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

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+.vscode/*
+*.swp
+*.bak
+*.old
+*.orig
+*.clang-format

.hgtags

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-ee4999ebdd2d1b54512facafdd03c8a530ea4bfa v1.0

README.md

@@ -4,13 +4,32 @@
 
 ### Component base is very simple:
 
-* Arduino NANO v3 chinese replica
+* Arduino NANO v3 chinese replica (on Atmega-168 chip)
-* 7 segment 4 digit LED indicator with common anode, FYQ-5641BG-21
+* 7 segment 4 digit LED indicator with common anode, FYQ-5641BD-21 (red LEDs)
 * 8 resistors that limiting current on LED segments, 330 Ohms, 0.25 watts
-* RTC Module GEEGROW with DS1307 chip
+* RTC Module GEEGROW with DS1307 chip (very basic, only RTC chip, quartz resonator, button battery, no additional memory chip)
 * 5x7 cm single side prototyping board
 * usb phone charger as power supply
 * 2 push buttons
 * 1 on/off switch
 * Gainta G521G enclosure (92x66.5x28мм)
 * 5m power cord
+
+### Optionally you may need:
+
+* Capasitor with well capacity if your charger has small capasitor on output
+* Fuse, to protect your device
+* DC/DC transformer if you have power supply that gives more than 5 volts or less than 4.5 volts (this will give additional surge protection if your power supply dies, this can happen after 3-5 years of uninterrupted work)
+
+### 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

@@ -1,160 +1,205 @@
-/*  
+/*
- *           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
+ * It uses display module with common anode and DS1307 RTC module to enhance
- *           RTC module to enhance time keeping ability of
+ * time keeping ability of Atmega 328p based Arduino Nano microcontroller and
- *           Atmega 328p based Arduino nano microcontroller and
+ * 2 buttons for adjusting time.
- *           2 buttons for adjusting time.
+ */
- */
+
-
+/* DS1307 lib by FrankieChu for Seeed RTC module, in my case
-/* This software distributed under BSD 2 Clause License
+ * Grove___RTC_DS1307-1.0.0.zip */
-
+#include <DS1307.h>
-Copyright (c) Sergei Fedosoff, All rights reserved.
+#include <SevSeg.h>
-
+
-Redistribution and use in source and binary forms, with or without modification,
+DS1307 clock;
-are permitted provided that the following conditions are met:
+SevSeg Display;
-
+
-Redistributions of source code must retain the above copyright notice, this list
+/* push button stuff */
-of conditions and the following disclaimer. Redistributions in binary form must
+const long initial_delay = 600;   // wait a bit before spin numbers
-reproduce the above copyright notice, this list of conditions and the following
+const long adjust_interval = 200; // delay between consecutive number increments
-disclaimer in the documentation and/or other materials provided with the
+const long bounce_delay = 20;     // contact bounce compensation
-distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+const int hrs_btn = A0;           // put hour adjusting button on A0 lane
-CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+const int min_btn = A1;           // put minute adjusting button on A1 lane
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+volatile bool btn_pushed = false; // is button pushed?
-PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+unsigned long previousPushTimer = 0;
-CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+
-OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+/* dot blinking stuff */
-SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+volatile bool dot = true;
-INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+
-CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+/* time inaccuracy compensation flag */
-IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+volatile bool compflag1 = true;
-OF SUCH DAMAGE.
+volatile bool compflag2 = false;
-*/
+const uint8_t timeSkew = 8;          // assume that clock runs faster than should
-
+volatile bool timeSkewEven = false;  // comp. 1 additional second per 2 days
-#include <SevSeg.h>
+
-#include <Wire.h>
+/* time vars */
-#include <TimeLib.h>
+volatile uint8_t mysecond;
-// DS1307 lib by FrankieChu for Seeed RTC module
+volatile uint8_t myminute;
-#include <DS1307.h>
+volatile uint8_t myhour;
-
+
-DS1307 clock;
+/* rtc sync flag */
-SevSeg Display;
+volatile bool rtcsync = true;
-
+
-unsigned long currentMillis;
+void setup()
-unsigned long previousMillis = 0;
+{
-const long interval = 500;
+	// setup display
-const int hrs_btn = A0;
+	byte hardwareConfig = COMMON_ANODE;
-const int min_btn = A1;
+	byte numDigits = 4;
-bool dot = true;
+	byte digitPins[] = {9, 10, 11, 12};
-uint8_t minutes;
+	byte segmentPins[] = {2, 3, 4, 5, 6, 7, 8, 13};
-uint8_t hours;
+	bool resistorsOnSegments = true; // 8 resistors, 330 Ohms each
-
+	bool updateWithDelays = false;   // Default. Recommended
-void setup()
+
-{
+	/* without it there is visual bug at 0 o'clock, and in current version
-	// setup display
+	 * of SevSeg' setChars() does not dots at all */
-	byte hardwareConfig = COMMON_ANODE;
+	bool leadingZeros = false;
-	byte numDigits = 4;
+
-	byte digitPins[] = {9, 10, 11, 12};
+	Display.begin(hardwareConfig, numDigits, digitPins, segmentPins,
-	byte segmentPins[] = {2, 3, 4, 5, 6, 7, 8, 13};
+	              resistorsOnSegments, updateWithDelays, leadingZeros);
-	bool resistorsOnSegments = true;   // 8 resistors, 330 Ohms each
+	Display.setBrightness(100);
-	bool updateWithDelays = false;     // Default. Recommended
+
-	/* without it there is visual bug at 0 o'clock, and in current version of
+	// setup clock
-	 * SevSeg' setChars() does not dots at all */
+	clock.begin();
-	bool leadingZeros = false;          
+
-
+	// if rtc returns incorrect time, reset it to some default value
-	Display.begin(hardwareConfig, numDigits, digitPins, segmentPins,
+	clock.getTime();
-                      resistorsOnSegments, updateWithDelays, leadingZeros);
+
-	Display.setBrightness(90);
+	if ((clock.hour > 23) || (clock.minute > 59)) {
-
+		clock.fillByYMD(2019, 2, 23); // 23 Feb 2019
-	// setup clock
+		clock.fillByHMS(15, 52, 30);  // 15:52:30"
-	clock.begin();
+		clock.fillDayOfWeek(SAT);     // Saturday
-
+		clock.setTime();              // put date to rtc
-	// if rtc returns incorrect time, reset it to some default value
+	}
-	clock.getTime();
+
-
+	// setup control buttons
-	if (( clock.hour > 23 ) || (clock.minute > 59))
+	pinMode(hrs_btn, INPUT_PULLUP);
-	{
+	pinMode(min_btn, INPUT_PULLUP);
-		clock.fillByYMD(2019,2,23);  // 23 Feb 2013
+	
-		clock.fillByHMS(15,52,30);   // 15:52 30"
+/* Timer stuff
-		clock.fillDayOfWeek(SAT);    // Saturday
+ * timer0 being used in millis() micros() delay() etc, it has 8 bit resolution
-		clock.setTime();             // put date to rtc
+ * 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
-	// setup control buttons
+ */
-	pinMode(hrs_btn, INPUT_PULLUP);
+	// initialize timer1
-	pinMode(min_btn, INPUT_PULLUP);
+	noInterrupts();           // disable all interrupts
-}
+	TCCR1A = 0;
-
+	TCCR1B = 0;
-
+
-void loop()
+	TCNT1 = 34286;            // preload timer 65536-16MHz/256/2Hz
-{
+	TCCR1B |= (1 << CS12);    // 256 prescaler 
-	unsigned long currentMillis = millis();
+	TIMSK1 |= (1 << TOIE1);   // enable timer overflow interrupt
-	char str[4];
+	interrupts();             // enable all interrupts
-	float d;
+}
-	
+
-	if (currentMillis - previousMillis >= interval)
+ISR(TIMER1_OVF_vect)
-	{
+{
-		previousMillis = currentMillis;
+/* Feed clock twice per second */
-
+	TCNT1 = 34286;            // preload timer
-		if (dot == false)
+	// do not read rtc if time beng adjusted by buttons
-		{
+	(btn_pushed) ? rtcsync : rtcsync = true;
-			dot = true;
+
-
+/* Also switch dot */
-			if (digitalRead(hrs_btn) == LOW)
+	if (dot)
-			{
+		dot = false;
-				clock.getTime();
+	else
-				hours = clock.hour + 1;
+		dot = true;
-				(hours > 23)? hours = 0: hours;
+
-				clock.fillByHMS(hours, clock.minute, 0);
+/* time compensation magic */
-				clock.setTime();
+	if ((myhour == 21) and (myminute == 21) and (mysecond == 21)
-			}
+	    and (compflag2)) {
-
+		compflag1 = true;
-			if (digitalRead(min_btn) == LOW)
+		(timeSkewEven) ? timeSkewEven = false : timeSkewEven;
-			{
+	}
-				clock.getTime();
+
-				minutes = clock.minute + 1;
+	if ((myhour == 21) and (myminute == 21) and (mysecond == 23)) {
-				(minutes > 59)? minutes = 0: minutes;
+		compflag1 = false;
-				clock.fillByHMS(clock.hour, minutes, 0);
+		compflag2 = true;
-				clock.setTime();
+	}
-			}
+}
-		}
+
-		else
+void loop()
-		{
+{
-			dot = false;
+	unsigned long currentMillis = millis();
-		}
+
-	}
+/*
-
+ * Let's implement time compenstion for individual rtc module time
-	clock.getTime();
+ * charachteristics. In in my case quartz resonator as inaccurate as
-
+ * about +8.5 seconds per 24 hours
-	// make blinking dot
+ */
-	if (clock.hour > 0)
+	if (compflag1 && compflag2) {
-	{
+		if (timeSkewEven) {
-		if (dot == true) 
+			clock.fillByHMS(myhour, myminute, (mysecond - timeSkew - 1));
-		{
+		} else {
-			Display.setNumber((clock.hour * 100 + clock.minute), 2);
+			clock.fillByHMS(myhour, myminute, (mysecond - timeSkew));
-		}
+		}
-		else
+
-		{
+		clock.setTime();
-			Display.setNumber((clock.hour * 100 + clock.minute));
+		compflag2 = false;
-		}
+	}
-	}
+
-	else
+	if (rtcsync) {
-	{
+		clock.getTime();
-		/* 0 o'clock is an exception, we dont want to see "00.00", we want see
+		mysecond = clock.second;
-		 * "0.00" or "0 00", so we have to use this "hack" */
+		myminute = clock.minute;
-		if (dot == true)
+		myhour = clock.hour;
-		{
+		updateTimeStr(myhour, myminute);
-			d = float(clock.minute) / 100;
+		rtcsync = false;
-			Display.setNumber(d, 2);
+	}
-		}
+
-		else
+	// push button magic
-		{
+	if ((!btn_pushed) and
-			sprintf(str, "%2d%02d", clock.hour, clock.minute);
+	    ((digitalRead(hrs_btn) == LOW) or (digitalRead(min_btn) == LOW))) {
-			Display.setChars(str);
+		if (currentMillis - previousPushTimer >= initial_delay) {
-		}
+			previousPushTimer = currentMillis;
-	}
+			btn_pushed = true;
-
+		}
-	Display.refreshDisplay();
+	}
-}
+
-
+	if (btn_pushed and
-/* vim: set filetype=cpp: */
+	    (digitalRead(hrs_btn) != LOW) and (digitalRead(min_btn) != LOW)) {
+		// compensate possible contact bounce with delay
+		if (currentMillis - previousPushTimer >= bounce_delay) {
+			btn_pushed = false;
+		}
+	}
+
+	if (btn_pushed) {
+		if (currentMillis - previousPushTimer >= adjust_interval) {
+			previousPushTimer = currentMillis;
+
+			if (digitalRead(hrs_btn) == LOW) {
+				myhour++;
+				(myhour > 23) ? myhour = 0 : myhour;
+				clock.fillByHMS(myhour, myminute, 0);
+				clock.setTime();
+			}
+
+			if (digitalRead(min_btn) == LOW) {
+				myminute++;
+				(myminute > 59) ? myminute = 0 : myminute;
+				clock.fillByHMS(myhour, myminute, 0);
+				clock.setTime();
+			}
+		}
+
+		updateTimeStr(myhour, myminute);
+	}
+
+	Display.refreshDisplay();
+}
+
+void updateTimeStr(uint8_t h, uint8_t m)
+{
+	if (dot) {
+		char str[5];
+		sprintf(str, "%2d.%02d", h, m);
+		Display.setChars(str);
+	} else {
+		char str[4];
+		sprintf(str, "%2d%02d", h, m);
+		Display.setChars(str);
+	}
+}
+
+/* vim: set filetype=cpp: */