ORCA: Offload Rethinking by Cloud Assistance for Efficient Environmental Sound Recognition on LPWANs

A usable LoRa driver for intermittent communication on MSP430FR5994 for ultra-low-power edge-cloud collaborative learning.

This paper is accepted by [SenSys'25] Offload Rethinking by Cloud Assistance for Efficient Environmental Sound Recognition on LPWANs

File Structure

.
├── driverlib/MSP430FR5xx_6xx         // MSP430 Drivers
├── targetConfigs                     // MSP430 Configs
├── README.md
├── lora.h                            // RFM95 macros from RadioHead
├── fsk.h                             // RFM95 macros from RadioHead
├── reg.h                             // RFM95 registers macros from RadioHead
├── main.c                            // Entry point, RFM95 function calls

Prerequisites

MSP430FR5994 Launchpad, RFM95 (SX1276) LoRa breakout, and jumper wires

Wiring

                   MSP430FR5994
                 -----------------
            /|\ |             P1.0|-> Comms LED
             |  |                 |
             ---|RST          P1.4|-> RFM95 Reset (GPIO)
                |             P1.5|-> RFM95 Interrupt (IX)
                |             P5.0|-> Data Out (UCB1SIMO)
                |                 |
       Button ->|P5.5         P5.1|<- Data In (UCB1SOMI)
   Button LED <-|P1.1             |
                |             P5.2|-> Serial Clock Out (UCB1CLK)
                |                 |
                |             P5.3|-> RFM95 Chip Select (GPIO)

Get Started

Intialize RFM95

rf_init_lora();

Configure Tx and Rx

lora_set_txconfig();
lora_set_rxconfig();

Tx

lora_send(SEND_BUFFER, SEND_SIZE);
__bis_SR_register(LPM3_bits | GIE);       // Wait for TxDone interrupt

Rx

lora_recv();                              // Set up Rx
start_timer(RX_WINDOW_SIZE);              // Set up a timer for Rx window

Acknowledgements

This repo is developed and adapted from MSP430_LoRaWAN and RadioHead.

The machine learning library is referred to Capuchin, a highly customizable ultra-low-power machine learning model generator for MSP430.

Cite me

@misc{zhang2025offloadrethinkingcloudassistance,
      title={Offload Rethinking by Cloud Assistance for Efficient Environmental Sound Recognition on LPWANs}, 
      author={Le Zhang and Quanling Zhao and Run Wang and Shirley Bian and Onat Gungor and Flavio Ponzina and Tajana Rosing},
      year={2025},
      eprint={2502.15285},
      archivePrefix={arXiv},
      primaryClass={cs.SD},
      url={https://arxiv.org/abs/2502.15285}, 
}