Ye-Sheng Kuo

Hijacking power and bandwidth from the mobile phone's audio interface

The mobile phone is the most pervasive personal communications and computing platform ever created and yet, among its various analog interfaces, only one is open, standardized, and widely accessible: the headset port. In this demo, we augmente the mobile phone with a range of phone-powered peripherals. We show that the mobile phone headset port can be used to efficiently power external peripherals and communicate with them, enabling many new phone-centric applications. But, why use the headset port at all? One reason is that it is an open, simple, and ubiquitous interface with documented electrical and mechanical specifications. Perhaps even more important, the headset interface is backward-and forward-compatible with most mobile phones in use today.

A millimeter-scale wireless imaging system with continuous motion detection and energy harvesting

We present a 2×4×4mm3 imaging system complete with optics, wireless communication, battery, power management, solar harvesting, processor and memory. The system features a 160×160 resolution CMOS image sensor with 304nW continuous in-pixel motion detection mode. System components are fabricated in five different IC layers and die-stacked for minimal form factor. Photovoltaic (PV) cells face the opposite direction of the imager for optimal illumination and generate 456nW at 10klux to enable energy autonomous system operation.

IoT design space challenges: Circuits and systems

The Internet of Things (IoT) is a rapidly emerging application space, poised to become the largest electronics market for the semiconductor industry. IoT devices are focused on sensing and actuating of our physical environment and have a nearly unlimited breadth of uses. In this paper, we explore the IoT application space and then identify two common challenges that exist across this space: ultra-low power operation and system design using modular, composable components. We survey recent low power techniques and discuss a low power bus that enables modular design. Finally, we conclude with three example ultra-low power, millimeter-scale IoT systems.

Putting the software radio on a low-calorie diet

Modern software-defined radios are large, expensive, and power-hungry devices and this, we argue, hampers their more widespread deployment and use, particularly in low-power, size-constrained application settings like mobile phones and sensor networks. To rectify this problem, we propose to put the software-defined radio on a diet by redesigning it around just two core chips -- an integrated RF transceiver and a Flash-based, mixed-signal FPGA. Modern transceivers integrate almost all RF front-end functions while emerging FPGAs integrate nearly all of required signal conditioning and processing functions. And, unlike conventional FPGAs, Flash-based FPGAs offer sleep mode power draws measured in the microamps and startup times measured in the microseconds, both of which are critical for low-power operation. If our platform architecture vision is realized, it will be possible to hold a software-defined radio in the palm of ones hand, build it for

MBus: A 17.5 pJ/bit/chip portable interconnect bus for millimeter-scale sensor systems with 8 nW standby power

100, and power it for days using the energy in a typical mobile phone battery. This will make software radios deployable in high densities and broadly accessible for research and education.

A case for custom silicon in enabling low-cost information technology for developing regions

We propose an ultra-low power interconnect bus for millimeter-scale wireless sensor nodes. Using only 4 IO pads, the bus minimizes the required chip real estate, enabling ultrasmall form factors in modular sensor node designs. Low power is achieved using a “clockless” design of member nodes while aggressive power gating allows an ultra-low power standby mode with only 53 gates powered on. An integrated wakeup scheme is compatible with PMUs that have a special low power standby mode. The MBus is fully synthesizable and uses robust timing. Implemented in a 3 module system in 180nm technology, Mbus achieves 8nW of standby power and 17.5 pJ/bit/chip.

Demo: Michigan's IoT Toolkit

Information and communications technology has the potential for deep social impact in developing regions but todays typical ICT devices -- laptops, mobile phones, and similar devices -- are often still too expensive for many scenarios. In this paper, we argue that custom integrated circuits can enable a new tier of low-cost information access devices with a price point that will make them widely accessible. And, with control over the silicon, these systems can economically address many other challenges. To evaluate our claim, we focus on a deceptively simple problem -- low-cost information access for illiterate populations through audio recordings -- and show how custom silicon allows us to reduce cost, lower power, leverage conventional infrastructure in unconventional ways, and optimize the interface for usability. In particular, we show how a rural audio computer can be designed around just three chips, use an inexpensive capacitive touch interface, employ inductive communications for peer-to-peer data transfer, and employ content download over GSM voice and FM broadcast as two wide area options. The resulting design point -- enabled by aggressive silicon integration -- affords a device that can be built for

Demo abstract: A compact, inexpensive, and battery-powered software-defined radio platform

7.77, a third of the cost achievable using commercial off-the-shelf components.

MBus: an ultra-low power interconnect bus for next generation nanopower systems

Building connected, pervasive, human-facing, and responsive applications that incorporate local sensors, smartphone interactions, device actuation, and cloud-based learning--the promised features of the Internet of Things (IoT)---requires a complete suite of tools spanning both hardware and software. We present a set of these pieces, including a gateway, four hardware building blocks, multiple sensor platforms, an indoor localization system, and software for connecting users and devices. Each piece plays an integral role towards enabling applications, from facilitating rapid development of wireless smart devices to composing data streams and services from a diverse set of components. By providing layered interoperable systems, our toolkit offers cohesive support for moving beyond single-device, cloud-centric applications---typical in todays IoT landscape--and towards richer applications that incorporate multiple data streams, human interaction, cloud processing, location awareness, multiple communication protocols, historical data, access control, and on-demand user interfaces. To show how the pieces in the toolkit cooperate, we demonstrate a location-based access control application where a users smartphone can control a rooms lighting, but only from within the room. Further, data streams from the phone and nearby sensors are used to provide a constant lighting service which attempts to maintain a user-set brightness under variable external lighting conditions.

From Energy Audits to Monitoring Megawatt Loads: A Flexible and Deployable Power Metering System

ABSTRACT We present μSDR, a compact, inexpensive, and battery-powered software-defined radio (SDR) platform built on a single-chip, flash-based FPGA fabric and ARM Cortex-M3 processor, enabling lower power and tighter hardware/soft-ware integration than prior commodity SDR platforms. Our architecture, unlike prior designs, is well-suited to hand-held or battery-operated systems and also supports cleaner partitioning since hardware can be easily mapped into the software addresses space, and vice versa. Building on this flexi-bility, we show how highly time-critical MAC protocols can be implemented on this platform and deployed using just AAA batteries.