In this post, we explore a rough protocol for transferring large files over LoRa using ESP32 devices. The protocol involves sending metadata, file chunks, and an end-of-transfer message, with acknowledgment handling to ensure reliable transmission.

Explore how to send and receive structured messages using LoRa with ESP32 devices. Instead of sending simple strings, we use structs to include a MAC address for identification, extraction instructions, and a payload. By using an enum to declare message types and identifying the message type with the first byte (msgType), we eliminate the need to include message length in the transmission.

When developing with the ESP32 or Arduino, using the LoRa.onReceive function requires careful handling due to its operation within an interrupt context. Interrupt Service Routines (ISRs) in the ESP32 have stringent requirements and limitations. Performing complex or time-consuming tasks within an ISR can lead to various issues, including crashes and reboots.