#654 - Partial work for the LED/Speaker.

Framework is done. Just need to blink a few things and update protobufs.

src/plugins/ExternalNotificationPlugin.cpp

@@ -0,0 +1,108 @@
+#include "ExternalNotificationPlugin.h"
+#include "MeshService.h"
+#include "NodeDB.h"
+#include "RTC.h"
+#include "Router.h"
+#include "configuration.h"
+#include <Arduino.h>
+
+#include <assert.h>
+
+/*
+
+    bool ext_notification_plugin_enabled = 126;
+    uint32 ext_notification_plugin_output_ms = 127;
+    uint32 ext_notification_plugin_output = 128;
+    bool ext_notification_plugin_active = 129;
+    bool ext_notification_plugin_alert_message = 130;
+    bool ext_notification_plugin_alert_bell = 131;
+
+*/
+
+ExternalNotificationPlugin *externalNotificationPlugin;
+ExternalNotificationPluginRadio *externalNotificationPluginRadio;
+
+ExternalNotificationPlugin::ExternalNotificationPlugin() : concurrency::OSThread("ExternalNotificationPlugin") {}
+
+int32_t ExternalNotificationPlugin::runOnce()
+{
+#ifndef NO_ESP32
+
+    /*
+        Uncomment the preferences below if you want to use the plugin
+        without having to configure it from the PythonAPI or WebUI.
+    */
+
+    // radioConfig.preferences.externalnotificationplugin_enabled = 1;
+    // radioConfig.preferences.externalnotificationplugin_mode = 1;
+
+    if (0) {
+
+        if (firstTime) {
+
+            DEBUG_MSG("Initializing External Notification Plugin\n");
+
+            externalNotificationPluginRadio = new ExternalNotificationPluginRadio();
+
+            firstTime = 0;
+
+        } else {
+            /*
+
+                1) If GPIO is turned on ...
+                2) Check the timer. If the timer has elapsed more time than
+                   our set limit, turn the GPIO off.
+
+            */
+        }
+
+        return (25);
+    } else {
+        DEBUG_MSG("External Notification Plugin Disabled\n");
+
+        return (INT32_MAX);
+    }
+
+#endif
+}
+
+// --------
+
+MeshPacket *ExternalNotificationPluginRadio::allocReply()
+{
+
+    auto reply = allocDataPacket(); // Allocate a packet for sending
+
+    return reply;
+}
+
+bool ExternalNotificationPluginRadio::handleReceived(const MeshPacket &mp)
+{
+#ifndef NO_ESP32
+
+    if (0) {
+
+        auto &p = mp.decoded.data;
+
+        if (mp.from != nodeDB.getNodeNum()) {
+
+            /*
+                TODO: If ext_notification_plugin_alert_bell is true and we see a bell character, trigger an external notification.
+            */
+            // TODO: Check p.payload.bytes to see if it contains a bell character. If it does, trigger an external notifcation.
+
+            /*
+                TODO: If ext_notification_plugin_alert_message is true, trigger an external notification.
+            */
+            // TODO: On received packet, blink the LED.
+
+        }
+
+    } else {
+        DEBUG_MSG("External Notification Plugin Disabled\n");
+    }
+
+#endif
+
+    return true; // Let others look at this message also if they want
+}