sets the initial brightness based on the time

GPSSpeedMultiCore.ino

@@ -5,6 +5,7 @@
 #include "Adafruit_LEDBackpack.h"                       //for screen
 #include <stdlib.h>
 #include <atomic>
+#include <SolarCalculator.h>  //for determining startup brightness
 #define DISPLAY_ADDRESS 0x70  //I2C address of screen
 #define GPS_WAIT_TIME 1100
 #define GPS_UPDATE_FREQUENCY 10  //GPS update frequency per sec
@@ -13,6 +14,13 @@
 
 //GPS
 SFE_UBLOX_GPS myGPS;
+double lat = 0;
+double lng = 0;
+int tzOff = 12;                             //local TZ offset
+bool centuryBit;                            //needed to get month from RTC
+double az, elev;                            //for sun location in the sky
+double transit, sunrise, sunset;            //sun related times
+double civilTransit, civilRiise, civilSet;  //astro related times
 
 //threading
 std::atomic<float> speed(0);
@@ -29,10 +37,11 @@ unsigned long timeOfLastFix = 0UL;
 
 //button
 volatile bool buttonPushed = false;
-volatile int screenBrightnessButton = 15;
+volatile int ScreenBrightnessUser = 15;
-volatile int screenBrightnessCurrent = screenBrightnessButton;
+volatile int screenBrightnessCurrent = ScreenBrightnessUser;
 volatile unsigned long lastButtonPush = 0UL;
 
+
 void chageBrightness() {
   if (millis() - lastButtonPush > DEBOUNCE_DELAY) {
     buttonPushed = true;
@@ -42,14 +51,14 @@ void chageBrightness() {
 
 void connectGPS() {  //need to do this everytime the GPS turns back on
   do {               //set gps to 115200 baudrate code comes from sparkfun examples
-    Serial.println("GNSS: trying 115200 baud");
+                     // Serial.println("GNSS: trying 115200 baud");
     Serial1.begin(115200);
     if (myGPS.begin(Serial1) == true) break;
     delay(100);
-    Serial.println("GNSS: trying 9600 baud");
+    //Serial.println("GNSS: trying 9600 baud");
     Serial1.begin(9600);
     if (myGPS.begin(Serial1) == true) {
-      Serial.println("GNSS: connected at 9600 baud, switching to 115200");
+      //  Serial.println("GNSS: connected at 9600 baud, switching to 115200");
       myGPS.setSerialRate(115200);
       delay(100);
     } else {
@@ -62,18 +71,33 @@ void connectGPS() {  //need to do this everytime the GPS turns back on
   myGPS.setDynamicModel(DYN_MODEL_AUTOMOTIVE);         //set dynamic model of GPS to automotive to more accutate results
 }
 
+bool setStartBrightness() {
+  while (!(myGPS.getFixType() > 0)) {}
+  double GPSTime=myGPS.getHour()+(myGPS.getMinute()/60);
+
+  //get sunset time
+  calcSunriseSunset(myGPS.getYear(), myGPS.getMonth(), myGPS.getDay(), lat, lng, transit, sunrise, sunset);
+  //get civilSet time
+  calcCivilDawnDusk(myGPS.getYear(), myGPS.getMonth(), myGPS.getDay(), lat, lng, civilTransit, civilRiise, civilSet);
+
+  if(GPSTime<sunset){
+    screenBrightnessCurrent=15;
+  } else if ((GPSTime>sunrise)&&(GPSTime<civilSet)){
+    screenBrightnessCurrent=MIDDLE_SCREEN_BRIGHTNESS;
+  } else if (GPSTime>civilSet){
+    screenBrightnessCurrent=0;
+  }
+  disp.setBrightness(screenBrightnessCurrent);
+  return true;
+}
+
 void setup() {
   //setup screen
   Wire.setSCL(17);
   Wire.setSDA(16);
   //Wire.setClock(100000);
   disp.begin(DISPLAY_ADDRESS);
-  disp.setBrightness(screenBrightnessButton);
+  disp.setBrightness(ScreenBrightnessUser);
-  disp.clear();
-  disp.writeDigitAscii(0, 71);  //"G"
-  disp.writeDigitAscii(1, 80);  //"P"
-  disp.writeDigitAscii(2, 83);  //"S"
-  disp.writeDisplay();
 
   //screen brightness
   pinMode(20, INPUT_PULLUP);
@@ -86,30 +110,29 @@ void setup1() {
   Serial1.setRX(1);
   Serial1.setTX(0);
   connectGPS();
+  setStartBrightness();
 }
 
 void loop() {
-
-
   //change brightness
   if (buttonPushed == true) {
-    if (screenBrightnessButton == 15) {
+    if (ScreenBrightnessUser == 15) {
-      screenBrightnessButton = MIDDLE_SCREEN_BRIGHTNESS;
+      ScreenBrightnessUser = MIDDLE_SCREEN_BRIGHTNESS;
-    } else if (screenBrightnessButton == MIDDLE_SCREEN_BRIGHTNESS) {
+    } else if (ScreenBrightnessUser == MIDDLE_SCREEN_BRIGHTNESS) {
-      screenBrightnessButton = 0;
+      ScreenBrightnessUser = 0;
     } else {
-      screenBrightnessButton = 15;
+      ScreenBrightnessUser = 15;
     }
-    disp.setBrightness(screenBrightnessButton);
+    disp.setBrightness(ScreenBrightnessUser);
-    screenBrightnessCurrent=screenBrightnessButton;
+    screenBrightnessCurrent = ScreenBrightnessUser;
     buttonPushed = false;
   }
 
   disp.clear();
   if (gpsFixType.load() > 0) {
-    if (screenBrightnessCurrent != screenBrightnessButton){
+    if (screenBrightnessCurrent != ScreenBrightnessUser) {
-      disp.setBrightness(screenBrightnessButton);
+      disp.setBrightness(ScreenBrightnessUser);
-      screenBrightnessCurrent=screenBrightnessButton;
+      screenBrightnessCurrent = ScreenBrightnessUser;
     }
     timeOfLastFix = millis();  //reset no gps screen display
     int temp = speed.load() * 10;
@@ -128,9 +151,9 @@ void loop() {
     disp.writeDigitAscii(2, 48 + digit2, true);
     disp.writeDigitAscii(3, 48 + digit3);
   } else {
-    if (screenBrightnessCurrent!=0){
+    if (screenBrightnessCurrent != 0) {
       disp.setBrightness(0);
-      screenBrightnessCurrent=0;
+      screenBrightnessCurrent = 0;
     }
     unsigned long currentTime = millis();
     unsigned long timeSinceLastFIx = timeOfLastFix - currentTime;

sunriseSunset.h

@@ -0,0 +1,142 @@
+ 
+#include <math.h>
+//#define PI 3.1415926
+#define ZENITH -.83
+
+/* zenith calc
+offical      = 90 degrees 50'
+civil        = 96 degrees
+nautical     = 102 degrees
+astronomical = 108 degrees
+http://edwilliams.org/sunrise_sunset_algorithm.htm
+*/
+float calculateSunrise(int year,int month,int day,float lat, float lng,int localOffset, int daylightSavings) {
+    /*
+    localOffset will be <0 for western hemisphere and >0 for eastern hemisphere
+    daylightSavings should be 1 if it is in effect during the summer otherwise it should be 0
+    */
+    //1. first calculate the day of the year
+    float N1 = floor(275 * month / 9);
+    float N2 = floor((month + 9) / 12);
+    float N3 = (1 + floor((year - 4 * floor(year / 4) + 2) / 3));
+    float N = N1 - (N2 * N3) + day - 30;
+
+    //2. convert the longitude to hour value and calculate an approximate time
+    float lngHour = lng / 15.0;      
+    float t = N + ((6 - lngHour) / 24);   //if rising time is desired:
+    //float t = N + ((18 - lngHour) / 24)   //if setting time is desired:
+
+    //3. calculate the Sun's mean anomaly   
+    float M = (0.9856 * t) - 3.289;
+
+    //4. calculate the Sun's true longitude
+    float L = fmod(M + (1.916 * sin((PI/180)*M)) + (0.020 * sin(2 *(PI/180) * M)) + 282.634,360.0);
+
+    //5a. calculate the Sun's right ascension      
+    float RA = fmod(180/PI*atan(0.91764 * tan((PI/180)*L)),360.0);
+
+    //5b. right ascension value needs to be in the same quadrant as L   
+    float Lquadrant  = floor( L/90) * 90;
+    float RAquadrant = floor(RA/90) * 90;
+    RA = RA + (Lquadrant - RAquadrant);
+
+    //5c. right ascension value needs to be converted into hours   
+    RA = RA / 15;
+
+    //6. calculate the Sun's declination
+    float sinDec = 0.39782 * sin((PI/180)*L);
+    float cosDec = cos(asin(sinDec));
+
+    //7a. calculate the Sun's local hour angle
+    float cosH = (sin((PI/180)*ZENITH) - (sinDec * sin((PI/180)*lat))) / (cosDec * cos((PI/180)*lat));
+    /*   
+    if (cosH >  1) 
+    the sun never rises on this location (on the specified date)
+    if (cosH < -1)
+    the sun never sets on this location (on the specified date)
+    */
+
+    //7b. finish calculating H and convert into hours
+    float H = 360 - (180/PI)*acos(cosH);   //   if if rising time is desired:
+    //float H = acos(cosH) //   if setting time is desired:      
+    H = H / 15;
+
+    //8. calculate local mean time of rising/setting      
+    float T = H + RA - (0.06571 * t) - 6.622;
+
+    //9. adjust back to UTC
+    float UT = fmod(T - lngHour,24.0);
+
+    //10. convert UT value to local time zone of latitude/longitude
+    return UT + localOffset + daylightSavings;
+
+    }
+    float calculateSunset(int year,int month,int day,float lat, float lng,int localOffset, int daylightSavings) {
+    /*
+    localOffset will be <0 for western hemisphere and >0 for eastern hemisphere
+    daylightSavings should be 1 if it is in effect during the summer otherwise it should be 0
+    */
+    //1. first calculate the day of the year
+    float N1 = floor(275 * month / 9);
+    float N2 = floor((month + 9) / 12);
+    float N3 = (1 + floor((year - 4 * floor(year / 4) + 2) / 3));
+    float N = N1 - (N2 * N3) + day - 30;
+
+    //2. convert the longitude to hour value and calculate an approximate time
+    float lngHour = lng / 15.0;      
+    //float t = N + ((6 - lngHour) / 24);   //if rising time is desired:
+    float t = N + ((18 - lngHour) / 24);  //if setting time is desired:
+
+    //3. calculate the Sun's mean anomaly   
+    float M = (0.9856 * t) - 3.289;
+
+    //4. calculate the Sun's true longitude
+    float L = fmod(M + (1.916 * sin((PI/180)*M)) + (0.020 * sin(2 *(PI/180) * M)) + 282.634,360.0);
+
+    //5a. calculate the Sun's right ascension      
+    float RA = fmod(180/PI*atan(0.91764 * tan((PI/180)*L)),360.0);
+
+    //5b. right ascension value needs to be in the same quadrant as L   
+    float Lquadrant  = floor( L/90) * 90;
+    float RAquadrant = floor(RA/90) * 90;
+    RA = RA + (Lquadrant - RAquadrant);
+
+    //5c. right ascension value needs to be converted into hours   
+    RA = RA / 15;
+
+    //6. calculate the Sun's declination
+    float sinDec = 0.39782 * sin((PI/180)*L);
+    float cosDec = cos(asin(sinDec));
+
+    //7a. calculate the Sun's local hour angle
+    float cosH = (sin((PI/180)*ZENITH) - (sinDec * sin((PI/180)*lat))) / (cosDec * cos((PI/180)*lat));
+    /*   
+    if (cosH >  1) 
+    the sun never rises on this location (on the specified date)
+    if (cosH < -1)
+    the sun never sets on this location (on the specified date)
+    */
+
+    //7b. finish calculating H and convert into hours
+    //float H = 360 - (180/PI)*acos(cosH);   //   if if rising time is desired:
+    float H = (180/PI)*acos(cosH);//   if setting time is desired:      
+    H = H / 15;
+
+    //8. calculate local mean time of rising/setting      
+    float T = H + RA - (0.06571 * t) - 6.622;
+
+    //9. adjust back to UTC
+    float UT = fmod(T - lngHour,24.0);
+
+    //10. convert UT value to local time zone of latitude/longitude
+    return UT + localOffset + daylightSavings;
+
+    }
+/*
+    void printSunrise() {
+    float localT = calculateSunrise(args);
+    double hours;
+    float minutes = modf(localT,&hours)*60;
+    printf("%.0f:%.0f",hours,minutes);
+    }
+    */