From cb1cc5e64c0db865de76de2e34f1bcb5f90a2dfd Mon Sep 17 00:00:00 2001
From: "Matthias P. Braendli" <matthias.braendli@mpb.li>
Date: Wed, 10 May 2023 17:59:11 +0200
Subject: Transmit locator over LoRa

---
 README.md    |   2 +-
 src/main.ino | 115 ++++++++++++++++++++++++++++++++++++++++-------------------
 2 files changed, 79 insertions(+), 38 deletions(-)

diff --git a/README.md b/README.md
index 71a3e6d..cc43f96 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 NUCLEO-H743ZI APRS-LoRa Tracker
 ===============================
 
-Connect u-blox NEO-M8N (or other u-blox receiver) to USART-B (RX PD5 and TX PD6) and RFM96 to SPI.
+Connect u-blox NEO-M8N (or other u-blox receiver) to USART-B (RX PD5 and TX PD6) and RFM96 to SPI A and 
 
 See src/main.ino for definitions.
 
diff --git a/src/main.ino b/src/main.ino
index fe4ef95..4bcca3e 100644
--- a/src/main.ino
+++ b/src/main.ino
@@ -4,15 +4,17 @@
 #include <SparkFun_u-blox_GNSS_Arduino_Library.h>
 
 // SX1278 has the following connections:
-// NSS pin:   10
-// DIO0 pin:  2
-// RESET pin: 9
-// DIO1 pin:  3
-RFM96 radio = new Module(10, 2, 9, 3);
-
+// NSS pin:   PD14 (Arduino 10)
+// DIO0 pin:  PF3 (Arduino 8)
+// RESET pin: PF15 (Arduino 9)
+RFM96 radio = new Module(10, 8, 9);
 HardwareSerial SerialGNSS(PD6, PD5);
 SFE_UBLOX_GNSS gnss;
+
 long lastGnssPoll = 0;
+long lastPositionReport = 0;
+constexpr size_t POSITION_REPORT_LEN = 32;
+char positionReport[POSITION_REPORT_LEN+1];
 
 static char letterize(int x) {
     return (char) x + 65;
@@ -66,9 +68,8 @@ void setup() {
     byte versionLow = gnss.getProtocolVersionLow();
     Serial.println(versionLow);
 
-#if 0
     Serial.print(F("[RFM] Init "));
-    int state = radio.begin();
+    int state = radio.begin(433.900);
     if (state == RADIOLIB_ERR_NONE) {
         Serial.println(F("success!"));
     } else {
@@ -77,8 +78,38 @@ void setup() {
         while (true);
     }
 
+    if (radio.setBandwidth(125.0) == RADIOLIB_ERR_INVALID_BANDWIDTH) {
+        Serial.println(F("Selected bandwidth is invalid for this module!"));
+        while (true);
+    }
+
+    if (radio.setSpreadingFactor(12) == RADIOLIB_ERR_INVALID_SPREADING_FACTOR) {
+        Serial.println(F("Selected spreading factor is invalid for this module!"));
+        while (true);
+    }
+
+    if (radio.setCodingRate(5) == RADIOLIB_ERR_INVALID_CODING_RATE) {
+        Serial.println(F("Selected coding rate is invalid for this module!"));
+        while (true);
+    }
+
+    // NOTE: value 0x34 is reserved for LoRaWAN networks and should not be used
+    if (radio.setSyncWord(0x14) != RADIOLIB_ERR_NONE) {
+        Serial.println(F("Unable to set sync word!"));
+        while (true);
+    }
+
+    if (radio.setOutputPower(16) == RADIOLIB_ERR_INVALID_OUTPUT_POWER) {
+        Serial.println(F("Selected output power is invalid for this module!"));
+        while (true);
+    }
+
+    if (radio.setPreambleLength(8) == RADIOLIB_ERR_INVALID_PREAMBLE_LENGTH) {
+        Serial.println(F("Selected preamble length is invalid for this module!"));
+        while (true);
+    }
+
     // radio.setRfSwitchPins(4, 5);
-#endif
 }
 
 void loop()
@@ -95,7 +126,7 @@ void loop()
         Serial.print(F(" Long: "));
         Serial.print(longitude);
 
-        char* locator = get_mh((double)latitude/1e7, (double)longitude/1e7, 6);
+        char *locator = get_mh((double)latitude/1e7, (double)longitude/1e7, 10);
         Serial.print(F(" Loc: "));
         Serial.print(locator);
 
@@ -109,45 +140,55 @@ void loop()
         Serial.print(speed);
         Serial.print(F(" (mm/s)"));
 
-        long heading = gnss.getHeading();
-        Serial.print(F(" Heading: "));
-        Serial.print(heading);
-        Serial.print(F(" (degrees * 10^-5)"));
+        /*
+           long heading = gnss.getHeading();
+           Serial.print(F(" Heading: "));
+           Serial.print(heading);
+           Serial.print(F(" (degrees * 10^-5)"));
+         */
 
         byte SIV = gnss.getSIV();
         Serial.print(F(" SIV: "));
         Serial.print(SIV);
 
+        Serial.print(F(" TX in: "));
+        constexpr long TX_INTERVAL = 15000;
+        Serial.print(TX_INTERVAL - (now - lastPositionReport));
+
         Serial.println();
-    }
-}
 
-void loop2()
-{
-    digitalWrite(LED_BUILTIN, HIGH);
-    delay(1000);
+        if (now - lastPositionReport > TX_INTERVAL) {
+            lastPositionReport = now;
 
-    Serial.print(F("[RFM] Transmitting packet ... "));
+            digitalWrite(LED_BUILTIN, HIGH);
 
-    int state = radio.transmit("Hello World!");
+            ssize_t len = snprintf(positionReport, POSITION_REPORT_LEN, "HB9EGM %s", locator);
 
-    if (state == RADIOLIB_ERR_NONE) {
-        Serial.println(F(" success!"));
-        Serial.print(F("[RFM] Datarate:\t"));
-        Serial.print(radio.getDataRate());
-        Serial.println(F(" bps"));
+            Serial.print(F("TX: "));
+            Serial.print(positionReport);
 
-    } else if (state == RADIOLIB_ERR_PACKET_TOO_LONG) {
-        Serial.println(F("too long!"));
+            int state = radio.transmit(positionReport, len);
 
-    } else if (state == RADIOLIB_ERR_TX_TIMEOUT) {
-        Serial.println(F("timeout!"));
+            if (state == RADIOLIB_ERR_NONE) {
+                Serial.print(F(" RFM OK Datarate: "));
+                Serial.print(radio.getDataRate());
+                Serial.println(F(" bps"));
 
-    } else {
-        Serial.print(F("failed, code "));
-        Serial.println(state);
-    }
+            }
+            else if (state == RADIOLIB_ERR_PACKET_TOO_LONG) {
+                Serial.println(F(" too long!"));
 
-    digitalWrite(LED_BUILTIN, LOW);
-    delay(1000);
+            }
+            else if (state == RADIOLIB_ERR_TX_TIMEOUT) {
+                Serial.println(F(" timeout!"));
+
+            }
+            else {
+                Serial.print(F(" failed, code "));
+                Serial.println(state);
+            }
+
+            digitalWrite(LED_BUILTIN, LOW);
+        }
+    }
 }
-- 
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