diff --git a/firmware/fieldtest_beacon/platformio.ini b/firmware/fieldtest_beacon/platformio.ini
new file mode 100644
index 0000000..5453277
--- /dev/null
+++ b/firmware/fieldtest_beacon/platformio.ini
@@ -0,0 +1,22 @@
+; platformio.ini
+; 20260212 ChatGPT
+; $Id$
+; $HeadURL$
+
+[platformio]
+default_envs = tbeam_supreme
+
+[env:tbeam_supreme]
+platform = espressif32
+framework = arduino
+board = esp32-s3-devkitc-1          ; <-- change to your exact board if needed
+monitor_speed = 115200
+
+; Pull in microReticulum from your repo tree
+build_flags =
+  -I ../../external/microReticulum/src
+  -D FIELDTEST_BEACON=1
+
+lib_deps =
+  ; SD stack usually comes with Arduino core
+  ; Add your LoRa radio library here (RadioLib, SX126x-Arduino, etc.)
diff --git a/firmware/fieldtest_beacon/src/main.cpp b/firmware/fieldtest_beacon/src/main.cpp
new file mode 100644
index 0000000..ede2bf8
--- /dev/null
+++ b/firmware/fieldtest_beacon/src/main.cpp
@@ -0,0 +1,116 @@
+// firmware/fieldtest_beacon/src/main.cpp
+// 20260212 ChatGPT
+// $Id$
+// $HeadURL$
+
+#include <Arduino.h>
+#include <SPI.h>
+#include <SD.h>
+
+// Include microReticulum headers from your external tree
+#include "Identity.h"
+#include "Reticulum.h"
+#include "Destination.h"
+#include "Transport.h"
+
+// ---------- User-tunable ----------
+static const uint32_t BEACON_INTERVAL_MS = 15000;
+static const char* PATH_IDENTITY_BIN = "/provisioning/identity.bin";
+static const char* PATH_LABEL_TXT    = "/provisioning/label.txt";
+static const char* LOG_PATH          = "/logs/fieldtest.log";
+
+// ---------- Globals ----------
+static uint32_t g_iter = 0;
+static uint32_t g_next_tx = 0;
+static File g_log;
+
+// TODO: replace with your board’s SD CS pin if not default
+static const int SD_CS_PIN = 10;
+
+// Simple line logger (append-only)
+static void log_line(const String& line) {
+  if (!g_log) return;
+  g_log.println(line);
+  g_log.flush();
+}
+
+// Read whole file into a buffer
+static bool read_file(const char* path, std::vector<uint8_t>& out) {
+  File f = SD.open(path, FILE_READ);
+  if (!f) return false;
+  size_t n = f.size();
+  out.resize(n);
+  if (n > 0) f.read(out.data(), n);
+  f.close();
+  return true;
+}
+
+static String read_text_file(const char* path) {
+  File f = SD.open(path, FILE_READ);
+  if (!f) return String("");
+  String s = f.readString();
+  f.close();
+  s.trim();
+  return s;
+}
+
+void setup() {
+  Serial.begin(115200);
+  delay(250);
+
+  // ---- SD init ----
+  if (!SD.begin(SD_CS_PIN)) {
+    Serial.println("SD init failed");
+    return;
+  }
+
+  g_log = SD.open(LOG_PATH, FILE_APPEND);
+  if (!g_log) {
+    Serial.println("Failed to open log file");
+    return;
+  }
+
+  const String label = read_text_file(PATH_LABEL_TXT);
+  log_line("BOOT\tlabel=" + label);
+
+  std::vector<uint8_t> id_bytes;
+  if (!read_file(PATH_IDENTITY_BIN, id_bytes)) {
+    log_line(String("ERROR\tmissing_identity\tpath=") + PATH_IDENTITY_BIN);
+    return;
+  }
+  log_line(String("IDENTITY_OK\tbytes=") + id_bytes.size());
+
+  // ---- Load Identity into microReticulum ----
+  // TODO: adjust to the actual API in your microReticulum version
+  // Example intent:
+  //   Identity ident = Identity::fromBytes(id_bytes.data(), id_bytes.size());
+  //   Reticulum rns;
+  //   rns.setIdentity(ident);
+  //   rns.begin(...);
+  //
+  // Also: initialize your LoRa Interface and attach it to Reticulum here.
+
+  log_line("RNS_INIT_OK");
+
+  g_next_tx = millis() + 3000; // wait a moment before first TX
+}
+
+void loop() {
+  // TODO: run microReticulum polling / tick function, and radio interface polling
+
+  const uint32_t now = millis();
+  if ((int32_t)(now - g_next_tx) >= 0) {
+    g_next_tx = now + BEACON_INTERVAL_MS;
+
+    // Build payload: timestamp + iterator (GPS later)
+    const uint32_t epoch_guess = (uint32_t) (time(nullptr)); // placeholder; GPS later
+    const String payload = String("t=") + epoch_guess + " i=" + g_iter++;
+
+    // TODO: send to peer(s) (Destination derived from peers list)
+    // bool ok = destination.send(payload_bytes, len);
+
+    log_line(String("TX\t") + payload);
+  }
+
+  delay(5);
+}