Revision 0:490b5d248e91, committed 2020-11-22

Comitter:

nsejim

Date:

Sun Nov 22 12:16:19 2020 +0000

Commit message:

Code example of sending LoRa message to Things Network gateway and be relayed to the associated ThingSpeak channel

Changed in this revision

diff -r 000000000000 -r 490b5d248e91 main.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun Nov 22 12:16:19 2020 +0000
@@ -0,0 +1,133 @@
+#include "mbed.h" // Include the library of Mbed
+#include "LoRaWANInterface.h"
+#include "SX1276_LoRaRadio.h"
+
+
+/*
+Send LoRa message to a the group project Thingspeak channel
+https://thingspeak.com/channels/1234574/feed.json
+ */
+
+// The port we're sending and receiving on
+#define MBED_CONF_LORA_APP_PORT     1
+
+InterruptIn send_data_button(p6);
+
+// Device credentials, register device as OTAA in The Things Network and copy credentials here
+static uint8_t DEV_EUI[] = { 0x18, 0x11, 0x20, 0x20, 0x18, 0x11, 0x20, 0x20 };
+static uint8_t APP_EUI[] = { 0x70, 0xB3, 0xD5, 0x7E, 0xD0, 0x03, 0x84, 0x15 };
+static uint8_t APP_KEY[] = { 0x76, 0x8B, 0xD9, 0x68, 0xA9, 0x4C, 0xC0, 0xF6, 0x52, 0x20, 0x48, 0x7C, 0x00, 0xE6, 0x0D, 0x3C };
+
+
+// Peripherals (LoRa radio, temperature sensor and button)
+SX1276_LoRaRadio radio(D11, D12, D13, D10, A0, D2, D3, D4, D5, D8, D9, NC, NC, NC, NC, A4, NC, NC);
+
+// EventQueue is required to dispatch events around
+static EventQueue ev_queue;
+// Constructing Mbed LoRaWANInterface and passing it down the radio object.
+static LoRaWANInterface lorawan(radio);
+// Application specific callbacks
+static lorawan_app_callbacks_t callbacks;
+// LoRaWAN stack event handler
+static void lora_event_handler(lorawan_event_t event);
+
+// Send a message over LoRaWAN
+static void send_message(char *device, long int start, long int end, int topic) {
+    uint8_t tx_buffer[50] = { 0 };
+    // Sending strings over LoRaWAN is not recommended
+    sprintf((char*) tx_buffer, "{\"device\":\"%s\",\"start\":%ld,\"end\":%ld,\"topic\":%d}", device, start, end, topic);
+    int packet_len = strlen((char*) tx_buffer);
+    printf("Sending %d bytes: \"%s\"\n", packet_len, tx_buffer);
+    int16_t retcode = lorawan.send(MBED_CONF_LORA_APP_PORT, tx_buffer, packet_len, MSG_UNCONFIRMED_FLAG);
+    // for some reason send() returns -1... I cannot find out why, the stack returns the right number. I feel that this is some weird Emscripten quirk
+    if (retcode < 0) {
+        retcode == LORAWAN_STATUS_WOULD_BLOCK ? printf("send - duty cycle violation\n")
+                : printf("send() - Error code %d\n", retcode);
+        return;
+    }
+    printf("%d bytes scheduled for transmission\n", retcode);
+}
+
+int initialize_lora() {
+    if (DEV_EUI[0] == 0x0 && DEV_EUI[1] == 0x0 && DEV_EUI[2] == 0x0 && DEV_EUI[3] == 0x0 && DEV_EUI[4] == 0x0 && DEV_EUI[5] == 0x0 && DEV_EUI[6] == 0x0 && DEV_EUI[7] == 0x0) {
+        printf("Set your LoRaWAN credentials first!\n");
+        return -1;
+    }
+    if (lorawan.initialize(&ev_queue) != LORAWAN_STATUS_OK) {
+        printf("LoRa initialization failed!\n");
+        return -1;
+    }
+    // prepare application callbacks
+    callbacks.events = mbed::callback(lora_event_handler);
+    lorawan.add_app_callbacks(&callbacks);
+    // Disable adaptive data rating
+    if (lorawan.disable_adaptive_datarate() != LORAWAN_STATUS_OK) {
+        printf("disable_adaptive_datarate failed!\n");
+        return -1;
+    }
+    lorawan.set_datarate(5); // SF7BW125
+    lorawan_connect_t connect_params;
+    connect_params.connect_type = LORAWAN_CONNECTION_OTAA;
+    connect_params.connection_u.otaa.dev_eui = DEV_EUI;
+    connect_params.connection_u.otaa.app_eui = APP_EUI;
+    connect_params.connection_u.otaa.app_key = APP_KEY;
+    connect_params.connection_u.otaa.nb_trials = 3;
+
+    lorawan_status_t retcode = lorawan.connect(connect_params);
+
+    if (retcode == LORAWAN_STATUS_OK ||
+        retcode == LORAWAN_STATUS_CONNECT_IN_PROGRESS) {
+    } else {
+        printf("Connection error, code = %d\n", retcode);
+        return -1;
+    }
+
+    printf("LoRa Connection - In Progress ...\r\n");
+    // make your event queue dispatching events forever
+    ev_queue.dispatch_forever();
+    return 0;
+}
+
+void send_data_button_isr() {
+
+     char device[] = "MyDevice";
+     int topic = 3; // topic identifier
+     long int start = 1606037871;  // start reading
+     long int end = 1606038051; // end reading
+
+     send_message(device, start, end, topic);
+}
+
+int main() {
+    send_data_button.rise(ev_queue.event(&send_data_button_isr)); // Registering an ISR for button click
+    initialize_lora();
+}
+
+// Event handler
+static void lora_event_handler(lorawan_event_t event) {
+    switch (event) {
+        case CONNECTED:
+            printf("LoRA Connection - Successful\n");
+            break;
+        case DISCONNECTED:
+            ev_queue.break_dispatch();
+            printf("LoRa Disconnected Successfully\n");
+            break;
+        case TX_DONE:
+            printf("Message Sent to Network Server\n");
+            break;
+        case TX_TIMEOUT:
+        case TX_ERROR:
+        case TX_CRYPTO_ERROR:
+        case TX_SCHEDULING_ERROR:
+            printf("Transmission Error - EventCode = %d\n", event);
+            break;
+        case JOIN_FAILURE:
+            printf("OTAA Failed - Check Keys\n");
+            break;
+        default:
+            MBED_ASSERT("Unknown Event");
+    }
+}
+
+