Table of Contents

ENSsys: Keynote: Beyond the Next Paper: Building Foundations for the Next Decade of Batteryless Computing

Jacob Sorber, Clemson University

  • Batteryless harvesting has grown over time
  • Systems exists but are in research/prototype phase
  • Hard to compare different systems as most are botique
  • CICADA
    • NSF funded infrastructure project
    • Index of project artifacts
    • Org has people able to create docs, code, mfring
  • Challenge to maintain a project
  • Using ekho internally for almost a decade
  • Want to have hardware/firmware that people need
  • Open Questions
    • Resources/tools/device?
    • Reproducibility?
    • Standards?
    • Community engagement?
  • Comments
    • Going towards open source artifacts
    • Has interest in smfcs for harvesters
    • In papers, better explain the constraints and problems to solve
  • Reason for batteryless systems
    • Mobility
    • Application
    • Sustainability

Takeaways

  • Jacob is a good person to reach a an “org” for managing projects
  • CICADA good resource for state of the art/historical on batteryless systems

ENSsys: Harvesting and Computing

A Class AAA Solar Testbed for Reproducible Long-Term Characterization of Energy-Harvesting Systems

Lukas Schulthess, Andreas Rätz, Michele Magno, Philipp Mayer

  • Varying irradiance and spectral composition
  • Solar spectrum (AM1.5G)
  • Standards
    • IEC 60904-9: Solar spectrum
    • ASTM E927
  • Contribution: tune spectral tenability and illuminance range
  • Able to measure spectrum/light intensity to get real-world data
  • Has thermal control
  • https://github.com/ETH-PBL/Class-AAA-solar-testbed
  • approx 3500 USD
    • existing systems are 10000 USD
  • Can go down to low spectral intensities

Impact of Periodically Varying Illumination on Photovoltaic-Based Energy Harvesting Performance

Leander Hoermann, Lukas Springer, Veronika Putz

  • Using solar instead of difficult to use rotational environments
  • PWM LED neglected, not expected to impact output
  • “Low speed” rotation environments
  • Power output relative to angle
  • BQ25770 has fixed behavior of 16 seconds
  • Proposed multiple ways to fix

Raising Soil Microbial Fuel Cells into Robust Bio-Batteries

Simon Guterman, Pichaya Limprayoon, Diego Shipmon, John Mamish, Josiah Hester, Yaman Sangar

  • bactery startup with power output from smfcs
  • SMFC redox potential 0.8V
  • Cells did not recover after quick switching of a load
  • Conditioning the cells in necessary for power output
  • They have “memory” in terms of the resistance
  • Training load should be matched to the anticipated load

Exploring Biodegradable Non-volatile Memories for Intermittent Computing

Matteo Visotto, Andrea Maioli, Luca Mottola

  • Transient electronics, build a device that can degrade into the environment
  • Biodegradable resistor switching RAM (ReRAM)
  • Limitations
    • Number of switches (write endurance)
    • Retention time
  • Use ScEpTIC simulator
  • Create a model of different memories
  • Use “MementOS” and “Eleven” for MiBench2
  • Only 15 percent complete with success
  • Not taking into account any error margins in the material characteristics

Takeaway:

  • Active research being done on biodegradabiliy of specific sensor components

ENSsys: Communication

Energy-Adaptive and Delivery-Assured Batteryless LoRaWAN Image Sensing via Cross-Layer Co-Design

Samit Hasan, Yidi Wang, Daniel S. Truesdell, Victor Ariel Leal Sobral, Jonathan L. Goodall, Benton H Calhoun

  • Image sensing gives more context
  • For JPEG compression 55 precent failure rate at 2 percent PER
  • Combinations of policies for increase success rate
  • Cloud interface for scheduling based on solar availability
  • Choosing optimal number or retransmissions based on SNR
  • Tradeoff between throughput under ideal vs non-ideal cond.
  • Able to do CV on the images

Question:

  • How many devices can be supported on the network?

Energy–Latency Characterization of an Integrated Wake-Up Radio SoC

Patrick Pastorelli, Davide Brunelli and Matteo Nardello

  • Idle state dominates energy consumption for WSN nodes
  • Add a secondary low power receiver as wakeup signal
  • Multihop wakeup protocol
  • Tradeoffs with latency and power consumption
  • Wakeup radio has both TX/RX capabilities

Open World Radio Frequency Energy Harvesting-Based Eavesdropping Attack Model

Jiawen Chen, Tao Ni, Weitao Xu

  • Determine what app is being used based on RF energy harvesting profile
  • Using time domain and frquency domain classification
  • ML methods for determining features

ENSsys: Latest Advancements in Energy-Harvesting and Batteryless Systems

Robust Intermittent Computing in Space

Luca Mottola

  • Few large sats migrating to small sats
  • Space rated hardware
    • 2 to 3 gens behind
    • power hungry
    • ARGOS mission used Raspi 2
    • ie. off the shelf RAM fault rate is 2 orders of mag higher
  • Space good application for intermittent computation
  • NVM important, especially for GPS with wasted energy for acquisition
  • Robust is off-the-shelf NVM in LEO?
  • Tested
    • FRAM
    • STT-RAM
    • ReRAM
  • 14mm thick alumium to shield non-storage elements
  • EWSN25 paper on the radiation testing
  • Could only observe errors rather than original faults
  • STT-MRAM most robust tech
  • FRAM was terrible
    • 4 phases
      • 1st: many flips
      • 2nd: Decreased
      • 3rd: Decreased further
      • 4th: Lower and flatted
    • Blocks in FRAM typically 8 bits apart
  • FRAM/ReRAM have hard errors that don’t disappear
  • Conclusion
    • STT-MRAM: best size vs robustness, high current
    • ReRAM: bset when you need capacity at low power, but errors last longer
  • With ML workloads you are able to learn through errors
  • The x-ray/beryllium does not fully mimic spae
  • http://nanosat.nestlab.net
    • Dataset is public

Methods and tools for battery-less intermittent networks.

Marco Zimmerling

  • Evaluating energy harvesting systems is hard
    • Could be different energy harvesting conditions
  • Trying to control the energy availability over time
  • Shepherd Nova: extends original shepherd
  • MobiSys 2025
  • Target/observer combination deployed
  • Integrate nRF and MSP430 MCU
  • Can actually still by the RIOTE board mouser
  • Can have a community database of harvesting data
  • concept of “virtual source” that handles storage, harvesting, regulator
  • Collected a large range of data traces
  • Example use case: Battery-free neighbor discovery
  • https://niotee.nes-lab.org