Sensor Systems Laboratory

Inventing new technology for sensing, robotics, wireless power, and medical devices

Joshua R. Smith, Ph. D.
Director, Amazon Science Hub
Milton and Delia Zeutschel Professor
Allen School of Computer Science and Engineering
Department of Electrical and Computer Engineering
University of Washington

Recent Publications

Magnetic field coupling with lunar soil simulants, Shanti M. Garman, Melissa C. Roth, Vincent G. Roux, Joshua R. Smith, Nature Scientific Reports 13 (9713), June 15, 2023, doi: 10.1038/s41598-023-36527-0  [pdf]

Communication by means of modulated Johnson noise, Zerina Kapetanvic, Miguel Morales, Joshua R. Smith, Proceedings of the National Academy of Science, Vol. 119, No. 49, e2201337119, November 1, 2022 [Arxiv]

A ±0.5-mV-Minimum-Input DC-DC Converter With Stepwise Adiabatic Gate-Drive and Efficient Timing Control for Thermoelectric Energy Harvesting, Eric J. Carlson and Joshua R, Smith, in IEEE Transactions on Circuits and Systems I: Regular Papers, 2022, doi: 10.1109/TCSI.2022.3219402 [Techrxiv]

Acoustic Balance: Weighing in Ultrasonic Non-Contact Manipulators, Jared Nakahara, Joshua R. Smith, IEEE Robotics and Automation Letters 7 (4), 9145-9150, 2022 [pdf]

Analysis and Design of a Multi-hop Resonant Wireless Power Transfer System: Optimal Intermediate Coil Size and Location, Kedi Yan, Gregory E. Moore, Joshua R. Smith, Wireless Power Week (WPW), 454-459, 2022

Smart breast clip: A wireless implant for continuous molecular sensing of breast masses, Alicia Y. Wei, Gregory Moore, Kedi Yan, Brody Mahoney, Joahua R. Smith, Thomas D. O'Sullivan, Label-free Biomedical Imaging and Sensing (LBIS) 2022, PC1197215, 2022

Motivating Physical Activity via Competitive Human-Robot Interaction, Boling Yang, Golnaz Habibi, Patrick Lancaster, Byron Boots, Joshua R. Smith Smith, Conference on Robot Learning, 839-849, 2022

Stackelberg MADDPG: Learning Emergent Behaviors via Information Asymmetry in Competitive Games, B Yang, L Zheng, LJ Ratliff, B Boots, JR Smith, AAAI Reinforcement Learning in Games Workshop, 2022

Lessons for robotics from the control architecture of the octopus, Dominic M. Sivitilli, Joshua R. Smith, David H. Gire, Frontiers in Robotics and AI, 131, 2022

Adaptive Wireless Power Transfer and Backscatter Communication for Perpetual Operation of Wireless Brain-Computer Interfaces, Gregory E. Moore, James D. Rosenthal, Joshua R. Smith, Matthew S. Reynolds, Proceedings of the IEEE, December 10, 2021 

Proximity Perception in Human-centered Robotics: A Survey on Sensing Systems and Applications, Stefan Escaida Navarro, Stephan Mühlbacher-Karrer, Hosam Alagi, Hubert Zangl, Keisuke Koyama, Björn Hein, Christian Duriez, Joshua R. Smith, IEEE Transactions on Robotics, November 1, 2021

Brain-Computer-Spinal Interface Restores Upper Limb Function After Spinal Cord Injury, Soshi Samejima, Abed Khorasani, Vaishnavi Ranganathan1, Jared Nakahara, Nicholas M Tolley, Adrien Boissenin, Vahid Shalchyan, Mohammad Reza Daliri, Joshua R Smith, Chet T Moritz, IEEE Transactions on Neural Systems and Rehabilitation Engineering, Vol 29, pp 1233-1242, June 17, 2021

WHISPER: Wireless Home Identification and Sensing Platform for Energy Reduction, Margarite Jacoby, Sin Yong Tan, Mohamad Katanbaf, Ali Saffari, Homagni Saha, Zerina Kapetanovic, Jasmine Garland, Anthony Florita, Gregor Henze, Soumik Sarkar, Joshua Smith, Journal of Sensor and Actuator Networks, 2021. [pdf]

MultiScatter: Multistatic Backscatter Networking for Battery-Free Sensors, Mohamad Katanbaf, Ali Saffari, Joshua R Smith, SenSys 2021. [pdf]

Battery-Free Camera Occupancy Detection System, Ali Saffari, Sin Yong Tan, Mohamad Katanbaf, Homagni Saha, Joshua R Smith, Soumik Sarkar, EMDL 2021

Simplifying Backscatter Deployment: Full-Duplex LoRa Backscatter,  Mohamad Katanbaf, Anthoney Weinanad, Vamsi Talla, NSDI 2021

Receiver Selectivity Limits on Bistatic Backscatter Range, Mohamad Katanbaf, Ali saffari, Joshua R. Smith, 2020 IEEE International Conference on RFID, 2020

Contact-less Manipulation of Millimeter-scale Objects via Ultrasonic Levitation, Jared Nakahara, Boling Yang, Joshua R. Smith, 8th IEEE RAS/EMBS International Conference for Biomedical Robotics and Biomechatronics (BioRob), 2020

Classifying WLAN Packets from the RF Envelope: Towards More Efficient Wireless Netowrk Performance, Zerina Kapetanovic*, Gregory Moore*, Shanti Garman, Joshua. R. Smith, ACM EMDL 2020  (*Primary Co-authors)

Relacks: Reliable Backscatter Communication in indoor environmens, Mohamad Katanbaf, Vivek Jain, Joshua R. Smith, Proceedings of the ACM on Interactive, Mobile, Wearable, and Ubiquitous Technologies, 2020 [pdf]

Glaze: Overalying Occupied Spectrum with Downlink IoT Transmissions, Zerina Kapetanovic, Ali Saffari, Ranveer Chandra, Joshua. R. Smith, Proceedings of the ACM on Interactive, Mobile, Wearable, and Ubiquitous Technologies, 2020 [Video]

Advances and Open Problems in Backscatter Networking, Vamsi Talla, Joshua Smith, Shyamnath Gollakota, GetMobile: Mobile Computing and Communications Vol 24 Issue 4, pp 32-38, December 2020

Improved Proximity, Contact, and Force Sensing via Optimization of Elastomer-Air Interface Geometry, Patrick E. Lancaster, Joshua R. Smith, Siddhartha S. Srinivasa, IEEE International Conference on Robotics and Automation, May 2019.


Battery_Free Video Streaming Camera System, Ali Saffari, Mehrdad Hessar, Saman Naderiparizi, Joshua R. Smith, IEEE International Conference on RFID (RFID), April, 2019.


NeuralCLIP: A Modular FPGA-Based Neural Interface for Closed-Loop Operation, Vaishnavi Ranganathan, Jared Nakahara, Soshi Samejima, Nicholas Tolley, Abed Khorasani, Chet T. Moritz, Joshua R. Smith, 9th International IEEE EMBS Conference on Neural Engineering, March 20, 2019.


RF Bandaid: A Fully-Analog and Passive Wireless Interface for Wearable Sensors, Vaishnavi Ranganathan, Sidhant Gupta, Jonathan Lester, Joshua R. Smith, Desney Tan, Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies, June 2018. ***Distinguished Paper award winner*** 


Wireless Quantization Index Modulation: Enabling Communication Through Existing Signals, Zerina Kapetanovic, Vamsi Talla, Aaron Parks , Jing Qian, Joshua Smith, IEEE RFID, 2018/4/10. Best Paper Nominee


RF-powered, Backscatter-based Cameras, Saman Naderiparizi, Zerina Kapetanovic, Joshua R. Smith, IEEE 11th European Conference on Antennas and Propagation (EUCAP), pp. 346-349, 2017.

LoRa Backscatter: Enabling the Vision of Ubiquitous Connectivity, Vamsi Talla,2 Mehrdad Hessar, Bryce Kellogg, Ali Najafi, Joshua R. Smith, Shyamnath Gollakota, Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies (IMWUT), September 15, 2017. ***Distinguished Paper award winner*** 


Battery-Free Cellphone, Vamsi Talla,2 Bryce Kellogg, Shyamnath Gollakota, Joshua R. Smith, Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies (IMWUT), September 15, 2017.

Fast Downstream to Many (Computational) RFIDs, Henko Aantjes, Amjad Y Majid, Przemyslaw Pawelczak, Jethro Tan, Aaron Parks, Joshua R Smith, Proc. IEEE INFOCOM 2017, June 14, 2017.


Pre-touch Sensing for Sequential Manipulation, Boling Yang, Patrick Lancaster, Joshua R. Smith, Proceedings of ICRA 2017, May 2017.


Finding Common Ground: A Survey of Capacitive Sensing in Human-Computer Interaction, Tobias Grosse-Puppendahl, Christian Holz, Gabe Cohn, Raphael Wimmer, Oskar Bechtold, Steve Hodges, Matthew S Reynolds, Joshua R Smith, Proceedings of the 2017 ACM SIGCHI Conference (CHI 2017), May 6, 2017.


FM Backscatter: Enabling Connected Cities and Smart Fabrics, Anran Wang, Vikram Iyer, Vamsi Talla, Joshua R. Smith, Shyamnath Gollakota, 14th USENIX Symposium on Networked Systems Design and Implementation (NSDI 17), March 27, 2017.


Passive Wi-Fi: Bringing Low Power to Wi-Fi Transmissions, Bryce Kellogg, Vamsi Talla, Shyamnath Gollakota, Joshua R. Smith, Usenix Symposium on Networked Systems Design and Implementation (NSDI), 2016. ***Best Paper***


2D and 3D Millimeter-Wave Synthetic Aperture Radar Imaging on a PR2 Platform, Claire M Watts, Patrick Lancaster, Andreas Pedross-Engel, Joshua R Smith, Matthew S Reynolds, IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2016), October, 2016.


Inter-Technology Backscatter: Towards Internet Connectivity for Implanted Devices, Vikram Iyer, Vamsi Talla, Bryce Kellogg, Shyamnath Gollakota, Joshua R Smith, Proceedings of the 2016 ACM SIGCOMM Conference (SIGCOMM 2016), August 2016. ***Best Paper***


Battery-Free Connected Machine Vision with WISPCam, Saman Naderiparizi, Zerina Kapetanovic, Joshua R. Smith, GetMobile Magazine, 2016.


WISPCam: An RF-Powered Smart Camera for Machine Vision Applications, Saman Naderiparizi, Zerina Kapetanovic, Joshua R. Smith, ASPLOS HLPC Workshop, April 2016.


Design and Analysis of Rectifying and Regulating Rectifier with PWM and PFM Modes, Vamsi Talla, Joshua R. Smith, , May 2016.


A High-Voltage Compliant Neural Stimulator With HF Wireless Power and UHF Backscatter Communication, Vaishnavi Ranganathan, Brody Mahoney, Eric Pepin, Michael Sunshine, Chet T. Moritz, Jacques C. Rudell, Joshua R. Smith, IEEE WPTC, 2016.


Analysis of a Near Field Communication Wireless Power System, Yi Zhao, Brody Mahoney, Joshua R. Smith, IEEE WPTC, 2016.


Dual Band Wireless Power and Bi-Directional Data Link for Implanted Devices in 65 nm CMOS, Vamsi Talla, Vaishnavi Ranganathan, Brody Mahoney, Joshua R. Smith, , May 2016.


A high-voltage compliant neural stimulator with HF wireless power and UHF backscatter communication, Vaishnavi Ranganathan, Brody Mahoney, Eric Pepin, Michael D Sunshine, Chet T Moritz, Jacques C Rudell, Joshua R Smith, 2016 IEEE Wireless Power Transfer Conference (WPTC 2016), May 2016.


BLISP: Enhancing backscatter radio with active radio for computational RFIDs, Ivar in't Veen, Qingzhi Liu, Przemyslaw Pawelczak, Aaron Parks, Joshua R Smith, 2016 IEEE International Conference on RFID (IEEE RFID 2016), May 2016.


uMonitor: In-situ Energy Monitoring with Microwatt power consumption, Saman Naderiparizi, Aaron N. Parks, Farshid Salemi, Joshua R. Smith, IEEE RFID, May 2016.


Wisent: Robust downstream communication and storage for computational RFIDs, Jethro Tan, Przemysław Pawełczak, Aaron Parks, Joshua R Smith, IEEE INFOCOMM, The 35th Annual IEEE International Conference on Computer Communications, April 2016.


Large Area Wireless Power via a Planar Array of Coupled Resonators, Xingyi Shi, Joshua R. Smith, IEEE IWAT, Feb 2016.


Transmissive Optical Pretouch Sensing for Robotic Grasping, Di Guo, Patrick Lancaster, Liang-Ting Jiang, Fuchun Sun, Joshua R. Smith, Intelligent Robots and Systems (IROS), 2015 IEEE/RSJ International Conference on, Hamburg, pp. 5891-5897, 2015.

Powering the Next Billion Devices with Wi-Fi, V Talla,1 B Kellogg, B Ransford,2 S Naderiparizi,1 S Gollakota, JR Smith, ACM CoNext, Heidelberg, Germany, December 1-4, 2015. Nominated for Best Paper Award

Self-Localizing Battery-Free Cameras, Saman Naderiparizi, Yi Zhao, James Youngquist, Alanson P. Sample, Joshua R. Smith, Proceedings of the 2015 ACM International Joint Conference on Pervasive and Ubiquitous Computing. ACM, September 2015.


NFC-WISP: an open source software defined near field RFID sensing platform, Yi Zhao, Joshua R. Smith, Alanson Sample, Ubicomp, 2015.


WISPCam: A Battery-Free RFID Camera, Saman Naderiparizi, Aaron N. Parks, Zerina Kapetanovic, Benjamin Ransford, Joshua R. Smith, IEEE RFID, April 15-17 2015.


Physical human interactive guidance: Identifying grasping principles from human-planned grasps, R Balasubramanian, L Xu, PD Brook, JR Smith, Y Matsuoka, The Human Hand as an Inspiration for Robot Hand Development, pp 477-500, Springer, 2014.

The Emergence of RF-Powered Computing, S. Gollakota, M. Reynolds, J.R. Smith, D. Wetherall, IEEE Computer, Vol. 47, No. 1, pp. 32-39, Jan 2014.

Enabling Seamless Wireless Power Delivery in Dynamic Environments, Alanson P. Sample, Benjamin H. Waters, Scott Wisdom, Joshua R. Smith, (Invited) Proceedings of the IEEE, Vol 101, Issue 6, pp. 1343-1358, June 2013.

Evaluation of Wireless Resonant Power Transfer Systems with Human Electromagnetic Exposure Limits, Andreas Christ, Mark G. Douglas, John Roman, Emily B. Cooper, Alanson P. Sample, Benjamin H. Waters, Joshua R. Smith, Niels Kuster, IEEE Transactions on Electromagnetic Compatibility, Vol. 55, Issue 2, pp.  265-275. April 2013.

Physical Human Interactive Guidance: Identifying Grasping Principles From Human-Planned Grasps, Ravi Balasubramanian, Ling Xu, Peter Brook, Joshua R. Smith, Yoky Matsuoka, IEEE Transactions on Robotics (T-RO), Vol. 28 No. 4, pp. 899-910, Aug. 2012.

Powering a Ventricular Assist Device (VAD) with the Free-range Resonant Electrical Energy Delivery (FREE-D) System, B. H. Waters, A. P. Sample, P. Bonde, J.R. Smith. (Invited) Proceedings of the IEEE, vol. 100, No. 1, pp. 138-149, January 2012.

Analysis, Experimental Results, and Range Adaptation of Magnetically Coupled Resonators for Wireless Power Transfer, Alanson P. Sample, David T. Meyer, Joshua R. Smith, IEEE Transactions on Industrial Electronics, Vol. 58, No. 2, pp 544-554, Feb 2011.

RFID: From Supply Chains to Sensor Nets, S. Roy, V. Jandhyala, J.R. Smith, D.J. Wetherall, B.P. Otis, R. Chakraborty, M. Buettner, D.J. Yeager, Y.-C. Ko, A.P. Sample1, Proceedings of the IEEE, vol.98, no.9, pp.1583-1592, Sept. 2010. 

NeuralWISP: A Wirelessly Powered Neural Interface with 1-m Range, Daniel J. Yeager, Jeremy Holleman, Richa Prasad, Joshua R. Smith, and Brian Otis, IEEE Transactions on Biomedical Circuits and Systems, Volume 3, Issue 6, pp. 379-387, Oct 2009.

Design of an RFID-Based Battery-Free Programmable Sensing Platform.  A.P. Sample, D.J. Yeager, P.S. Powledge, A.V. Mamishev, J.R. Smith.  IEEE Transactions on Instrumentation and Measurement, Vol. 57, No. 11, pp. 2608-2615, Nov. 2008

Energy scavenging for inductively coupled passive RFID systems.  B. Jiang4, J. R. Smith, M. Philipose, S. Roy, K. Sundara-Rajan4, and A. Mamishev.  IEEE Transactions on Instrumentation and Measurement, Vol. 56, No. 1, pp. 118-125, February 2007

RFID-Based Techniques for Human Activity Detection.  Joshua R. Smith, Kenneth P. Fishkin, Bing Jiang4,  Alexander Mamishev, Matthai Philipose, Adam Rea, Sumit Roy, Kishore Sundara-Rajan4. Communications of the ACM, v48, no. 9, pp. 39-44, Sep 2005.

Battery-Free Wireless Identification and Sensing.  Matthai Philipose, Joshua R. Smith, Bing Jiang4, Kishore Sundara-Rajan4, Alexander Mamishev, Sumit Roy. IEEE Pervasive Computing, Vol. 4, No. 1, pp. 37-45, January-March 2005.

Electric Field Sensing for Graphical Interfaces. Joshua R. Smith, Tom White, Christopher Dodge, David Allport, Joseph Paradiso, and Neil Gershenfeld.  Computer Graphics and Applications, Vol. 18, No. 3, pp 54-61, 1998.

Field Mice: Extracting Hand Geometry From Electric Field Measurements. Joshua R. Smith. IBM Systems Journal, Vol. 35, No. 3&4, pp 587-608, 1996.