[SOLVED] designing an alarm clock circuit

[tapu]

Dear all
I am designing just alarm clock with89c52.I want to clear doubts following.
1)Can alarm signal from controller directly conect to 12v relay circuit?as i am controlling ac circuit like electric bell.
2)I connect keypad directly to port2.is it ok?or i have to connect through pullups?

 

[milan.rajik]

You need a BJT or FET to drive the Relay.
You need either puul ups or pull downs to avoid pins from entering floating state.

 

[tapu]

Dear milan.rajik, Which type of Relay is suitable for switching electric bell of 230v ac.

 

[Debasis Swain]

Remember one thing you can't directly operate the relay from the mcu. So, you have need a switching ckt to operate that relay like +12v SPDT .
The switching ckt like you can use Bc547 or ULN2803 etc and the keypad is better if you add pull up to it.

 

[milan.rajik]

You need to use a transistor like BC337 to drive the relay. Relay can be 12V DC coil and 240V AC 2Amp type to drive the bell. You need to put a 100 nF Multilayer Ceramic and 1N4007 in parallel with Relay Coil.

 

[tapu]

Dear sir
Thank you for clearing doubts in above posts.
I have writen code in 89c52 to 4078 kbytes.Program running successfully.but further I added code for more alarms (becouse I want to make multievent alarm clock)then program does not executed in actual board.Please reply.

 

[tapu]

Dear all,
The above problom have solved by using new chip.I am using relay for controlling electric bell in alarm clock project.
But when high signal gone to relay circuit from 89s52 then relay does not energised & observed 0.27v at that pin.(as relay disconnected then proper 5v observed).Here I uploaded a part of schematic of relay circuit.Please Reply.

 

[milan.rajik]

Relay circuit is fine. You can replace 4.7k with 1k if needed. Zip and post code.

 

[tapu]

Thank you for replying milan.rajik.i think their is no any problom in code becouse when Relay circuit is disconnected that pin shows hi or low signal according to code.one thing when I connect pullup to that pin then relay energised.. is it right to connect pullup?

 

[tapu]

dear sir should I connect microcontroller's pin(signal) to relay through pullups resistor for switching electric bell?

 

[milan.rajik]

No, you should not use pullups for transistor circuit driving the relay. I mentioned pullups for keypad circuit.

 

[tapu]

As Relay circuit is OK.Then it shoud energised.Is their any IC connected in betwen relay & controller?
Here I take signal from P1.4 of microcontroller.

 

[tapu]

Dear all,
the above probloms have been solved.one thing i want to know if all the pins & ports of 89c52 have used & still i want some pins then what should i do?

 

[arun_190175]

for relay and led (only for output) you can ues shiftreg. 74hc595 or any ,also you can use i2c port expender.

 

[tapu]

Dear All
thank you for replies.I have been completed my project.but one problom, I am using ds1307 Rtc with crystel 32.768khz crystel for clock.I observed RTC running 5 minute back per day in clock.that means accuracy of a rtc is not good.How to solve this type of problom.Please reply.

 

[aameer]

Dear Tapu can u post the code and circuit of your project done

 

[tapu]

Thank you for reply aameer.Here is a circuit & code.http:
View attachment CLK.JPG

		#include<reg51.h>
sbit e1=P2^6;
sbit e2=P2^7;
sbit e3=P2^3;
sbit led=P2^2;

sbit e4=P1^5;
sbit e5=P1^7;
sbit e6=P1^6;
sbit e7=P3^4;


sbit e8=P2^0;
sbit e9=P2^1;

sbit e10=P0^6;
sbit e11=P0^7;
sbit e12=P0^5;

sbit set=P1^0;
sbit mov=P1^1;
sbit inc=P1^2;
sbit dec=P1^3;
sbit ent=P1^4;
sbit alarmset=P3^7;
bit c;
bit d;
bit e;
void all_disp();
void time_set();
 alarm_chk();
 alarm_chk1();
 alarm_chk2();
 alarm_chk3();
 alarm_chk4();
 alarm_chk5();
 alarm_chk6();
 alarm_chk7();
 
void alarm_set();



sbit sda_rtc =P2^5;
sbit scl_rtc =P2^4;


void Delay(unsigned int);
void del();
void msdelay(unsigned int value);
void alarm_bel();
void display_alarmd1(unsigned char value);
void display_alarmd2(unsigned char value);


#define DS1307_ID 0xD0
#define SEC 0x00
#define MIN 0x01
#define HOUR 0x02
#define DATE 0x04
#define MONTH 0x05
#define YEAR 0x06



DS1307_get(unsigned char);
void DS1307_settime(unsigned char, unsigned char, unsigned char);
void DS1307_setdate(unsigned char, unsigned char, unsigned char);
Send2lcd(unsigned char);
void Seg8_decimal2(min);

void Led8decimal2(hour);

void Rtc_Write(unsigned char,unsigned char);
Rtc_Read(unsigned char);
void Rtc_rd_wr_sub();
void Rtc_Init();
void Rtc_Start();
void Rtc_Tx();
void Rtc_Rx();
void Rtc_Stop();
void Rtc_Ack();


unsigned int Rtc_add_wr,Rtc_add_rd;
unsigned char d_rtc,datain_rtc,in_rtc,temp_rtc,dat_rtc,flag_rtc;

unsigned char i,j,a[10],cur=0;
unsigned char sec,hour,min,date,month,year,sec1,hour1,min1,sec2, hour2,min2,event,hh,mm,ss,dd,mn,yy,asec,amin,ahour,asec1,amin1,ahour1,asec2,amin2,ahour2,asec3,amin3,ahour3,asec4,amin4,ahour4,asec5,amin5,ahour5,asec6,amin6,ahour6,asec7,amin7,ahour7;
unsigned char count[13]={0x86,0x89,0x8c,0xc6,0xc9,0xcc,0x80,0x81,0x82,0x83,0x84,0x85,0x86};

unsigned char dec_hex(unsigned char tt)
{
if(tt>59)
tt+=36;

else if(tt>49)
tt+=30;
else if(tt>39)
tt+=24;
else if(tt>29)
tt+=18;
else if(tt>19)
tt+=12;
else if(tt>9)
tt+=6;
return(tt);
} 

void all_disp()
{
sec = DS1307_get(SEC);
min = DS1307_get(MIN);
hour = DS1307_get(HOUR);

min=Send2lcd(min);
hour=Send2lcd(hour);

Seg8_decimal2(min);
Led8decimal2(hour);


}
void main()
{
Delay(65000);
Delay(65000);
Rtc_Init();

//DS1307_setdate(0x04,0x11,0x11);
//DS1307_settime(0x16,0x00,0x00);

while(1)
{
all_disp();
alarm_chk();
alarm_chk1();
alarm_chk2();
alarm_chk3();
alarm_chk4();
alarm_chk5();
alarm_chk6();
alarm_chk7();

if(!set)
time_set();
if(alarmset==1)
alarm_set();
}
}


void time_set()
{
Delay(65000);
all_disp();
cur=3;
while(ent)
{
if(mov==0)
{
while(!mov);
cur++;
if(cur==6)
cur=3;
}
else if(count[cur]==0x86)
{
if(inc==0)
{
while(!inc);
date++;
if(date>=32)
date=1;
}
else if(dec==0)
{
while(!dec);
date--;
if(date==0xff)
date=31;
}
}

else if(count[cur]==0x89)
{
if(inc==0)
{
while(!inc);
month++;
if(month>=13)
month=1;
}
else if(dec==0)
{
while(!dec);
month--;
if(month==0xff)
month=12;
}
}

else if(count[cur]==0x8c)
{
if(inc==0)
{
while(!inc);
year++;
if(year>99)
year=0;
}
else if(dec==0)
{
while(!dec);
year--;
if(year==0xff)
year=99;
}
}

else if(count[cur]==0xc6)
{
if(inc==0)
{
while(inc==0);
hour++;
Led8decimal2(hour);

if(hour>=24)
hour=0;
}
else if(dec==0)
{
while(dec==0);
hour--;
Led8decimal2(hour);

if(hour==0)
hour=23;
}
}

else if(count[cur]==0xc9)
{
if(inc==0)
{
while(inc==0);
min++;
Seg8_decimal2(min);

if(min>=60)
min=0;
}
else if(dec==0)
{
while(dec==0);
min--;
Seg8_decimal2(min);

if(min==0)
min=59;
}
}

else if(count[cur]==0xcc)
{
if(inc==0)
{
while(inc==0);
sec++;

if(sec>=60)
sec=0;
}
else if(dec==0)
{
while(dec==0);
sec--;

if(sec==0xff)
sec=59;
}
}
}


Delay(65000);Delay(65000);

dd=dec_hex(date);
mn=dec_hex(month);
yy=dec_hex(year);
hh=dec_hex(hour);
mm=dec_hex(min);
ss=dec_hex(sec);

DS1307_settime(hh,mm,ss);
DS1307_setdate(dd,mn,yy); 
Delay(65000);
}








void Seg8_decimal2(min)

{
unsigned int Lcd_hr,Lcd_t,Lcd_o;

Lcd_hr=min%100;
Lcd_t=Lcd_hr/10;
Lcd_o=Lcd_hr%10;
e4=0;
P3=Lcd_t+0x30;
e4=1;
e3=0;
P3=Lcd_o+0x30;
e3=1;

}







void Led8decimal2(hour)
{
unsigned int Lcd_hr,Lcd_t,Lcd_o;

Lcd_hr=hour%100;
Lcd_t=Lcd_hr/10;
Lcd_o=Lcd_hr%10;
e5=0;
P3=Lcd_t+0x30;
e5=1;
e6=0;
P3=Lcd_o+0x30;
e6=1;

}






void Delay(unsigned int del)
{
while(del--);
}

void del()
{
Delay(65000);
Delay(65000);
}
void alarm_set()
	
{
	cur=7;
	event=0x01;
	e12=0;                                 //ALARM1
	P0=event;
		e12=1;

while(ent)
{
if(mov==0)
{
while(!mov);
cur++;
if(cur==13)
cur=7;
}
else if(count[cur]==0x82)
{
if(inc==0)
{
while(!inc);
amin++;
Send2lcd(amin);
display_alarmd1(amin);


}
else if(dec==0)
{
while(!dec);
amin--;
}
}

else if(count[cur]==0x81)
{
if(inc==0)
{
while(!inc);
ahour++;
	Send2lcd(ahour);
display_alarmd2(ahour);

}
else if(dec==0)
{
while(!dec);
ahour--;
}
}

else if(count[cur]==0x83)
	
{
		event=0x02;
	e12=0;
	P0=event;                                     //ALARM2
		e12=1;
Send2lcd(amin1);
display_alarmd1(amin1);
Send2lcd(ahour1);
display_alarmd2(ahour1);


if(inc==0)
{
while(!inc);
amin1++;
Send2lcd(amin1);
display_alarmd1(amin1);


}
else if(dec==0)
{
while(!dec);
amin1--;
}
}

else if(count[cur]==0x84)
{
if(inc==0)
{
while(!inc);
ahour1++;
	Send2lcd(ahour1);
display_alarmd2(ahour1);

}
else if(dec==0)
{
while(!dec);
ahour1--;
}
}
else if(count[cur]==0x85)
	
{
		event=0x03;
	e12=0;
	P0=event;                                     //ALARM3
		e12=1;
Send2lcd(amin2);
display_alarmd1(amin2);
Send2lcd(ahour2);
display_alarmd2(ahour2);


if(inc==0)
{
while(!inc);
amin2++;
Send2lcd(amin2);
display_alarmd1(amin2);


}
else if(dec==0)
{
while(!dec);
amin2--;
}
}

else if(count[cur]==0x86)
{
if(inc==0)
{
while(!inc);
ahour2++;
	Send2lcd(ahour2);
display_alarmd2(ahour2);

}
else if(dec==0)
{
while(!dec);
ahour2--;
}
}

}
}

	
	
	
	
	

Send2lcd(unsigned char value)
{
unsigned char buf1,buf2,buf = 0;

buf1 = value & 0xF0; /* Filter for high byte */
buf1 = (buf1>>4); /* Convert to ascii code */
buf2 = value & 0x0F; /* Filter for low byte */

buf=(buf1*10)+buf2;
return buf;
}

void display_alarmd1(unsigned char value)
{
unsigned int Lcd_hr,Lcd_t,Lcd_o;

Lcd_hr=value%100;
Lcd_t=Lcd_hr/10;
Lcd_o=Lcd_hr%10;
e9=0;
P0=Lcd_t+0x30;
e9=1;
e8=0;
P0=Lcd_o+0x30;
e8=1;

}
void display_alarmd2(unsigned char value)
{
unsigned int Lcd_hr,Lcd_t,Lcd_o;

Lcd_hr=value%100;
Lcd_t=Lcd_hr/10;
Lcd_o=Lcd_hr%10;
e10=0;
P0=Lcd_t+0x30;
e10=1;
e11=0;
P0=Lcd_o+0x30;
e11=1;

}








void msdelay(unsigned int value)
{
	unsigned int x,y;
	for(x=0;x<1275;x++)
	for(y=0;y<value;y++);
}
alarm_chk()
{
asec=0;																																																																				

if(min==amin)
c=1;
else
	c=0;

if(hour==ahour)
d=1;
else
	d=0;
if(sec==asec)
e=1;
else
e=0;	
if(c==1)
if(d==1)
if(e==1)	
alarm_bel();

else

led=1;	
return 0;	
}

alarm_chk1()
{
asec1=0;																																																																				

if(min==amin1)
c=1;
else
	c=0;

if(hour==ahour1)
d=1;
else
	d=0;
if(sec==asec1)
e=1;
else
e=0;	
if(c==1)
if(d==1)
if(e==1)	
alarm_bel();

else

led=1;	
return 0;	
}

alarm_chk2()
{
asec2=0;																																																																				

if(min==amin2)
c=1;
else
	c=0;

if(hour==ahour2)
d=1;
else
	d=0;
if(sec==asec2)
e=1;
else
e=0;	
if(c==1)
if(d==1)
if(e==1)	
alarm_bel();

else

led=1;	
return 0;	
}

alarm_chk3()
{
asec3=0;																																																																				

if(min==amin3)
c=1;
else
	c=0;

if(hour==ahour3)
d=1;
else
	d=0;
if(sec==asec3)
e=1;
else
e=0;	
if(c==1)
if(d==1)
if(e==1)	
alarm_bel();

else

led=1;	
return 0;	
}

alarm_chk4()
{
asec=0;																																																																				

if(min==amin4)
c=1;
else
	c=0;

if(hour==ahour4)
d=1;
else
	d=0;
if(sec==asec4)
e=1;
else
e=0;	
if(c==1)
if(d==1)
if(e==1)	
alarm_bel();

else

led=1;	
return 0;	
}

alarm_chk5()
{
asec5=0;																																																																				

if(min==amin5)
c=1;
else
	c=0;

if(hour==ahour5)
d=1;
else
	d=0;
if(sec==asec5)
e=1;
else
e=0;	
if(c==1)
if(d==1)
if(e==1)	
alarm_bel();

else

led=1;	
return 0;	
}

alarm_chk6()
{
asec6=0;																																																																				

if(min==amin6)
c=1;
else
	c=0;

if(hour==ahour6)
d=1;
else
	d=0;
if(sec==asec6)
e=1;
else
e=0;	
if(c==1)
if(d==1)
if(e==1)	
alarm_bel();

else

led=1;	
return 0;	
}

alarm_chk7()
{
asec=0;																																																																				

if(min==amin7)
c=1;
else
	c=0;

if(hour==ahour7)
d=1;
else
	d=0;
if(sec==asec7)
e=1;
else
e=0;	
if(c==1)
if(d==1)
if(e==1)	
alarm_bel();

else

led=1;	
return 0;	
}







void alarm_bel()
{
led=0;
msdelay(150);
led=1;
}	






/*********************************LCD HEADER FILE END*************************************/



/*********************************RTC HEADER FILE START*********************************/


DS1307_get(unsigned char addr)
{
unsigned char ret;


Rtc_Start(); 
ret = Rtc_Read(addr);
Rtc_Stop();

return ret;
}

void DS1307_settime(unsigned char hh, unsigned char mm, unsigned char ss)
{
Rtc_Start(); 

Rtc_Write(0x00,ss); /* Write sec on RAM address 00H */
Rtc_Write(0x01,mm); /* Write min on RAM address 01H */
Rtc_Write(0x02,hh); /* Write hour on RAM address 02H */

Rtc_Stop(); /* Stop i2c bus */
}


void DS1307_setdate(unsigned char dd, unsigned char mm, unsigned char yy)
{
Rtc_Start();

Rtc_Write(0x04,dd); /* Write date on RAM address 04H */
Rtc_Write(0x05,mm); /* Write month on RAM address 05H */
Rtc_Write(0x06,yy); /* Write year on RAM address 06H */

Rtc_Stop(); /* Stop i2c bus */
}


Send2lcd_alarm(unsigned char value)
{
unsigned char buf1,buf2,buf = 0;

buf1 = value & 0xF0; /* Filter for high byte */
buf1 = (buf1>>4); /* Convert to ascii code */
buf2 = value & 0x0F; /* Filter for low byte */
buf=(buf1*10)+buf2;

return buf;
}




void Rtc_Init()//lower order 256 bytes of the chip
{
Rtc_add_wr=0xd0;
Rtc_add_rd=0xd1;
}



void Rtc_Write(unsigned char zig,unsigned char zag)// program to write to EEPROM
{
dat_rtc=zig;
temp_rtc=zag;
Rtc_rd_wr_sub();
above:
d_rtc=temp_rtc;
Rtc_Tx();
if (CY==1)goto above;
CY=0;
Rtc_Stop();
}


Rtc_Read(unsigned char zig)// program to read from EEPROM
{
dat_rtc=zig;
Rtc_rd_wr_sub();
Rtc_Start();
be:
d_rtc=Rtc_add_rd; // 0xd1 =Rtc_add_rd
Rtc_Tx();
if(CY==1)goto be;
Rtc_Rx();
Rtc_Ack();
CY=0;
Rtc_Stop();
return(datain_rtc);
}


void Rtc_Start()// must for any operation on EEPROM
{
sda_rtc=1;
scl_rtc=1;
sda_rtc=0;
scl_rtc=0;
}


void Rtc_Stop()// this is similar to the START operation whereas this should be performed after the completion of any operation
{
sda_rtc=0;
scl_rtc=1;
sda_rtc=1;
}


void Rtc_Tx()// program to send the device address, read/write address,data to be written
{
signed char i_rtc;
for(i_rtc=7;i_rtc>=0;i_rtc--)// should necessarily be initialised as signed char.
{
CY=(d_rtc>>i_rtc)&0x01;
sda_rtc=CY;
scl_rtc=1;// clock is essential inorder to write or read
scl_rtc=0;// clk should be alternated
}
sda_rtc=1;
scl_rtc=1;
CY=sda_rtc;
scl_rtc=0;
}


void Rtc_Rx()// program read the data from the EEPROM
{
unsigned char l_rtc;
sda_rtc=1;
for (l_rtc=0;l_rtc<=7;l_rtc++)
{
scl_rtc=1;
in_rtc=in_rtc<<1;
in_rtc|=sda_rtc;
scl_rtc=0;
}
datain_rtc=in_rtc;
in_rtc=0;
}


void Rtc_Ack()// this is to intimate the EEPROM that the read operation is over
{
sda_rtc=1;
scl_rtc=1;
scl_rtc=0;
}


void Rtc_rd_wr_sub()// this routine will be used by both the read & write operations to send the device address & the address at which the corresponding action is to be taken
{
Rtc_Start();
here1:
d_rtc=Rtc_add_wr;// 0xd0 device address is passed
Rtc_Tx();
if(CY==1)goto here1;
again1:
d_rtc=dat_rtc;// the address from which data is to be read/written is to be passed
Rtc_Tx();
if(CY==1)goto again1;
}

 

[arun_190175]

please check rtc crystal issue check cap.load on 32.68khz read data sheet DS1307 according datasheet 8pf is recomended for input and output load if you use bigger then recomemded running slow else if you use less
rtc running fast so check this

 

[aameer]

i cant view your circuit.

 

[tapu]

If above circuit can't open then try this

**broken link removed**