PIC16F819 DymoClock
A creative LED clock using Dymo label tape numbers
Take a piece of wood, drill 27 holes, insert LEDs, and use a Dymo labeler for the numbers.
Overview
Take a piece of wood, drill 27 5mm holes, insert LEDs, use a Dymo labeler for numbers, wire to a PIC. This project shows how to connect up to 30 LEDs using only six I/O pins.
The DymoClock is a 12-hour clock with 27 LEDs and a 2C resolution thermometer, all driven by a single PIC16F819 microcontroller.
Circuit Schematic
Built around the 18-pin PIC16F819. The LED driving technique comes from Microchip Application Note AN234, using 25 mA LEDs without current limiting resistors. A silicon diode serves as the temperature sensor.
Display Modes
The DymoClock has three display modes:
- Hours:Minutes — displays the current time
- Seconds — displays the seconds count
- Temperature — displays the ambient temperature
The MODE button cycles between the three display modes. The TOGGLE button enables auto-switching between modes. Pressing both buttons simultaneously enters time-setting mode.
C Source Code
dymoclock.c
/*
* file : dymoclock.c
* project : Simple LED clock with thermometer
* compiler : mikroC V6.0.0.0
* date : september 15, 2006
*
* description :
* 12 hours clock with 27 LEDs display, 2C resolution thermometer
*
* target device :
* PIC16F819 with 16 Mhz crystal
*
* configuration bits :
* HS clock, no watchdog, RA5 as MCLR,
* brown out detect, LVP disabled, CCP1 on RB2
*
*******************************************************************************
*/
/*
* display modes
*/
#define MODE_HOURMN 0 // hours:minutes
#define MODE_SS 1 // seconds
#define MODE_TEMP 2 // temperature
#define MAX_MODE 3
/*
* buttons
*/
#define BUTTON ((PORTA.F1 == 0) || (PORTA.F2 == 0))
#define BUTTON_MODE (PORTA.F1 == 0)
#define BUTTON_TOGGLE (PORTA.F2 == 0)
#define BUTTON_SET ((PORTA.F1 == 0) && (PORTA.F2 == 0))
#define TEMP_REF 115 // silicon junction offset: 600 mV
#define MAX_TEMP 20 // number of temperature samples
/*
* LED multiplexing tables
*/
const unsigned char hhTable[] = { 0, 1, 2, 3, 4, 7, 8, 13, 14, 5, 6, 9, 10 } ;
const unsigned char mnTableH[] =
{
0, 0, 0, 0, 0,
15, 15, 15, 15, 15,
16, 16, 16, 16, 16,
23, 23, 23, 23, 23,
24, 24, 24, 24, 24,
11, 11, 11, 11, 11,
12, 12, 12, 12, 12,
17, 17, 17, 17, 17,
18, 18, 18, 18, 18,
19, 19, 19, 19, 19,
20, 20, 20, 20, 20,
27, 27, 27, 27, 27
} ;
const unsigned char mnTableL[] =
{
0, 22, 21, 25, 26,
0, 22, 21, 25, 26,
0, 22, 21, 25, 26,
0, 22, 21, 25, 26,
0, 22, 21, 25, 26,
0, 22, 21, 25, 26,
0, 22, 21, 25, 26,
0, 22, 21, 25, 26,
0, 22, 21, 25, 26,
0, 22, 21, 25, 26,
0, 22, 21, 25, 26,
0, 22, 21, 25, 26
} ;
unsigned char mode ;
unsigned char toggleMode ;
unsigned int scaler = 0 ;
unsigned char hh = 1 ;
unsigned char mn = 1 ;
unsigned char ss = 0 ;
int temp ;
unsigned char tdeg[MAX_TEMP] ;
unsigned char tidx = 0 ;
/*
* ISR: called Fosc / 4 / 256 times per second
*/
void interrupt(void)
{
if(INTCON.TMR0IF)
{
scaler++ ;
if(scaler == 15625)
{
scaler = 0 ;
ss++ ;
if(ss == 60)
{
ss = 0 ;
mn++ ;
if(mn == 60)
{
mn = 0 ;
hh++ ;
if(hh == 13)
{
hh = 1 ;
}
}
}
}
INTCON.TMR0IF = 0 ;
}
}
/*
* light LED number n during d milliseconds
*/
void dymoLight(const unsigned char n, unsigned char d)
{
switch(n)
{
case 0 : TRISB = 0b11111111 ; PORTB = 0b00000000 ; break ;
case 1 : TRISB = 0b11111100 ; PORTB = 0b00000001 ; break ;
case 2 : TRISB = 0b11111100 ; PORTB = 0b00000010 ; break ;
case 3 : TRISB = 0b11111010 ; PORTB = 0b00000001 ; break ;
case 4 : TRISB = 0b11111010 ; PORTB = 0b00000100 ; break ;
case 5 : TRISB = 0b11111001 ; PORTB = 0b00000010 ; break ;
case 6 : TRISB = 0b11111001 ; PORTB = 0b00000100 ; break ;
case 7 : TRISB = 0b11110110 ; PORTB = 0b00000001 ; break ;
case 8 : TRISB = 0b11110110 ; PORTB = 0b00001000 ; break ;
case 9 : TRISB = 0b11110101 ; PORTB = 0b00000010 ; break ;
case 10 : TRISB = 0b11110101 ; PORTB = 0b00001000 ; break ;
case 11 : TRISB = 0b11110011 ; PORTB = 0b00000100 ; break ;
case 12 : TRISB = 0b11110011 ; PORTB = 0b00001000 ; break ;
case 13 : TRISB = 0b11101110 ; PORTB = 0b00000001 ; break ;
case 14 : TRISB = 0b11101110 ; PORTB = 0b00010000 ; break ;
case 15 : TRISB = 0b11101101 ; PORTB = 0b00000010 ; break ;
case 16 : TRISB = 0b11101101 ; PORTB = 0b00010000 ; break ;
case 17 : TRISB = 0b11101011 ; PORTB = 0b00000100 ; break ;
case 18 : TRISB = 0b11101011 ; PORTB = 0b00010000 ; break ;
case 19 : TRISB = 0b11100111 ; PORTB = 0b00001000 ; break ;
case 20 : TRISB = 0b11100111 ; PORTB = 0b00010000 ; break ;
case 21 : TRISB = 0b11011110 ; PORTB = 0b00000001 ; break ;
case 22 : TRISB = 0b11011110 ; PORTB = 0b00100000 ; break ;
case 23 : TRISB = 0b11011101 ; PORTB = 0b00000010 ; break ;
case 24 : TRISB = 0b11011101 ; PORTB = 0b00100000 ; break ;
case 25 : TRISB = 0b11011011 ; PORTB = 0b00000100 ; break ;
case 26 : TRISB = 0b11011011 ; PORTB = 0b00100000 ; break ;
case 27 : TRISB = 0b11010111 ; PORTB = 0b00001000 ; break ;
case 28 : TRISB = 0b11010111 ; PORTB = 0b00100000 ; break ;
case 29 : TRISB = 0b11001111 ; PORTB = 0b00010000 ; break ;
case 30 : TRISB = 0b11001111 ; PORTB = 0b00100000 ; break ;
}
VDelay_ms(d) ;
}
/*
* set clock time
*/
void setTime()
{
INTCON.GIE = 0 ;
hh = 1 ;
for(;;)
{
dymoLight(hhTable[hh], 20) ;
if(BUTTON_MODE)
{
VDelay_ms(15) ;
while(BUTTON_MODE) ;
VDelay_ms(15) ;
hh++ ;
if(hh > 12) { hh = 1 ; }
}
if(BUTTON_TOGGLE)
{
VDelay_ms(15) ;
while(BUTTON_TOGGLE) ;
VDelay_ms(15) ;
break ;
}
}
mn = 1 ;
for(;;)
{
dymoLight(mnTableH[mn], 10) ;
dymoLight(mnTableL[mn], 10) ;
if(BUTTON_MODE)
{
VDelay_ms(15) ;
while(BUTTON_MODE) ;
VDelay_ms(15) ;
mn++ ;
if(mn > 59) { mn = 0 ; }
}
if(BUTTON_TOGGLE)
{
VDelay_ms(15) ;
while(BUTTON_TOGGLE) ;
VDelay_ms(15) ;
break ;
}
}
ss = 0 ;
INTCON.GIE = 1 ;
toggleMode = 0 ;
mode = MODE_HOURMN ;
}
/*
* main entry
*/
void main()
{
unsigned int loopCtr = 0 ;
unsigned int toggleCtr = 0 ;
ADCON1 = 0b00001110 ; // RA0 analog, others digital
TRISA = 0b11111111 ;
PORTA = 0 ;
TRISB = 0xff ; // display off
INTCON.TMR0IF = 0 ;
INTCON.TMR0IE = 1 ;
OPTION_REG.T0CS = 0 ;
OPTION_REG.PS2 = 0 ;
OPTION_REG.PS1 = 0 ;
OPTION_REG.PS0 = 0 ;
OPTION_REG.PSA = 1 ; // no prescaler
setTime() ;
for(;;)
{
loopCtr++ ;
toggleCtr++ ;
if(BUTTON)
{
unsigned char b = 0 ;
VDelay_ms(15) ;
while(BUTTON)
{
if(BUTTON_SET)
{
dymoLight(hhTable[0], 1) ;
dymoLight(mnTableH[0], 1) ;
dymoLight(mnTableL[0], 1) ;
VDelay_ms(1000) ;
setTime() ;
break ;
}
else if(BUTTON_MODE) { b = 1 ; }
else if(BUTTON_TOGGLE) { b = 2 ; }
VDelay_ms(15) ;
}
if(b == 1)
{
VDelay_ms(15) ;
while(BUTTON_MODE) ;
VDelay_ms(15) ;
mode++ ;
toggleMode = 0 ;
if(mode == MAX_MODE) { mode = 0 ; }
}
else if(b == 2)
{
VDelay_ms(15) ;
while(BUTTON_TOGGLE) ;
VDelay_ms(15) ;
toggleMode = !toggleMode ;
}
}
if(mode == MODE_HOURMN)
{
dymoLight(hhTable[hh], 5) ;
dymoLight(mnTableH[mn], 5) ;
dymoLight(mnTableL[mn], 5) ;
if(toggleMode && (toggleCtr > 400))
{ toggleCtr = 0 ; mode = MODE_TEMP ; }
}
else if(mode == MODE_SS)
{
dymoLight(mnTableH[ss], 5) ;
dymoLight(mnTableL[ss], 5) ;
}
else if(mode == MODE_TEMP)
{
unsigned char i ;
if(loopCtr > 20)
{
loopCtr = 0 ;
temp = TEMP_REF - Adc_Read(0) ;
temp *= 221 ;
temp /= 102 ;
temp = 25 + temp ;
tdeg[tidx] = temp ;
tidx++ ;
if(tidx == MAX_TEMP) { tidx = 0 ; }
temp = 0 ;
for(i = 0 ; i < MAX_TEMP ; i++)
{ temp += tdeg[i] ; }
temp /= MAX_TEMP ;
}
if((temp > 0) && (temp < 60))
{
dymoLight(mnTableL[temp], 5) ;
dymoLight(mnTableH[temp], 5) ;
}
if(toggleMode && (toggleCtr > 200))
{ toggleCtr = 0 ; mode = MODE_HOURMN ; }
}
}
}
Note
No separate project ZIP file was provided for this project. The source code above is the complete mikroC program — copy and paste it into your mikroC IDE to build the project.
User Builds
The DymoClock project inspired several community builds and variations:
Lubo_plan's DymoClock
A faithful reproduction of the original design:
Gerard's Binary Clock
A creative twist using a blue-white-red binary display format:
