Migrate Grove RTC DS1307 -> uRTCLib

* move Time Compensation feature under define
* translte last few eol to unix style
* make correction: in my case with bad chrystal rtc runs faster about
  9.5 seconds per day

README.md

@@ -12,6 +12,8 @@
 * usb phone charger as power supply
 * 2 push buttons
 * 1 on/off switch
+* 1 photoresistor
+* 1 resistor to make secund shoulder of photosensitive "bridge", 10 kOhms, 0.25 watts
 * Gainta G521G enclosure (92x66.5x28мм)
 * 5m power cord
 
@@ -24,12 +26,3 @@
 ### Additional Notes:
 
 My RTC module is not very accurate due to bad quartz chrystal calibration, looks like it is not exactly 32768 Hz and clock runs faster than it should be, giving about 5-8 seconds runaway per day. So i have to implement time correction in software (temperature changes during day/month/year is not very big - about 10 degrees Celsius, so we can use software compensation without thermal compensation).
-
-This project split into 2 branches:
-
-* **default** that contains generic clock without any additional elements
-* **photoresistor** that contains additional hardware - photocell bridge - and software algorithm that compensates ambient light sensed by photocell basing on LED display charachteristics.
-
-### Stable tags for branches:
-v1.6 - default
-v1.7 - photoresistor

simpleclock.ino

@@ -6,12 +6,33 @@
  * 2 buttons for adjusting time.
  */
 
-/* DS1307 lib by FrankieChu for Seeed RTC module, in my case
- * Grove___RTC_DS1307-1.0.0.zip */
-#include <DS1307.h>
+/*
+ * uRTCLib
+ * https://github.com/Naguissa/uRTCLib
+ * it has support for both DS1307 and DS3231, that i own.
+ * It is more fat than ds1307-dedicated or ds3231-dedicated lib, but i do not
+ * want to invent wheel if i have one.
+ */
+#include <uRTCLib.h>
+
+/*
+ * SevSeg
+ * https://github.com/DeanIsMe/SevSeg
+ * it has simple api and ideally works in my case
+ */
 #include <SevSeg.h>
 
-DS1307 clock;
+/* disable time compensation
+ * as we borrow more accurate chrystal and solder it to rtc breakboard
+ */
+//#define TIMECOMP
+/* 0.5 second/day compensation flag */
+//#define OFIVECOMP
+
+#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
+#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
+
+uRTCLib clock;
 SevSeg Display;
 
 /* push button stuff */
@@ -26,11 +47,24 @@ unsigned long previousPushTimer = 0;
 /* dot blinking stuff */
 volatile bool dot = true;
 
+#ifdef TIMECOMP
 /* time inaccuracy compensation flag */
 volatile bool compflag1 = true;
 volatile bool compflag2 = false;
-const uint8_t timeSkew = 8;          // assume that clock runs faster than should
+const uint8_t timeSkew = 9;          // assume that clock runs faster than should
+#ifdef OFIVECOMP
 volatile bool timeSkewEven = false;  // comp. 1 additional second per 2 days
+#endif
+#endif
+
+/* ambient light compensation aka night mode */
+const int photoPin = A2;
+volatile bool measureAmbLight = true;
+unsigned int ambLight = 0;           // actual value
+unsigned int ambLight2 = 0;          // previous med. value
+unsigned int ambLight3 = 0;          // pre-previous med. value
+unsigned long previousLightTimer = 0;
+const long refresh_interval = 40;    // refresh rate 25Hz
 
 /* time vars */
 volatile uint8_t mysecond;
@@ -48,7 +82,12 @@ void setup()
 	byte digitPins[] = {9, 10, 11, 12};
 	byte segmentPins[] = {2, 3, 4, 5, 6, 7, 8, 13};
 	bool resistorsOnSegments = true; // 8 resistors, 330 Ohms each
-	bool updateWithDelays = false;   // Default. Recommended
+	/* updateWithDelays defaults to false and it is recommended value,
+	 * but i was unable to make my display to change brightness notably with
+	 * recommended value, so i have to use updateWithDelays=true,
+	 * in this case brightness gets changed.
+	 */
+	bool updateWithDelays = true;
 
 	/* without it there is visual bug at 0 o'clock, and in current version
 	 * of SevSeg' setChars() does not dots at all */
@@ -59,16 +98,14 @@ void setup()
 	Display.setBrightness(100);
 
 	// setup clock
-	clock.begin();
+	Wire.begin();
+	clock.set_rtc_address(0x68);
 
 	// if rtc returns incorrect time, reset it to some default value
-	clock.getTime();
+	clock.refresh();
 
-	if ((clock.hour > 23) || (clock.minute > 59)) {
-		clock.fillByYMD(2019, 2, 23); // 23 Feb 2019
-		clock.fillByHMS(15, 52, 30);  // 15:52:30"
-		clock.fillDayOfWeek(SAT);     // Saturday
-		clock.setTime();              // put date to rtc
+	if ((clock.hour() > 23) || (clock.minute() > 59)) {
+		clock.set(30, 52, 15, 6, 23, 2, 19); // Saturday, 23 Feb 2019 15:52:30
 	}
 
 	// setup control buttons
@@ -90,6 +127,18 @@ void setup()
 	TCCR1B |= (1 << CS12);    // 256 prescaler 
 	TIMSK1 |= (1 << TOIE1);   // enable timer overflow interrupt
 	interrupts();             // enable all interrupts
+
+/* increase sampling rate of analogRead()
+ * by setting an ADC prescale from 128 to 16, so it takes less time to read
+ * sensor
+ */
+	sbi(ADCSRA, ADPS2);
+	cbi(ADCSRA, ADPS1);
+	cbi(ADCSRA, ADPS0);
+
+	// setup ambient brigtness sensor
+	pinMode(photoPin, INPUT);
+	ambLight = analogRead(photoPin);
 }
 
 ISR(TIMER1_OVF_vect)
@@ -105,44 +154,69 @@ ISR(TIMER1_OVF_vect)
 	else
 		dot = true;
 
+#ifdef TIMECOMP
 /* time compensation magic */
 	if ((myhour == 21) and (myminute == 21) and (mysecond == 21)
 	    and (compflag2)) {
 		compflag1 = true;
+#ifdef OFIVECOMP
 		(timeSkewEven) ? timeSkewEven = false : timeSkewEven;
+#endif
 	}
 
 	if ((myhour == 21) and (myminute == 21) and (mysecond == 23)) {
 		compflag1 = false;
 		compflag2 = true;
 	}
+#endif
 }
 
 void loop()
 {
 	unsigned long currentMillis = millis();
 
+#ifdef TIMECOMP
 /*
  * Let's implement time compenstion for individual rtc module time
  * charachteristics. In in my case quartz resonator as inaccurate as
- * about +8.5 seconds per 24 hours
+ * about +9.5 seconds per 24 hours
  */
 	if (compflag1 && compflag2) {
+#ifdef OFIVECOMP
 		if (timeSkewEven) {
-			clock.fillByHMS(myhour, myminute, (mysecond - timeSkew - 1));
+			clock.set(
+				(mysecond - timeSkew - 1),
+				clock.minute(),
+				clock.hour(),
+				clock.dayOfWeek(),
+				clock.day(),
+				clock.month(),
+				clock.year()
+			);
 		} else {
-			clock.fillByHMS(myhour, myminute, (mysecond - timeSkew));
+#endif
+			clock.set(
+				(mysecond - timeSkew),
+				clock.minute(),
+				clock.hour(),
+				clock.dayOfWeek(),
+				clock.day(),
+				clock.month(),
+				clock.year()
+			);
+#ifdef OFIVECOMP
 		}
+#endif
 
-		clock.setTime();
 		compflag2 = false;
 	}
+#endif
 
 	if (rtcsync) {
-		clock.getTime();
-		mysecond = clock.second;
-		myminute = clock.minute;
-		myhour = clock.hour;
+		clock.refresh();
+		mysecond = clock.second();
+		myminute = clock.minute();
+		myhour = clock.hour();
 		updateTimeStr(myhour, myminute);
 		rtcsync = false;
 	}
@@ -171,21 +245,86 @@ void loop()
 			if (digitalRead(hrs_btn) == LOW) {
 				myhour++;
 				(myhour > 23) ? myhour = 0 : myhour;
-				clock.fillByHMS(myhour, myminute, 0);
-				clock.setTime();
+				clock.set(
+					0,
+					myminute,
+					myhour,
+					clock.dayOfWeek(),
+					clock.day(),
+					clock.month(),
+					clock.year()
+				);
 			}
 
 			if (digitalRead(min_btn) == LOW) {
 				myminute++;
 				(myminute > 59) ? myminute = 0 : myminute;
-				clock.fillByHMS(myhour, myminute, 0);
-				clock.setTime();
+				clock.set(
+					0,
+					myminute,
+					myhour,
+					clock.dayOfWeek(),
+					clock.day(),
+					clock.month(),
+					clock.year()
+				);
 			}
 		}
 
 		updateTimeStr(myhour, myminute);
 	}
 
+	if ((currentMillis - previousLightTimer >= refresh_interval) or
+	    (previousLightTimer > currentMillis)) { // millis() reset every ~49 days
+		previousLightTimer = currentMillis;
+		ambLight = analogRead(photoPin);
+		ambLight = (ambLight + ambLight2 + ambLight3) / 3;
+
+/* Ambient light compensation
+ * ambLight can be in range of 0..1023, if it 910+, it has point to use
+ * fullbright.
+ * Use table comparsion (not function of ambLight) because of non-linear
+ * charachteristics of led indicator, that cannot be described via simple
+ * formula.
+ */
+		if (ambLight >= 910) {
+			Display.setBrightness(100);
+		} else if ((ambLight < 900) and (ambLight >= 860)) {
+			Display.setBrightness(75);
+		} else if ((ambLight < 850) and (ambLight >= 810)) { 
+			Display.setBrightness(45);
+		} else if ((ambLight < 800) and (ambLight >= 760)) {
+			Display.setBrightness(25);
+		} else if ((ambLight < 750) and (ambLight >= 710)) {
+			Display.setBrightness(18);
+		} else if ((ambLight < 700) and (ambLight >= 660)) {
+			Display.setBrightness(12);
+		} else if ((ambLight < 650) and (ambLight >= 610)) {
+			Display.setBrightness(10);
+		} else if ((ambLight < 600) and (ambLight >= 560)) {
+			Display.setBrightness(7);
+		} else if ((ambLight < 550) and (ambLight >= 410)) {
+			Display.setBrightness(4);
+		} else if ((ambLight < 400) and (ambLight >= 360)) {
+			Display.setBrightness(0);
+		} else if ((ambLight < 350) and (ambLight >= 310)) {
+			Display.setBrightness(-3);
+		} else if ((ambLight < 300) and (ambLight >= 260)) {
+			Display.setBrightness(-6);
+		} else if ((ambLight < 250) and (ambLight >= 210)) {
+			Display.setBrightness(-10);
+		} else if ((ambLight < 200) and (ambLight >= 160)) {
+			Display.setBrightness(-14);
+		} else if ((ambLight < 150) and (ambLight >= 110)) {
+			Display.setBrightness(-18);
+		} else if (ambLight < 100) {
+			Display.setBrightness(-22);
+		}
+
+		ambLight3 = ambLight2;
+		ambLight2 = ambLight;
+	}
+
 	Display.refreshDisplay();
 }
 
@@ -202,4 +341,5 @@ void updateTimeStr(uint8_t h, uint8_t m)
 	}
 }
 
+
 /* vim: set filetype=cpp: */