Figure 1: Overview of picoRing mouse, enabling 30-500 uW-class ultra-low-power wireless ring mouse for ubiquitous finger input.The ring can potentially operate over a month on a single charge of a 27 mAh battery (https://youtu.be/7RazVNMx0Ms).

Smart rings for subtle, reliable finger input offer an attractive path for ubiquitous interaction with wearable computing platforms. However, compared to ordinary rings worn for cultural or fashion reasons, smart rings are much bulkier and less comfortable, largely due to the space required for a battery, which also limits the space available for sensors. This paper presents picoRing, a flexible sensing architecture that enables a variety of battery-free smart rings paired with a wristband. By inductively connecting a wristband-based sensitive reader coil with a ring-based fully-passive sensor coil, picoRing enables the wristband to stably detect the passive response from the ring via a weak inductive coupling. We demonstrate four different rings that support thumb-to-finger interactions like pressing, sliding, or scrolling. When users perform these interactions, the corresponding ring converts each input into a unique passive response through a network of passive switches. Combining the coil-based sensitive readout with the fully-passive ring design enables a tiny ring that weighs as little as 1.5 g and achieves a 13 cm stable readout despite finger bending, and proximity to metal.

Wearable devices for life-logging and healthcare have been studied, but the need for frequent charging imposes inconvenience for long-term use. Integrating textile-based wireless chargers (i.e., coil) into clothing enables sustainable wearable computing by charging the on-body devices in use. However, the electromagnetic field generated by conventional coil chargers strongly interferes with human body, and the high resistance of conductive threads leads to inefficient power delivery. This paper presents Meander Coil++, enabling safe, energy-efficient, and body-scale wireless power delivery. Meander Coil++ uses a wiring pattern that suppresses electromagnetic exposure to the human body without compromising power delivery performance and a liquid-metal-based low-loss conductive cord. With these advancements, Meander Coil++ transmits a few watts of power to on-body devices at 25% DC-to-DC efficiency while complying with international safety guidelines regarding electromagnetic exposure. We envision Meander Coil++ can maintain multiple devices on body for weeks beyond the confines of their small battery capacity.

We present PneuModule, a tangible interface platform that enables users to reconfigure physical controls on pressure-sensitive touch surfaces using pneumatically-actuated inflatable pin arrays. PneuModule consists of a main module and extension modules. The main module is tracked on the touch surface and forwards continuous inputs from attached multiple extension modules to the touch surface. Extension modules have distinct mechanisms for user input, which pneumatically actuates the inflatable pins at the bottom of the main module through internal air pipes. The main module accepts multi-dimensional inputs since each pin is individually inflated by the corresponding air chamber. Also, since the extension modules are swappable and identifiable owing to the marker design, users can quickly customize the interface layout. We contribute to design details of inflatable pins and diverse pneumatic input control design examples for PneuModule. We also showcase the feasibility of PneuModule through a series of evaluations and interactive prototypes.

Due to the spread of COVID-19, we are desired to avoid crowded places including public transportation. Kyushu University has the largest campus in Japan, called "Ito campus", and the population there is about 20,000 in which 23% of students and 46% of staff use a bus for reaching the campus. The lectures in the first half of 2020 have been conducted online, but we plan to resume face-to-face lectures gradually. At that time, we expect the bus stops and buses to be crowded, especially during rush hour. In this paper, we introduce a system, called Itocon, to visualize the human congestion of bus stops around the campus.

TelemetRing is a batteryless and wireless ring-shaped keyboard that supports command and text entry in daily lives by detecting finger typing on various surfaces. The proposed inductive telemetry approach eliminates bulky batteries or capacitors from the ring part. Each ring consists of a sensor coil (the ring part itself), 1-DoF piezoelectric accelerometer, and varactor diode; moreover, it has different resonant frequencies. Typing shocks slightly shift the resonant frequency, and these are detected by a wrist-mounted readout coil. 5-bit chord keyboard is realized by attaching five sensor rings on five fingers. Our evaluation shows that the prototype achieved the tiny (6 g, 3.5 cm^3) ring sensor and 89.7% of typing detection ratio.