Single digit clock - method and apparatus
I recently found, at the bottom of a drawer, my forgotten numitron single-tube clock. It has a LiPo battery which still lights up the filaments, but no RTC to actually show time. It has a single button, which activates the display (numitron tube) when pressed. Indeed, some digits flash on, but inconsistently. And, as a clock, one would want to be able to also set the time, which is definitely not possible in this current version.
The required revision consists in:
- adding RTC
- adding a second button
- updating the software (by adding the ability to set the time through buttons)
The method I devised for setting up the time follows this state-machine diagram,
where "Set time" state is part of this bigger picture:
The whole source code file is proudly presented below (as answer to the lots of questions in the above mentioned old post).
/*************************************************************************
* Sketch for direct driving 7-segment numitron IV-9
*
* Segments are defined as follows:
*
* A
* ---
* B | | C
* --- D
* E | | F
* ---
* G
*
* Decimal point/comma is segment H.
* Common pin is wired to Vcc (would be nice to wire it to D11/MOSI
* instead, which is also PWM (for brightness)).
* To light up a segment, just connect it to GND.
*
* To display a digit, ground these Arduino pins:
* 0: 6, 7, 8, 10, 11, 13
* 1: 7, 8
* 2: 6, 8, 10, 11, 12
* 3: 6, 7, 8, 11, 12
* 4: 7, 8, 12, 13
* 5: 6, 7, 11, 12, 13
* 6: 6, 7, 10, 11, 12, 13
* 7: 6, 7, 8
* 8: 6, 7, 8, 10, 11, 12, 13
* 9: 6, 7, 8, 11, 12, 13
*
*************************************************************************/
#include <Arduino.h>
#include <Wire.h>
#include "DS1307.h"
#define _DEBUG_
// arduino pins connected to tube terminals;
// chosen based on the natural positioning of the Numitron tube on Pro Mini board;
#define segA 6 // tube pin 5
#define segB 13 // tube pin 6
#define segC 8 // tube pin 3
#define segD 12 // tube pin 7
#define segE 10 // tube pin 9
#define segF 7 // tube pin 4
#define segG 11 // tube pin 8
#define segH 9 // tube pin 2
// button to initiate the setting up of the time;
#define PIN_BUTTON_SET_TIME 4 // D4
// button to activate the display or to increment the time digit;
#define PIN_BUTTON_ACTIVATE 17 // A3
byte segmentPin[8] = {segA, segB, segC, segD, segE, segF, segG};
byte digits[10][7] =
{
// A B C D E F G
{0, 0, 0, 1, 0, 0, 0}, // 0
{1, 1, 0, 1, 1, 0, 1}, // 1
{0, 1, 0, 0, 0, 1, 0}, // 2
{0, 1, 0, 0, 1, 0, 0}, // 3
{1, 0, 0, 0, 1, 0, 1}, // 4
{0, 0, 1, 0, 1, 0, 0}, // 5
{0, 0, 1, 0, 0, 0, 0}, // 6
{0, 1, 0, 1, 1, 0, 1}, // 7
{0, 0, 0, 0, 0, 0, 0}, // 8
{0, 0, 0, 0, 1, 0, 0} // 9
};
byte state[4][7] =
{
// A B C D E F G
{1, 0, 0, 0, 0, 0, 1}, // H
{1, 0, 1, 0, 0, 0, 1}, // h
{0, 0, 0, 1, 0, 0, 1}, // M
{1, 1, 1, 0, 0, 0, 1}, // m
};
volatile boolean wasTimeEverSet = false;
volatile boolean showingTime = false;
volatile boolean settingTime = false;
byte crtIndex = 0; // 0..3, index in array timeDigits;
byte timeDigits[4] = {0, 1, 2, 3};
int hour = 0;
int minute = 0;
int second = 0;
byte crtValue = 0; // used when setting the time, one digit at a time (for HHMM);
short crtState = -1; // used when setting the time;
boolean newState = false;
void setup()
{
#ifdef _DEBUG_
Serial.begin(9600);
Serial.println("in setup");
#endif
// each of display's 7 segment is connected to an output;
for (byte i=0; i<7; i++)
{
pinMode(segmentPin[i], OUTPUT);
}
// buttons to activate tube and for setting up the time;
pinMode(PIN_BUTTON_ACTIVATE, INPUT_PULLUP);
pinMode(PIN_BUTTON_SET_TIME, INPUT_PULLUP);
blankDisplay();
}
void loop()
{
if (digitalRead(PIN_BUTTON_ACTIVATE) == LOW)
{
#ifdef _DEBUG_
Serial.print("settingTime=");
Serial.println(settingTime);
#endif
delay(200); // debouncing;
if (settingTime)
{
newState = false;
crtValue++;
if (crtValue > 9)
crtValue = 0;
displayValue(crtValue);
#ifdef _DEBUG_
Serial.print ("crtValue=");
Serial.println(crtValue);
#endif
}
else
{
getTimeFromRTC();
splitTime();
// show time as (h)h-mm;
showingTime = true;
}
}
if (digitalRead(PIN_BUTTON_SET_TIME) == LOW)
{
delay(200); // debouncing;
#ifdef _DEBUG_
Serial.print("crtState=");
Serial.println(crtState);
#endif
if (crtState == -1)
{
// user is initiating setting up the time;
settingTime = true;
}
if (settingTime)
{
newState = true;
crtState++;
}
#ifdef _DEBUG_
Serial.print("settingTime=");
Serial.println(settingTime);
#endif
}
if (showingTime)
{
#ifdef _DEBUG_
Serial.print ("show time, digit ");
Serial.println(crtIndex);
#endif
if (crtIndex == 0 && timeDigits[0] == 0)
{
// do not show the leading 0;
}
else
{
if (crtIndex == 2)
{
// show the dash between hours and minutes;
displayDash();
// hold it for a second;
delay(1000);
}
// make the digit flash (otherwise, if 2 consecutive digits are the same, you won't see a difference);
displayDigit(crtIndex);
// hold the digit for a second;
delay(1000);
}
crtIndex++;
if (crtIndex > 3)
{
showingTime = false; // time will show again when button is pressed;
crtIndex = 0;
blankDisplay();
}
}
if (settingTime)
{
if (newState)
{
newState = false;
// need to save the crtValue;
if (crtState > 0)
{
#ifdef _DEBUG_
Serial.print("set value ");
Serial.print(crtValue);
Serial.print(" at index ");
Serial.println(crtState-1);
#endif
timeDigits[crtState-1] = crtValue;
}
if (crtState > 3)
{
settingTime = false;
crtState = -1;
blankDisplay();
#ifdef _DEBUG_
Serial.print("saving time: ");
Serial.print(10 * timeDigits[0] + timeDigits[1]);
Serial.print(":");
Serial.println(10 * timeDigits[2] + timeDigits[3]);
Serial.print("settingTime=");
Serial.println(settingTime);
#endif
// time is set only after all 4 digits (HhMm) were input, that is, after state "m" is left;
setTime(10 * timeDigits[0] + timeDigits[1], 10 * timeDigits[2] + timeDigits[3], 0);
}
else
{
displayCrtState(); // one of the 4: H, h, M, m
// hold it for a bit;
delay(100);
// start setting the value from 0;
crtValue = 0;
}
}
}
}
void displayDigit(byte index)
{
blankDisplay();
delay(100);
byte digit = timeDigits[index];
// turn on the necessary segments of the digit;
for (byte i=0; i<7; i++)
{
digitalWrite(segmentPin[i], digits[digit][i]);
}
}
void displayValue(byte crtValue)
{
blankDisplay();
delay(100);
// turn on the necessary segments;
for (byte i=0; i<7; i++)
{
digitalWrite(segmentPin[i], digits[crtValue][i]);
}
}
void blankDisplay()
{
// turn off all 7 segments;
for (byte i=0; i<7; i++)
{
digitalWrite(segmentPin[i], 1);
}
}
void displayDash()
{
blankDisplay();
delay(100);
digitalWrite(segD, 0);
}
void displayCrtState()
{
#ifdef _DEBUG_
Serial.print ("crt state is ");
Serial.println(crtState);
#endif
blankDisplay();
delay(100);
// turn on the necessary segments of the state/letter;
for (byte i=0; i<7; i++)
{
digitalWrite(segmentPin[i], state[crtState][i]);
}
}
//**********************************************************************************
// Read the entire RTC buffer
//
void getTimeFromRTC()
{
int rtc[7];
RTC_DS1307.get(rtc, true);
// check to avoid glitches;
if (rtc[DS1307_MIN] < 60 && rtc[DS1307_HR] < 24 && rtc[DS1307_SEC] < 60)
{
second = rtc[DS1307_SEC];
minute = rtc[DS1307_MIN];
hour = rtc[DS1307_HR];
}
/*
// check to avoid glitches;
if (rtc[DS1307_YR] <= 2050 && rtc[DS1307_MTH] <= 12 && rtc[DS1307_DATE] <= 31)
{
day = rtc[DS1307_DATE];
month = rtc[DS1307_MTH];
year = rtc[DS1307_YR];
}
*/
// The RTC may have a dead battery or may have never been initialized
// If so, the RTC doesn't run until it is set.
// Here we check once to see if it is running and start it if not.
if (!wasTimeEverSet) {
wasTimeEverSet = true;
if (hour == 0 && minute == 0 && second == 0)
{
// set an arbitrary time to get the RTC going;
setTime(10,23,45);
}
}
#ifdef _DEBUG_
Serial.print("Time is ");
Serial.print(rtc[DS1307_HR]);
Serial.print(":");
Serial.print(rtc[DS1307_MIN]);
Serial.print(":");
Serial.println(rtc[DS1307_SEC]);
#endif
}
//**********************************************************************************
//
void setTime(int hh, int mm, int ss)
{
RTC_DS1307.stop();
RTC_DS1307.set(DS1307_SEC, ss);
RTC_DS1307.set(DS1307_MIN, mm);
RTC_DS1307.set(DS1307_HR, hh);
RTC_DS1307.start();
}
void splitTime()
{
timeDigits[0] = hour / 10;
timeDigits[1] = hour % 10;
timeDigits[2] = minute/10;
timeDigits[3] = minute%10;
}
[original story: Wise time with Arduino]
