Initial public release of WII5 Buoy firmware

Firmware for an autonomous wave-measurement buoy (ATmega2560-based
WII5 v2 board). Reads wave motion from a Sparton AHRS-M1/M2 IMU,
samples GPS and battery state, and reports back over Iridium SBD
satellite telemetry. Originally developed 2012-2024.

This is the first public release. Code, documentation, and field-tested
operating modes (Capture, Sleep, Position, ManualTest, SelfTest,
LowBattery) are licensed under Apache 2.0 — see LICENSE and NOTICE.

See README.md for an overview and build instructions, CONTRIBUTING.md
for how to contribute, and DEPLOYMENTS.md for the field-deployment log.

WII5Battery.h

@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright (c) 2012-2024 Scott Penrose <scottp@dd.com.au> and WII5 Buoy contributors
+//
+// This file is part of WII5 Buoy firmware.
+// See LICENSE for full terms.
+
+/**
+ * @file WII5Battery.h
+ * @brief Battery monitor: voltage sampling, running average, and threshold logic.
+ */
+
+#ifndef WII5Battery_h
+#define WII5Battery_h
+
+#include <Arduino.h>
+#include <TimeLib.h>
+#include <elapsedMillis.h>
+#include <WII5.h>
+#include <AvgStd.h>
+
+enum WII5BATTERY_STEPS {
+   WII5BATTERY_OFF,
+   WII5BATTERY_ON,
+   WII5BATTERY_MEASURE,
+   WII5BATTERY_STORE,
+   WII5BATTERY_ANALYSE,
+   WII5BATTERY_FINISH
+};
+
+class WII5Battery : public WII5Power {
+	public:
+		WII5Battery() {}
+		virtual WII5_CONTROLLERS controllerId() {return WII5CONTROLLER_DRIVER;}
+		virtual WII5_DRIVERS driverId() {return WII5DRIVER_BATTERY;}
+
+		void begin();
+		void loop();
+
+		void start(bool force = false);
+		void stop(bool force = false);
+
+    bool isRunning();
+
+    elapsedMillis age;
+    int32_t value;
+	protected:
+
+		WII5BATTERY_STEPS step;
+    elapsedMillis stepWait;
+    uint32_t stepCount;
+
+    AvgStd avgBattery1;
+    AvgStd avgBattery2;
+
+    uint16_t scale(uint16_t data, uint16_t d);
+    uint32_t scale(uint32_t data, uint32_t d);
+
+
+};
+
+extern WII5Battery wii5Battery;
+
+#endif