feat(ble): Add BLE RSSI room mapper example.

Author: MatteoCnda1

lib/ble/examples/BleRssiMapper/BleRssiMapper.ino

@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+// BleRssiMapper — record RSSI measurements at different positions in a room.
+//
+// Place 2-3 STeaMi boards running BleBeacon at known positions.
+// Move around the room with this board and send 'r' via Serial to record
+// the current RSSI of all visible beacons as a CSV row.
+// Send 's' to stop and print the full CSV.
+//
+// CSV format: point_id,beacon_name,rssi
+//
+// Open the serial monitor at 115200 baud.
+// Commands:
+//   r → record current RSSI for all visible beacons
+//   s → stop and print full CSV
+//   h → print help
+
+#include <Arduino.h>
+#include <STM32duinoBLE.h>
+
+// === Configuration ===
+static const char* BEACON_NAMES[] = {
+    "Beacon_M1",
+    "Beacon_M2",
+    "Beacon_M3",
+};
+static const int BEACON_COUNT = 3;
+static const int RSSI_SAMPLES = 5;
+static const int MAX_POINTS = 50;  // max measurement points
+static const int MAX_ROWS = MAX_POINTS * BEACON_COUNT;
+
+// === RSSI smoothing per beacon ===
+static int rssiHistory[3][RSSI_SAMPLES] = {{0}};
+static int rssiIndex[3] = {0};
+static int rssiCount[3] = {0};
+static int currentRssi[3];
+static bool beaconSeen[3] = {false};
+
+// === CSV storage (in RAM) ===
+struct CsvRow {
+    int pointId;
+    char beaconName[16];
+    int rssi;
+};
+static CsvRow csvData[MAX_ROWS];
+static int rowCount = 0;
+static int pointId = 0;
+static bool recording = true;
+
+// =============================================================================
+// === HELPERS =================================================================
+// =============================================================================
+
+int beaconIndex(const String& name) {
+    for (int i = 0; i < BEACON_COUNT; i++) {
+        if (name == BEACON_NAMES[i])
+            return i;
+    }
+    return -1;
+}
+
+void smoothRssi(int idx, int newRssi) {
+    rssiHistory[idx][rssiIndex[idx]] = newRssi;
+    rssiIndex[idx] = (rssiIndex[idx] + 1) % RSSI_SAMPLES;
+    if (rssiCount[idx] < RSSI_SAMPLES)
+        rssiCount[idx]++;
+    int sum = 0;
+    for (int i = 0; i < rssiCount[idx]; i++)
+        sum += rssiHistory[idx][i];
+    currentRssi[idx] = sum / rssiCount[idx];
+}
+
+void printHelp() {
+    Serial.println("=== BLE RSSI Room Mapper ===");
+    Serial.println("r → record current point");
+    Serial.println("s → stop and print CSV");
+    Serial.println("h → help");
+    Serial.println("============================");
+}
+
+void printCurrentScan() {
+    Serial.print("Point #");
+    Serial.print(pointId + 1);
+    Serial.print(" | Beacons: ");
+    for (int i = 0; i < BEACON_COUNT; i++) {
+        if (beaconSeen[i]) {
+            Serial.print(BEACON_NAMES[i]);
+            Serial.print("=");
+            Serial.print(currentRssi[i]);
+            Serial.print("dBm  ");
+        }
+    }
+    Serial.println();
+}
+
+void recordPoint() {
+    int seen = 0;
+    for (int i = 0; i < BEACON_COUNT; i++) {
+        if (beaconSeen[i])
+            seen++;
+    }
+
+    if (seen == 0) {
+        Serial.println("No beacon seen — move closer and retry.");
+        return;
+    }
+
+    pointId++;
+    Serial.print("Recording point #");
+    Serial.print(pointId);
+    Serial.print(" (");
+    Serial.print(seen);
+    Serial.println(" beacons)");
+
+    for (int i = 0; i < BEACON_COUNT; i++) {
+        if (beaconSeen[i] && rowCount < MAX_ROWS) {
+            csvData[rowCount].pointId = pointId;
+            strncpy(csvData[rowCount].beaconName, BEACON_NAMES[i], 15);
+            csvData[rowCount].rssi = currentRssi[i];
+            rowCount++;
+
+            Serial.print("  ");
+            Serial.print(BEACON_NAMES[i]);
+            Serial.print(", ");
+            Serial.println(currentRssi[i]);
+        }
+    }
+}
+
+void printCsv() {
+    Serial.println();
+    Serial.println("=== CSV OUTPUT — copy and save as rssi_map.csv ===");
+    Serial.println("point_id,beacon_name,rssi");
+    for (int i = 0; i < rowCount; i++) {
+        Serial.print(csvData[i].pointId);
+        Serial.print(",");
+        Serial.print(csvData[i].beaconName);
+        Serial.print(",");
+        Serial.println(csvData[i].rssi);
+    }
+    Serial.println("=== END OF CSV ===");
+    Serial.print("Total: ");
+    Serial.print(pointId);
+    Serial.print(" points, ");
+    Serial.print(rowCount);
+    Serial.println(" rows.");
+}
+
+// =============================================================================
+// === SETUP / LOOP ============================================================
+// =============================================================================
+
+void setup() {
+    Serial.begin(115200);
+    while (!Serial && millis() < 2000)
+        ;
+
+    if (!BLE.begin()) {
+        Serial.println("BLE init failed!");
+        while (true)
+            ;
+    }
+
+    BLE.scan(true);
+    printHelp();
+    Serial.println("Scanning for beacons...");
+}
+
+void loop() {
+    // Handle Serial commands
+    if (Serial.available()) {
+        char cmd = Serial.read();
+        if (cmd == 'r' && recording) {
+            recordPoint();
+        } else if (cmd == 's') {
+            recording = false;
+            BLE.stopScan();
+            printCsv();
+        } else if (cmd == 'h') {
+            printHelp();
+        } else if (cmd != '\n' && cmd != '\r') {
+            Serial.println("Unknown command. Send 'h' for help.");
+        }
+    }
+
+    // Update RSSI from scan results
+    if (recording) {
+        BLEDevice device = BLE.available();
+        if (device) {
+            int idx = beaconIndex(device.localName());
+            if (idx >= 0) {
+                smoothRssi(idx, device.rssi());
+                beaconSeen[idx] = true;
+            }
+        }
+
+        // Print current scan status every 2s
+        static unsigned long lastPrint = 0;
+        if (millis() - lastPrint > 2000) {
+            lastPrint = millis();
+            printCurrentScan();
+        }
+    }
+
+    BLE.poll();
+}