系統以 LoRa ESP32-S3＋LoRa 無線模組為核心，預設 L4 Profile： SF9、125 kHz、Coding Rate 4/6。LoRa ESP32-S3 負責感測、資料封裝、 顯示與任務排程，LoRa 模組負責長距離短封包通訊；三種程式角色分別對應 受困者節點、搜救節點與 HQ 指揮鏈。

The system is built around LoRa ESP32-S3 + a LoRa radio module. Its default L4 profile uses SF9, 125 kHz bandwidth and coding rate 4/6. LoRa ESP32-S3 handles sensing, packet construction, display and task scheduling, while LoRa carries long-range short packets. Three program roles cover victim, rescue and HQ command-chain nodes.

三種韌體各自處理 LoRa、BLE 與本機警示，讓指揮命令、受困者狀態及緊急求救能在不同角色間傳遞。

Three firmware roles coordinate LoRa, BLE and local alerts to carry commands, victim status and emergency calls.

主迴圈採高速輪詢，以 millis() 獨立排程各項任務。Victim 一般模式每 15 秒回報， SOS 時縮短為 3 秒；Rescue 一般模式每 3 秒回報，並提供 Mountain、Power Save、 Ultra Save、Quake 與 Silent 模式；HQ 每 5 秒發送 HQPING。

The high-speed polling loop schedules independent tasks with millis(). Victim reports every 15 seconds, or every 3 seconds in SOS mode. Rescue reports every 3 seconds in Normal mode and also provides Mountain, Power Save, Ultra Save, Quake and Silent modes. HQ sends HQPING every 5 seconds.

Victim 會在 30 秒無互動後關閉 OLED，完成發送後讓無線電進入休眠，並依 RSSI 在 14／18／22 dBm 間動態調整功率；發送前再自動喚醒。

Victim turns off its OLED after 30 seconds of inactivity, sleeps the radio after transmission, wakes it before the next send, and adjusts output power among 14, 18 and 22 dBm according to RSSI.

發送前先執行 LoRa 頻道活動偵測，並搭配 Binary Exponential Backoff： BE 2–4、5 ms Slot、最多 3 次嘗試。系統使用 18 個搜尋頻道分流，另以 433 MHz 承載 HQ 指揮鏈、913 MHz 承載隊伍命令。

Before transmission, LoRa channel activity detection is combined with binary exponential backoff: BE 2–4, 5 ms slots and up to three attempts. Eighteen search channels distribute traffic, while 433 MHz carries the HQ chain and 913 MHz carries team commands.

Rescue 保存最近 10 個封包 ID、HQ 保存最近 20 個，避免重複套用；SOS 與 MAYDAY 採週期重播，緊急封包同時使用搜尋頻率與 913 MHz 雙頻送出，提升抵達率。

Rescue retains the latest 10 packet IDs and HQ retains 20 for deduplication. SOS and MAYDAY use periodic rebroadcasting, while emergency packets are sent on both the search frequency and 913 MHz to improve delivery.

線路資料使用 UTF-8 字串，以 | 分隔；共用 Header 依序為 pktId、pairCode、senderID、type、payload。接收端以 pktId 去重， pairCode 則用於區分不同隊伍。

On-air data uses UTF-8 strings separated by |. The shared header is pktId, pairCode, senderID, type and payload. Receivers deduplicate by pktId, while pairCode separates teams.

// Victim SOS · 典型 27–32 bytes
pktId|pair|sender|SOS|B{bat}|BPM{hr}

// Rescue Team · 典型 30–40 bytes
pktId|pair|sender|TEAM|B{bat}|V{count}|D{dept}

// Mayday · 約 80–150 bytes（含 GPS）
pktId|pair|sender|MAYDAY|B{bat}|N{name}|T{title}|LAT{lat}|LON{lon}|ACC{accuracy}

預設 L4 Profile 下，30-byte 封包空中時間約 0.25 秒、100-byte 約 0.65 秒、 200-byte 約 1.19 秒；系統依 255-byte payload 上限管理可變長度內容。

Under the default L4 profile, estimated time-on-air is approximately 0.25 seconds for 30 bytes, 0.65 seconds for 100 bytes and 1.19 seconds for 200 bytes. Variable-length content is managed within the 255-byte payload limit.