and growing implications, it is critical to identify an agenda for future research in HInt.

Dream engineering: Simulating worlds through sensory stimulation

Michelle Carr, Adam Haar*, Judith Amores*, Pedro Lopes*, Guillermo Bernal, Tomás Vega, Oscar Rosello, Abhinandan Jain, Pattie Maes. In Proc. Consciousness and Cognition (Vol. 83, 2020) (journal paper) * authors contributted equally

We draw a parallel between recent VR haptic/sensory devices to further stimulate more senses for virtual interactions and the work of sleep/dream researchers, who are exploring how senses are intregrated and influence the sleeping mind. We survey recent developments in HCI technologies and analyze which might provide a useful hardware platform to manipulate dream content by sensory manipulation, i.e., to engineer dreams. This work was led by Michelle Carr (University of Rochester) and in collaboration with the Fluid Interfaces group (MIT Media Lab).

Aero-plane: a Handheld Force-Feedback Device that Renders Weight Motion Illusion

Seungwoo Je, Myung Jin Kim, Woojin Lee, Byungjoo Lee, Xing-Dong Yang, Pedro Lopes, Andrea Bianchi. In Proc. UIST’19 (full paper)

We engineered Aero-plane, a force-feedback handheld controller based on two miniature jet-propellers that can render shifting weights of up to 14 N within 0.3 seconds. Unlike other ungrounded haptic devices, our prototype realistically simulates weight changes over 2D surfaces. This work was a collaboration and was led by Andrea Bianchi, who runs the MAKinteract group at KAIST.

UIST'19 paper video

Action-dependent processing of touch in the human parietal operculum

Jakub Limanowski, Pedro Lopes, Janis Keck, Patrick Baudisch, Karl Friston, and Felix Blankenburg. In Cerebral Cortex (journal), to appear.

Tactile input generated by one’s own agency is generally attenuated. Conversely, externally caused tactile input is enhanced; e.g., during haptic exploration. We used functional magnetic resonance imaging (fMRI) to understand how the brain accomplishes this weighting. Our results suggest an agency-dependent somatosensory processing in the parietal operculum. Read more at our project's page.

Cerebral Cortex paper

Preemptive Action: Accelerating Human Reaction using Electrical Muscle Stimulation Without Compromising Agency

Shunichi Kasahara, Jun Nishida and Pedro Lopes. In Proc. CHI’19, Paper 643 (full paper) and demonstration at SIGGRAPH'19 eTech.

We found out that it is possible to optimize the timing of haptic systems to accelerate human reaction time without fully compromising the user' sense of agency. This work was done in cooperation with Shunichi Kasahara from Sony CSL. Read more at our project's page.

CHI'19 paper video SIGGRAPH'19 etech CHI'19 talk (slides) CHI talk video

Detecting Visuo-Haptic Mismatches in Virtual Reality using the Prediction Error Negativity of Event-Related Brain Potentials

Lukas Gehrke, Sezen Akman, Pedro Lopes, Albert Chen, ..., Klaus, Gramann. In Proc. CHI’19, Paper 427. (full paper)

We detect visuo-haptic mismatches in VR by analyzing the user's event-related potentials (ERP). In our EEG study, participants touched VR objects and received either no haptics, vibration, or vibration and EMS. We found that the negativity component (prediction error) was more pronounced in unrealistic VR situations, indicating visuo-haptic mismatches. Read more at our project's page.

CHI'19 paper CHI'19 talk (slides) CHI'19 talk video

Adding Force Feedback to Mixed Reality Experiences and Games using Electrical Muscle Stimulation

Pedro Lopes, Sijing You, Alexandra Ion, and Patrick Baudisch. In Proc. CHI’18. (full paper)

Summary: We present a mobile system that enhances mixed reality experiences, displayed on a Microsoft HoloLens, with force feedback by means of electrical muscle stimulation (EMS). The benefit of our approach is that it adds physical forces while keeping the users’ hands free to interact unencumbered—not only with virtual objects, but also with physical objects, such as props and appliances that are an integral part of both virtual and real worlds.

video CHI'18 paper code

Providing Haptics to Walls and Other Heavy Objects in Virtual Reality by Means of Electrical Muscle Stimulation

Pedro Lopes, Sijing You, Alexandra Ion, and Patrick Baudisch. In Proc. CHI’17 (full paper) and demonstration at SIGGRAPH'17 studios

We explored how to add haptics to walls and other heavy objects in virtual reality. Our contribution is that we prevent the user’s hands from penetrating virtual objects by means of electrical muscle stimulation (EMS). As the shown user lifts a virtual cube, our system lets the user feel the weight and resistance of the cube. The heavier the cube and the harder the user presses the cube, the stronger a counterforce the system generates.

video CHI'17 paper

Muscle-plotter: An Interactive System based on Electrical Muscle Stimulation that Produces Spatial Output

Pedro Lopes, Doga Yueksel, François Guimbretière, and Patrick Baudisch. In Proc. UIST’16 (full paper).

We explore how to create more expressive EMS-based systems. Muscle-plotter achieves this by persisting EMS output, allowing the system to build up a larger whole. More specifically, it spreads out the 1D signal produced by EMS over a 2D surface by steering the user’s wrist. Rather than repeatedly updating a single value, this renders many values into curves.

video UIST'16 paper code

Impacto: Simulating Physical Impact by Combining Tactile Stimulation with Electrical Muscle Stimulation

Pedro Lopes, Alexandra Ion, and Patrick Baudisch. In Proc. UIST’15 (full paper). UIST best demo nomination

We present impacto, a device designed to render the haptic sensation of hitting and being hit in virtual reality. The key idea that allows the small and light impacto device to simulate a strong hit is that it decomposes the stimulus: it renders the tactile aspect of being hit by tapping the skin using a solenoid; it adds impulse to the hit by thrusting the user’s arm backwards using electrical muscle stimulation. The device is self-contained, wireless, and small enough for wearable use.

video UIST'15 paper talk video

Affordance++: Allowing Objects to Communicate Dynamic Use

Pedro Lopes, Patrik Jonell, and Patrick Baudisch. In Proc. CHI’15 (full paper). CHI best paper award (top 1%)

We propose extending the affordance of objects by allowing them to communicate dynamic use, such as (1) motion (e.g., spray can shakes when touched), (2) multi-step processes (e.g., spray can sprays only after shaking), and (3) behaviors that change over time (e.g., empty spray can does not allow spraying anymore). Rather than enhancing objects directly, however, we implement this concept by enhancing the user with electrical muscle stimulation. We call this affordance++.

video CHI'15 paper talk video code

Proprioceptive Interaction

Pedro Lopes, Alexandra Ion, Willi Mueller, Daniel Hoffmann, Patrik Jonell, and Patrick Baudisch. In Proc. CHI’15 (full paper). CHI best talk award

We propose a new way of eyes-free interaction for wearables. It is based on the user’s proprioceptive sense, i.e., users feel the pose of their own body. We have implemented a wearable device, Pose-IO, that offers input and output based on proprioception. Users communicate with Pose-IO through the pose of their wrists. Users enter information by performing an input gesture by flexing their wrist, which the device senses using an accelerometer. Users receive output from Pose-IO by finding their wrist posed in an output gesture, which Pose-IO actuates using electrical muscle stimulation.

video CHI'15 paper talk video

Muscle-propelled force feedback: bringing force feedback to mobile devices

Pedro Lopes and Patrick Baudisch. In Proc. CHI’13 (short paper). IEEE World Haptics, People’s Choice Nomination for Best Demo

Force feedback devices resist miniaturization, because they require physical motors and mechanics. We propose mobile force feedback by eliminating motors and instead actuating the user’s muscles using electrical stimulation. Without the motors, we obtain substantially smaller and more energy-efficient devices. Our prototype fits on the back of a mobile phone. It actuates users’ forearm muscles via four electrodes, which causes users’ muscles to contract involuntarily, so that they tilt the device sideways. As users resist this motion using their other arm, they perceive force feedback.

video CHI'13 paper talk video

1. Introduction to Human-Computer Interaction (CMSC 20300; Fall quarter)

Synopsis: An introduction to the field of Human Computer Interaction (HCI), with a particular emphasis in understanding and designing user-facing software and hardware systems. This class covers the core concepts of HCI: affordance and mental models, input techniques (cursors, touch, text entry, voice, etc.), output techniques (visual menus and widgets, sound, haptics), conducting user studies, and so forth. It also includes a project in which students design, build and study a user-facing interactive system. See here for class website. (This class is required for our Undergraduate Specialization in HCI, see here for details.)

2. Inventing, Engineering and Understanding Interactive Devices (CMSC 23220; Spring quarter)

Synopsis: In this class we build I/O devices, typically wearable or haptic devices. These are user-facing hardware devices engineered to enable new ways to interact with computers. In order for you to be successful in building your own I/O device we will: (1) study and program 8 bit microntrollers, (2) explore different analog and digital sensors and actuators, (3) write control loops and filters, (4) explore stretchable and fabric based electronics, (5) learn how to approach invention, and (6) apply I/O devices to novel contexts such as Virtual Reality. See here for class website. (This class is part of our Undergraduate Specialization in HCI, see here for details.)

3. Engineering Interactive Electronics onto Printed Circuit Boards (CMSC 23230 and CMSC 33230; Spring quarter)

Synopsis: In this class we will engineer electronics onto Printed Circuit Boards (PCBs). We will focus on designing and laying out the circuit and PCB for our own custom-made I/O devices, such as wearable or haptic devices. In order for you to be successful in engineering a functional PCB we will: (1) review digital circuits and three microntrollers (ATMEGA, NRF, SAMD), (2) use KICAD to build circuit schematics; (3) learn how to wire analog/digital sensors or actuators to our microcontroller, including SPI and I2C protocols; (4) use KICAD to build PCB schematics; (5) actually manufacture our designs; (6) receive in our hands our PCBs from factory; (7) finally, learn how to debug our custom-made PCBs. See here for class website. (This class is part of our Undergraduate Specialization in HCI, see here for details.)