Informing the design of a LoRa™-based digital bracelet for the timely assistance of indigents

We conducted a qualitative study to get a preliminary understanding of indigents needs. The results helped us identify system requirements that led to the design of the HELPi system, a digital bracelet to enable local agencies to provide support to indigents who used roam the city. The paper aims to present the studies conducted to inform the design of our technological approach to addressing challenges related to acceptance, coverage of users, and battery lifespan. We built a prototype using LoRa™, which is a Low Power Wide Area Network (LPWAN) technology that offers several features that make it suitable for our application domain; e.g., it enables Machine-to-Machine (M2M) communications. Thus, we have taken advantage of this feature and propose a communication protocol to allow a dynamic coverage of users. We conducted assessments to determine users’ perception about its usefulness, and to measure the performance of the LoRa’s signal propagation and the battery energy consumption for the deployment of the HELPi system. According to our results, the proposed communication protocol should work with a LoRa™ Gateway in the outside setting condition and with an SNR threshold higher than − 2 dB to guarantee the successful reception of messages transmitted.