BLE Support (#87)

* Add support for BLE

Currently the cadence is set to 100ms and the minimum required by
FlySkyHigh is 200ms

* [Feature] Debugging:  Memory Usage Task

Adds a task for debugging memory utilization, once per second to print to console on debug releases.

* [Memory] Reduce the number of waypoints

Greatly reduces the amount of RAM needed.

[Memory] Memory optimization.  Make the graphics Consts.  Get them out of DRAM

* [BLE] Finished first run.

- Moved BLE to use the NimBLE package.  Apparently it's lighter on resources
- This demo also had a callback class that could let us re-advertise on a disconnect
- Plugged it into the preferences.

---------

Co-authored-by: Ankit Goyal <goyalankit40@gmail.com>

platformio.ini

@@ -48,6 +48,9 @@ lib_deps =
 	; RadioLib for LoRa / Fanet
 	jgromes/RadioLib@^7.1.2
 
+	; For reduced memory BLE Server Support
+	h2zero/NimBLE-Arduino@^2.2.3
+
 [env:release]
 extends = env
 build_unflags = -D ARDUINO_USB_MODE
@@ -65,6 +68,7 @@ build_flags =
 	${env.build_flags}
 	-D DEBUG_WIFI  # Enables WiFi on boot, enables webserver, does not disable Wifi after setup
 	-D DISABLE_MASS_STORAGE  # Disables mass storage on SD card mount
+	-D MEMORY_PROFILING  # Enables memory profiling troubleshooting features
 	-D ARDUINO_USB_MODE=1
 	-D ARDUINO_USB_CDC_ON_BOOT=1  # Required for USB Serial on boot (for debugging)  
 

src/vario/PageMenuSystem.cpp

@@ -4,6 +4,7 @@
 
 #include "PageMenuAbout.h"
 #include "PageMenuSystemWifi.h"
+#include "ble.h"
 #include "buttons.h"
 #include "display.h"
 #include "displayFields.h"
@@ -196,8 +197,14 @@ void SystemMenuPage::setting_change(Button dir, ButtonState state, uint8_t count
       redraw = true;
       break;
     case cursor_system_bluetooth:
-      if (state == RELEASED) {
+      if (state != RELEASED) break;
+      BLUETOOTH_ON = !BLUETOOTH_ON;
+      if (BLUETOOTH_ON) {
+        BLE::get().setup();
+      } else {
+        BLE::get().end();
       }
+      settings_save();
       break;
     case cursor_system_reset:
       if (state == RELEASED || state == NO_STATE) {

src/vario/ble.cpp

@@ -0,0 +1,115 @@
+#include "ble.h"
+#include <Arduino.h>
+
+#include <NimBLEDevice.h>
+#include "baro.h"
+#include "etl/string.h"
+#include "fanet_radio.h"
+
+// These new unique UUIDs came from
+// https://www.uuidgenerator.net/
+
+#define LEAF_SERVICE_UUID "92b38cf3-4bd0-428c-aca4-ae6c3a586835"
+// LK8EX1 Telemetry notification
+#define LEAF_LK8EX1_UUID "583918da-fb9b-4645-bbaf-2db3b1a9c1b3"
+
+class ServerCallbacks : public NimBLEServerCallbacks {
+  // Not sure we need this.  Taken from the demo
+  void onConnect(NimBLEServer* pServer, NimBLEConnInfo& connInfo) override {
+    /**
+     *  We can use the connection handle here to ask for different connection parameters.
+     *  Args: connection handle, min connection interval, max connection interval
+     *  latency, supervision timeout.
+     *  Units; Min/Max Intervals: 1.25 millisecond increments.
+     *  Latency: number of intervals allowed to skip.
+     *  Timeout: 10 millisecond increments.
+     */
+    pServer->updateConnParams(connInfo.getConnHandle(), 24, 48, 0, 180);
+  }
+
+  // This one seems import to re-advertise
+  void onDisconnect(NimBLEServer* pServer, NimBLEConnInfo& connInfo, int reason) override {
+    // Re-advertise after a disconnect
+    NimBLEDevice::startAdvertising();
+  }
+
+} serverCallbacks;
+
+BLE& BLE::get() {
+  static BLE instance;
+  return instance;
+}
+
+void BLE::setup() {
+  // Initialize the BLE with the unique device name
+  etl::string<13> name = "Leaf: ";
+  name += FanetRadio::getAddress().c_str();
+  NimBLEDevice::init(name.c_str());
+
+  // Create a server using the callback class to re-advertise on a disconnect
+  pServer = NimBLEDevice::createServer();
+  pServer->setCallbacks(&serverCallbacks);
+
+  // Create the characteristic and start advertising climb rate information
+  NimBLEService* pService = pServer->createService(LEAF_SERVICE_UUID);
+  pCharacteristic = pService->createCharacteristic(LEAF_LK8EX1_UUID,
+                                                   NIMBLE_PROPERTY::READ | NIMBLE_PROPERTY::NOTIFY);
+  pService->start();
+
+  /** Create an advertising instance and add the services to the advertised data */
+  pAdvertising = NimBLEDevice::getAdvertising();
+  pAdvertising->setName(name.c_str());
+  pAdvertising->addServiceUUID(pService->getUUID());
+  /**
+   *  If your device is battery powered you may consider setting scan response
+   *  to false as it will extend battery life at the expense of less data sent.
+   */
+  pAdvertising->enableScanResponse(true);
+  pAdvertising->start();
+}
+
+uint8_t checksum(std::string_view string) {
+  uint8_t result = 0;
+  for (int i = 1; i < string.find('*'); i++) {
+    result ^= string[i];
+  }
+  return result;
+}
+
+void BLE::loop() {
+  // Short circuit if not running or no connected clients
+  if (!pServer || !pServer->getConnectedCount()) return;
+
+  char stringified[50];
+  snprintf(stringified,
+           sizeof(stringified),
+           // See https://raw.githubusercontent.com/LK8000/LK8000/master/Docs/LK8EX1.txt
+           ("$LK8EX1,"  // Type of update
+            "%u,"       // raw pressure in hPascal
+            "99999,"  // altitude in meters, relative to QNH 1013.25. 99999 if not available/needed
+            "%d,"     // Climb rate in cm/s.  Can be 99999 if not available
+            "99,"     // Temperature in C.  If not available, send 99
+            "999,"  // Battery voltage OR percentage.  If percentage, add 1000 (if 1014 is 14%). 999
+                    // if unavailable
+            "*"     // Checksum to follow
+            ),
+           baro.pressureFiltered,
+           baro.climbRateFiltered);
+  // Add checksum and delimeter with newline
+  snprintf(stringified + strlen(stringified), sizeof(stringified), "%02X\n", checksum(stringified));
+  pCharacteristic->setValue((const uint8_t*)stringified, sizeof(stringified));
+  pCharacteristic->notify();
+
+  // TODO:  Need lines for GPS and Fanet updates
+}
+
+void BLE::end() {
+  // Delete any objects created and deinit manually.. Seems to crash setting this to true
+  NimBLEDevice::deinit(false);
+
+  // Reset null pointers.
+  pServer = nullptr;
+  pService = nullptr;
+  pCharacteristic = nullptr;
+  pAdvertising = nullptr;
+}

src/vario/ble.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <NimBLEDevice.h>
+
+class BLE {
+ public:
+  static BLE& get();
+
+  void setup();
+  void loop();
+  void end();
+
+ private:
+  BLE() : pServer(nullptr), pService(nullptr), pCharacteristic(nullptr), pAdvertising(nullptr) {}
+
+  NimBLEServer* pServer;
+  NimBLEService* pService;
+  NimBLECharacteristic* pCharacteristic;
+  NimBLEAdvertising* pAdvertising;
+};
+;