Update README.md

* Poll RTC by trigger, set via ISR
* Change blink state by trigger, set via ISR
* Set time compensation trigger in ISR
* Refresh clock by timer
* Re-calculate displayed time only ater rtcsync or when time adjusted by buttons
* Simplify draw algo

.gitignore

@@ -0,0 +1,6 @@
+.vscode/*
+*.swp
+*.bak
+*.old
+*.orig
+*.clang-format

README.md

@@ -12,8 +12,6 @@
 * 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
 
@@ -26,3 +24,12 @@
 ### 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

@@ -1,35 +1,20 @@
-/* 7 Segment 4 Digits clock with digit point separator.
+/*
+ * 7 Segment 4 Digits clock with digit point separator
  *
- * It uses display module with common anode and DS1307/DS3231 RTC module to
- * enhance time keeping ability of Atmega 328p based Arduino Nano 
- * microcontroller and 2 buttons for adjusting time. */
+ * It uses display module with common anode and DS1307 RTC module to enhance
+ * time keeping ability of Atmega 328p based Arduino Nano microcontroller and
+ * 2 buttons for adjusting time.
+ */
 
-/* uRTCLib
- * https://github.com/Naguissa/uRTCLib
- * it has support for both DS1307 and DS3231, that I have.
- * It is more fat than ds1307-dedicated or ds3231-dedicated lib, but I do not
- * want to re-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.  */
+/* DS1307 lib by FrankieChu for Seeed RTC module, in my case
+ * Grove___RTC_DS1307-1.0.0.zip */
+#include <DS1307.h>
 #include <SevSeg.h>
 
-/* Disable time compensation.
- * At last 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;
+DS1307 clock;
 SevSeg Display;
 
-// Push button stuff.
+/* push button stuff */
 const long initial_delay = 600;   // wait a bit before spin numbers
 const long adjust_interval = 200; // delay between consecutive number increments
 const long bounce_delay = 20;     // contact bounce compensation
@@ -38,187 +23,131 @@ const int min_btn = A1;           // put minute adjusting button on A1 lane
 volatile bool btn_pushed = false; // is button pushed?
 unsigned long previousPushTimer = 0;
 
-// Dot blinking stuff.
+/* dot blinking stuff */
 volatile bool dot = true;
 
-#ifdef TIMECOMP
-// Time inaccuracy compensation flag.
+/* time inaccuracy compensation flag */
 volatile bool compflag1 = true;
 volatile bool compflag2 = false;
-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
+const uint8_t timeSkew = 8;          // assume that clock runs faster than should
+volatile bool timeSkewEven = false;  // comp. 1 additional second per 2 days
 
-// Ambient light compensation aka night mode.
-const int photoPin = A2;
-volatile bool measureAmbLight = true;
-unsigned int ambLight = 0;           // Actual value.
-unsigned long previousLightTimer = 0;
-const long refresh_interval = 40;    // Refresh rate 25Hz.
-
-// Time vars.
+/* time vars */
 volatile uint8_t mysecond;
 volatile uint8_t myminute;
 volatile uint8_t myhour;
 
-// RTC sync flag.
+/* rtc sync flag */
 volatile bool rtcsync = true;
 
 void setup()
 {
-	// Setup display.
+	// setup display
 	byte hardwareConfig = COMMON_ANODE;
 	byte numDigits = 4;
 	byte digitPins[] = {9, 10, 11, 12};
 	byte segmentPins[] = {2, 3, 4, 5, 6, 7, 8, 13};
 	bool resistorsOnSegments = true; // 8 resistors, 330 Ohms each
-	/* 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;
+	bool updateWithDelays = false;   // Default. Recommended
 
-	/* Without it there is visual bug at 0 o'clock, and in current version
-	 * of SevSeg' setChars() does not dots at all. */
+	/* without it there is visual bug at 0 o'clock, and in current version
+	 * of SevSeg' setChars() does not dots at all */
 	bool leadingZeros = false;
 
 	Display.begin(hardwareConfig, numDigits, digitPins, segmentPins,
 	              resistorsOnSegments, updateWithDelays, leadingZeros);
 	Display.setBrightness(100);
 
-	// Init i2c bus and setup clock address.
-	Wire.begin();
-	clock.set_rtc_address(0x68);
+	// setup clock
+	clock.begin();
 
-	// If rtc returns incorrect time, reset it to some default values.
-	clock.refresh();
+	// if rtc returns incorrect time, reset it to some default value
+	clock.getTime();
 
-	if (clock.lostPower()) {
-		clock.set(30, 52, 15, 6, 23, 2, 19); // Saturday, 23 Feb 2019 15:52:30
-		clock.lostPowerClear();
+	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
-	}
-
-	/* In case of ds1307 this will be noop, but ds3231/ds3232 sometimes does
-	 * not enable battery by default. */
-	clock.enableBattery();
-
-	// Setup control buttons.
+	// setup control buttons
 	pinMode(hrs_btn, INPUT_PULLUP);
 	pinMode(min_btn, INPUT_PULLUP);
-
-	/* Timer stuff.
-	 * timer0 being used in millis() micros() delay() etc, it has 8 bit resolution.
-	 * timer2 being used in analogWrite() tone() notone(), it has 8 bit resolution.
-	 * timer1 being used in servo lib has 16 bit resolution.
-	 * We'll use timer1, since we have no mechanical parts and don't need servo lib */
-
-	// Initialize timer1.
-	noInterrupts();           // Disable all interrupts.
+	
+/* Timer stuff
+ * timer0 being used in millis() micros() delay() etc, it has 8 bit resolution
+ * timer2 being used in analogWrite() tone() notone(), it has 8 bit resolution
+ * timer1 being used in servo lib has 16 bit resolution
+ * We'll use timer1, since we have no mechanical parts and don't need servo lib
+ */
+	// initialize timer1
+	noInterrupts();           // disable all interrupts
 	TCCR1A = 0;
 	TCCR1B = 0;
 
-	TCNT1 = 34286;            // Preload timer 65536-16MHz/256/2Hz
+	TCNT1 = 34286;            // preload timer 65536-16MHz/256/2Hz
 	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);
+	TIMSK1 |= (1 << TOIE1);   // enable timer overflow interrupt
+	interrupts();             // enable all interrupts
 }
 
 ISR(TIMER1_OVF_vect)
 {
-	// Feed clock twice per second.
-	TCNT1 = 34286;            // Preload timer.
-	// Do not read rtc if time beng adjusted by buttons.
+/* Feed clock twice per second */
+	TCNT1 = 34286;            // preload timer
+	// do not read rtc if time beng adjusted by buttons
 	(btn_pushed) ? rtcsync : rtcsync = true;
 
-	// Also switch dot.
+/* Also switch dot */
 	if (dot)
 		dot = false;
 	else
 		dot = true;
 
-#ifdef TIMECOMP
-	// Time compensation magic.
+/* 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 compensation for individual rtc module time
-	 * characteristics. In in my case quartz resonator as inaccurate as
-	 * about +9.5 seconds per 24 hours. */
+/*
+ * 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
+ */
 	if (compflag1 && compflag2) {
-#ifdef OFIVECOMP
 		if (timeSkewEven) {
-			clock.set(
-				(mysecond - timeSkew - 1),
-				clock.minute(),
-				clock.hour(),
-				clock.dayOfWeek(),
-				clock.day(),
-				clock.month(),
-				clock.year()
-			);
+			clock.fillByHMS(myhour, myminute, (mysecond - timeSkew - 1));
 		} else {
-#endif
-			clock.set(
-				(mysecond - timeSkew),
-				clock.minute(),
-				clock.hour(),
-				clock.dayOfWeek(),
-				clock.day(),
-				clock.month(),
-				clock.year()
-			);
-#ifdef OFIVECOMP
+			clock.fillByHMS(myhour, myminute, (mysecond - timeSkew));
 		}
-#endif
 
+		clock.setTime();
 		compflag2 = false;
 	}
-#endif
 
 	if (rtcsync) {
-		clock.refresh();
-		mysecond = clock.second();
-		myminute = clock.minute();
-		myhour = clock.hour();
+		clock.getTime();
+		mysecond = clock.second;
+		myminute = clock.minute;
+		myhour = clock.hour;
 		updateTimeStr(myhour, myminute);
 		rtcsync = false;
 	}
 
-	// Push button magic.
+	// push button magic
 	if ((!btn_pushed) and
 	    ((digitalRead(hrs_btn) == LOW) or (digitalRead(min_btn) == LOW))) {
 		if (currentMillis - previousPushTimer >= initial_delay) {
@@ -242,81 +171,21 @@ void loop()
 			if (digitalRead(hrs_btn) == LOW) {
 				myhour++;
 				(myhour > 23) ? myhour = 0 : myhour;
-				clock.set(
-					0,
-					myminute,
-					myhour,
-					clock.dayOfWeek(),
-					clock.day(),
-					clock.month(),
-					clock.year()
-				);
+				clock.fillByHMS(myhour, myminute, 0);
+				clock.setTime();
 			}
 
 			if (digitalRead(min_btn) == LOW) {
 				myminute++;
 				(myminute > 59) ? myminute = 0 : myminute;
-				clock.set(
-					0,
-					myminute,
-					myhour,
-					clock.dayOfWeek(),
-					clock.day(),
-					clock.month(),
-					clock.year()
-				);
+				clock.fillByHMS(myhour, myminute, 0);
+				clock.setTime();
 			}
 		}
 
 		updateTimeStr(myhour, myminute);
 	}
 
-	if ((currentMillis - previousLightTimer >= refresh_interval) or
-	    (previousLightTimer > currentMillis)) { // millis() reset every ~49 days
-		previousLightTimer = currentMillis;
-		ambLight = analogRead(photoPin);
-
-		/* 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
-		 * characteristics 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);
-		}
-	}
-
 	Display.refreshDisplay();
 }
 
@@ -333,5 +202,4 @@ void updateTimeStr(uint8_t h, uint8_t m)
 	}
 }
 
-
 /* vim: set filetype=cpp: */