An ultra-low energy human activity recognition accelerator for wearable health applications

Ganapati Bhat, Yigit Tuncel, Sizhe An, Hyung Gyu Lee, Umit Y. Ogras

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Human activity recognition (HAR) has recently received significant attention due to its wide range of applications in health and activity monitoring. The nature of these applications requires mobile or wearable devices with limited battery capacity. User surveys show that charging requirement is one of the leading reasons for abandoning these devices. Hence, practical solutions must offer ultra-low power capabilities that enable operation on harvested energy. To address this need, we present the first fully integrated custom hardware accelerator (HAR engine) that consumes 22.4 μJ per operation using a commercial 65 nm technology. We present a complete solution that integrates all steps of HAR, i.e., reading the raw sensor data, generating features, and activity classification using a deep neural network (DNN). It achieves 95% accuracy in recognizing 8 common human activities while providing three orders of magnitude higher energy efficiency compared to existing solutions.

Original languageEnglish (US)
Article numbera49
JournalACM Transactions on Embedded Computing Systems
Issue number5s
StatePublished - Oct 2019


  • Flexible hybrid electronics
  • Hardware accelerator
  • Health monitoring
  • Human activity recognition
  • Low-power design
  • Wearable electronics

ASJC Scopus subject areas

  • Software
  • Hardware and Architecture


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