--- /dev/null
+/*
+ * MIT License
+ *
+ * Copyright (c) 2025 Raffael Mancini
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Solar time formulas follow the notation from:
+ * https://www.pveducation.org/pvcdrom/properties-of-sunlight/solar-time
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include "local_solar_time_face.h"
+#include "watch.h"
+#include "watch_utility.h"
+#include "filesystem.h"
+
+#if __EMSCRIPTEN__
+#include <emscripten.h>
+#endif
+
+#ifndef M_PI
+#define M_PI 3.14159265358979323846f
+#endif
+
+/* ---------------------------------------------------------------------------
+ * Solar time math (pveducation.org notation)
+ * ---------------------------------------------------------------------------
+ *
+ * LSTM = 15 * ΔTUTC [degrees]
+ * B = (360 / 365) * (d - 81) [degrees] d = day-of-year
+ * EoT = 9.87*sin(2B) - 7.53*cos(B)
+ * - 1.5*sin(B) [minutes]
+ * TC = 4 * (Longitude - LSTM) + EoT [minutes]
+ * LST = LT + TC/60 [hours]
+ * HRA = 15 * (LST - 12) [degrees]
+ * ---------------------------------------------------------------------------
+ */
+
+static movement_location_t _load_location(void) {
+ movement_location_t loc = {0};
+ filesystem_read_file("location.u32", (char *)&loc.reg, sizeof(loc.reg));
+ return loc;
+}
+
+/* Compute and cache EoT and TC. Call when d != state->last_calc_d. */
+static void _compute_daily(local_solar_time_state_t *state, uint16_t d) {
+ /* LSTM — movement_get_current_timezone_offset() returns seconds from UTC */
+ float delta_T_UTC = (float)movement_get_current_timezone_offset() / 3600.0f;
+ float LSTM = 15.0f * delta_T_UTC;
+
+ movement_location_t loc = _load_location();
+ float longitude = (float)(int16_t)loc.bit.longitude / 100.0f;
+
+ /* B in radians for sinf/cosf */
+ float B = (360.0f / 365.0f) * ((float)d - 81.0f) * ((float)M_PI / 180.0f);
+
+ state->EoT = 9.87f * sinf(2.0f * B) - 7.53f * cosf(B) - 1.5f * sinf(B);
+ state->TC = 4.0f * (longitude - LSTM) + state->EoT;
+ state->last_calc_d = d;
+}
+
+/* Recompute if the day-of-year has rolled over. Returns current d. */
+static uint16_t _maybe_recompute(local_solar_time_state_t *state, watch_date_time_t dt) {
+ uint16_t d = watch_utility_days_since_new_year(
+ (uint16_t)(dt.unit.year + WATCH_RTC_REFERENCE_YEAR),
+ dt.unit.month,
+ dt.unit.day
+ );
+ if (d != state->last_calc_d && _load_location().reg != 0) {
+ _compute_daily(state, d);
+ }
+ return d;
+}
+
+/* LST as total seconds since midnight (0..86399).
+ * LST = LT + TC/60 => in seconds: LT_sec + TC*60 */
+static int32_t _lst_seconds(watch_date_time_t dt, float TC) {
+ int32_t lt = (int32_t)dt.unit.hour * 3600
+ + (int32_t)dt.unit.minute * 60
+ + (int32_t)dt.unit.second;
+ int32_t tc = (int32_t)(TC * 60.0f);
+ return ((lt + tc) % 86400 + 86400) % 86400;
+}
+
+static void _update_display(local_solar_time_state_t *state, watch_date_time_t dt) {
+ char buf[14];
+
+ if (_load_location().reg == 0) {
+ watch_display_text(WATCH_POSITION_FULL, "SO no Loc");
+ return;
+ }
+
+ switch (state->mode) {
+
+ case LOCAL_SOLAR_TIME_MODE_LST: {
+ int32_t s = _lst_seconds(dt, state->TC);
+ sprintf(buf, "SO %02d%02d%02d",
+ (int)(s / 3600), (int)((s % 3600) / 60), (int)(s % 60));
+ watch_set_colon();
+ break;
+ }
+
+ case LOCAL_SOLAR_TIME_MODE_NOON: {
+ /* Solar noon: moment when LST = 12:00 → LT_noon = 12h - TC/60 */
+ int32_t s = (int32_t)(( 12.0f - state->TC / 60.0f) * 3600.0f);
+ s = ((s % 86400) + 86400) % 86400;
+ sprintf(buf, "nO %02d%02d ", (int)(s / 3600), (int)((s % 3600) / 60));
+ watch_set_colon();
+ break;
+ }
+
+ case LOCAL_SOLAR_TIME_MODE_HRA: {
+ /* HRA = 15 * (LST - 12); negative = morning, positive = afternoon */
+ int32_t s = _lst_seconds(dt, state->TC);
+ int16_t hra = (int16_t)roundf(15.0f * ((float)s / 3600.0f - 12.0f));
+ sprintf(buf, "Hr %+4d ", (int)hra);
+ watch_clear_colon();
+ break;
+ }
+
+ default:
+ return;
+ }
+
+ watch_display_text(WATCH_POSITION_FULL, buf);
+}
+
+/* ---- Movement callbacks -------------------------------------------------- */
+
+void local_solar_time_face_setup(uint8_t watch_face_index, void **context_ptr) {
+ (void)watch_face_index;
+ if (*context_ptr == NULL) {
+ *context_ptr = malloc(sizeof(local_solar_time_state_t));
+ memset(*context_ptr, 0, sizeof(local_solar_time_state_t));
+ /* last_calc_d == 0 guarantees recomputation on first tick */
+ }
+}
+
+void local_solar_time_face_activate(void *context) {
+ local_solar_time_state_t *state = (local_solar_time_state_t *)context;
+
+#if __EMSCRIPTEN__
+ /* In the simulator the browser exposes lat/lon as JS globals.
+ * Write them to location.u32 if not already set. */
+ int16_t browser_lat = EM_ASM_INT({ return lat; });
+ int16_t browser_lon = EM_ASM_INT({ return lon; });
+ if (browser_lat || browser_lon) {
+ movement_location_t browser_loc = {0};
+ filesystem_read_file("location.u32", (char *)&browser_loc.reg, sizeof(browser_loc.reg));
+ if (browser_loc.reg == 0) {
+ browser_loc.bit.latitude = browser_lat;
+ browser_loc.bit.longitude = browser_lon;
+ filesystem_write_file("location.u32", (char *)&browser_loc.reg, sizeof(browser_loc.reg));
+ }
+ }
+#endif
+
+ /* Force recompute on activation: timezone or location may have changed */
+ state->last_calc_d = 0;
+ watch_date_time_t dt = movement_get_local_date_time();
+ _maybe_recompute(state, dt);
+}
+
+bool local_solar_time_face_loop(movement_event_t event, void *context) {
+ local_solar_time_state_t *state = (local_solar_time_state_t *)context;
+
+ switch (event.event_type) {
+ case EVENT_ACTIVATE:
+ case EVENT_TICK: {
+ watch_date_time_t dt = movement_get_local_date_time();
+ _maybe_recompute(state, dt);
+ _update_display(state, dt);
+ break;
+ }
+
+ case EVENT_ALARM_BUTTON_UP:
+ state->mode = (local_solar_time_mode_t)((state->mode + 1) % LOCAL_SOLAR_TIME_NUM_MODES);
+ {
+ watch_date_time_t dt = movement_get_local_date_time();
+ _update_display(state, dt);
+ }
+ break;
+
+ case EVENT_LOW_ENERGY_UPDATE: {
+ if (!watch_sleep_animation_is_running()) watch_start_sleep_animation(1000);
+ watch_date_time_t dt = movement_get_local_date_time();
+ _maybe_recompute(state, dt);
+ _update_display(state, dt);
+ break;
+ }
+
+ case EVENT_TIMEOUT:
+ state->mode = LOCAL_SOLAR_TIME_MODE_LST;
+ if (_load_location().reg == 0) movement_move_to_face(0);
+ break;
+
+ default:
+ return movement_default_loop_handler(event);
+ }
+
+ return true;
+}
+
+void local_solar_time_face_resign(void *context) {
+ local_solar_time_state_t *state = (local_solar_time_state_t *)context;
+ state->mode = LOCAL_SOLAR_TIME_MODE_LST;
+ watch_clear_colon();
+}
--- /dev/null
+/*
+ * MIT License
+ *
+ * Copyright (c) 2025 Raffael Mancini
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#pragma once
+
+/*
+ * LOCAL SOLAR TIME FACE
+ *
+ * Displays solar time information based on the user's location.
+ * Formulas follow the notation from:
+ * https://www.pveducation.org/pvcdrom/properties-of-sunlight/solar-time
+ *
+ * Variables (pveducation.org notation):
+ * LSTM - Local Standard Time Meridian [degrees] = 15 * ΔTUTC
+ * B - Seasonal angle [degrees] = (360/365) * (d - 81)
+ * EoT - Equation of Time [minutes] = 9.87*sin(2B) - 7.53*cos(B) - 1.5*sin(B)
+ * TC - Time Correction Factor [minutes] = 4*(Longitude - LSTM) + EoT
+ * LST - Local Solar Time [hours] = LT + TC/60
+ * HRA - Hour Angle [degrees] = 15*(LST - 12)
+ *
+ * B, EoT and TC only depend on the day-of-year d, so they are cached
+ * in state and recomputed exactly once per day: the cache key is d itself
+ * (1-366). Zero-initialisation of state guarantees a recompute on first use.
+ *
+ * Requires the location to be set via the Sunrise/Sunset face, stored in
+ * "location.u32" on the filesystem. If no location is set, displays
+ * "SO no Loc".
+ *
+ * Display modes (cycle with the Alarm / start-stop button):
+ * SO HH:MM:SS — Local Solar Time (LST), live seconds display
+ * nO HH:MM — Solar Noon in local clock time
+ * Hr ±DDD — Hour Angle (HRA) in degrees; negative=morning, positive=afternoon
+ */
+
+#include "movement.h"
+
+typedef enum {
+ LOCAL_SOLAR_TIME_MODE_LST = 0, /* Local Solar Time SO HH:MM:SS */
+ LOCAL_SOLAR_TIME_MODE_NOON = 1, /* Solar Noon (local) nO HH:MM */
+ LOCAL_SOLAR_TIME_MODE_HRA = 2, /* Hour Angle Hr ±DDD */
+ LOCAL_SOLAR_TIME_NUM_MODES
+} local_solar_time_mode_t;
+
+typedef struct {
+ local_solar_time_mode_t mode;
+ uint16_t last_calc_d; /* day-of-year (1-366) when EoT/TC were last computed;
+ 0 (zero-init) guarantees recomputation on first tick */
+ float EoT; /* Equation of Time [minutes] */
+ float TC; /* Time Correction Factor [minutes] */
+} local_solar_time_state_t;
+
+void local_solar_time_face_setup(uint8_t watch_face_index, void **context_ptr);
+void local_solar_time_face_activate(void *context);
+bool local_solar_time_face_loop(movement_event_t event, void *context);
+void local_solar_time_face_resign(void *context);
+
+#define local_solar_time_face ((const watch_face_t){ \
+ local_solar_time_face_setup, \
+ local_solar_time_face_activate, \
+ local_solar_time_face_loop, \
+ local_solar_time_face_resign, \
+ NULL, \
+})
projects / sensor-watch.git / commitdiff