problem with arduino

[marrc]

hi guys!

I have recently put together a device that can measure and display temperature.

i am using 2 seven segment displays, one small display for displaying some parameters and 1 large display (4inch height) for displaying the temperature.

now the problem with the large display is that the right most digit is extra bright while the left three are very dim.

i am pretty sure its not a wiring issue or hardware problem as i have run a test code that displays all 4 digits with equal brightness on same display.

please help me so that all 4 digits of large display are equally bright.

P.S:I am a newbe to arduino so forgive me if my code is a bit messy.

cheers,
marrc

my code is as follows:

#include <adafruit_max31856.h> // inclusion of temperature module library
int latchPin1=2;  //for small display
int dataPin1=3;
int clockPin1=4;
int D5=5,D6=6,c=0,switchState,dig,dig_1,dig_2,dig_3,dig_4;
float c1;
int initialstateD5,finalstateD5,initialstateD6,finalstateD6;
int latchPin=7;  //for large display
int dataPin=8;
int clockPin=9;
int temp_sens, temp_read, temp_hyst, dig_5, dig_6, dig_7, dig_8;
//temp_sens=temperature reading of thermocouple, temp_read=temperature on the display, temp_hyst=plateau hysteresis teperature (variable),
//dig_1, dig_2, dig_3, dig_4 = displayed digits from left to right
int dev_pc = 0; // plateau temperature deviation margin percentage (+/- %)
int temp_seek = 400; // temp_seek=tmeperature when plateau detection is initiated
float time_hyst = c1;//=1.8; // plateau wait time (s)
int temp_offset=c; // this value will be subtracted from the actual reading with proper -/+ sign
unsigned long time_res; // time_res=plateau reset time (variable) (ms)
int refresh = 1; // refresh= display hold time (ms)
Adafruit_MAX31856 max = Adafruit_MAX31856(10, 11, 12, 13); // CS, SDI, SDO, SCK pins on the module

void setup()
{
 
  max.begin(); // temperature module initiation
  max.setThermocoupleType(MAX31856_TCTYPE_S); // thermocouple type selection
  pinMode(A3, INPUT_PULLUP); // enabling internal pullup resistance on the Arduino
  pinMode(A5, OUTPUT);
  pinMode (latchPin,OUTPUT);
  pinMode (dataPin,OUTPUT);
  pinMode (clockPin,OUTPUT);
  Serial.begin(9600);
  pinMode (latchPin1,OUTPUT);
pinMode (dataPin1,OUTPUT);
pinMode (clockPin1,OUTPUT);
pinMode (D5,INPUT);  //increment pin
pinMode (D6,INPUT);  // decrement pin
pinMode (A4,INPUT);  //counter select
}

void loop()
{
  switchState= digitalRead(A4);
  if(switchState==LOW) // whole number counter if a4 low
  {
  // put your main code here, to run repeatedly:
  finalstateD5=digitalRead(D5);
  if(finalstateD5 != initialstateD5)
   {
  delay(1);
  finalstateD5=digitalRead(D5);
  if (finalstateD5==HIGH)
  c++;
  Serial.println(c);
  initialstateD5=finalstateD5;
   }
   
dig_1 = c/1000;
dig_2 = (c - 1000 * dig_1) / 100;                     
dig_3 = (c - 1000 * dig_1 - 100 * dig_2) / 10;    
dig_4 = c - 1000 * dig_1 - 100 * dig_2 - 10 * dig_3; 
displayDigit();  //displays offset

  finalstateD6=digitalRead(D6);
  if(finalstateD6 != initialstateD6 )
   {
  delay(1);
  finalstateD6=digitalRead(D6);
  if (finalstateD6==HIGH)
  c--;
  initialstateD6=finalstateD6;
   }
   
dig_1 = c/1000;
dig_2 = (c - 1000 * dig_1) / 100;                    
dig_3 = (c - 1000 * dig_1 - 100 * dig_2) / 10;    
dig_4 = c - 1000 * dig_1 - 100 * dig_2 - 10 * dig_3; 
displayDigit();
  }
  else
  if (switchState=HIGH) // decimal counter if a4 high
  {
  finalstateD5=digitalRead(D5);
  if(finalstateD5 != initialstateD5)
   {
  delay(1);
  finalstateD5=digitalRead(D5);
  if (finalstateD5==HIGH)
  c1=c1+0.01;
  Serial.println(c1);
 
  initialstateD5=finalstateD5;
   }
   
dig_1 = c1*100/1000;
dig_2 = (c1*100 - 1000 * dig_1) / 100;                    
dig_3 = (c1*100 - 1000 * dig_1 - 100 * dig_2) / 10;   
dig_4 = c1*100 - 1000 * dig_1 - 100 * dig_2 - 10 * dig_3; 
displayDigit1(); //displays plateau time

  finalstateD6=digitalRead(D6);
  if(finalstateD6 != initialstateD6 )
   {
  delay(1);
  finalstateD6=digitalRead(D6);
  if (finalstateD6==HIGH)
  c1=c1-0.01;
  initialstateD6=finalstateD6;
   }
   
dig_1 = c1*100/1000;
dig_2 = (c1*100 - 1000 * dig_1) / 100;                    
dig_3 = (c1*100 - 1000 * dig_1 - 100 * dig_2) / 10;   
dig_4 = c1*100 - 1000 * dig_1 - 100 * dig_2 - 10 * dig_3; 
displayDigit1();
  }
 
  {
    Serial.println("OK");
    digitalWrite(A2, HIGH); // green LED on
   if(digitalRead(A3)==HIGH) // checking if digital pin 17 is high (high if Red LED is off)
  temp_sens = max.readThermocoupleTemperature(); // max.readThermocoupleTemperature()=temperature from module (updated if the condition is met)
  else                                // checking if digital pin 17 is high (low if Red LED is on)
  temp_sens != max.readThermocoupleTemperature(); // max.readThermocoupleTemperature()=temperature from module (not updated if the condition is not met)
  if (temp_sens <= temp_seek) // checking if temperaure is lower than plateau initiation temperature
  {
    digitalWrite(A0, LOW); // red LED off
    digitalWrite(A1, LOW); // amber LED off
    digitalWrite(A2, HIGH); // green LED on, indicating current temperature is lower than temp_seek
  }
  else
  {
    digitalWrite(A0, LOW); // red LED off
    digitalWrite(A1, HIGH); // amber LED on, indicating plateau detection is active
    digitalWrite(A2, LOW); // green LED off

    if (temp_sens <= (100 + dev_pc) * temp_hyst / 100 && temp_sens >= (100 - dev_pc) * temp_hyst / 100) // checking if the temperature within the platuea's range
    {
      if (millis() > 1000 * c1) // checking if the waiting time has elapsed
      {
        digitalWrite(A0, HIGH); // red LED on, indicating a plateau is detected
        digitalWrite(A1, LOW); // amber LED off
        digitalWrite(A2, LOW); // green LED off
        digitalWrite(A5, HIGH); // for red relay
      }
    }
    else
    {
      time_res = millis(); // redefining the value of wait time for further iterations
      digitalWrite(A0, LOW); // red LED off
    digitalWrite(A1, HIGH); // amber LED on, indicating plateau detection is active
    digitalWrite(A2, LOW); // green LED off
      temp_hyst = temp_sens; // redefining the value of hysteresis temperature for further iterations
    }
  }
  temp_read = temp_sens-c;
  if (temp_read < 0)
    temp_read = 0;
  if (temp_read > 9999)
    temp_read = 9999;
  dig_5 = temp_read / 1000;                                     // digit 1 temperature value
  dig_6 = (temp_read - 1000 * dig_5) / 100;                     // digit 2 temperature value
  dig_7 = (temp_read - 1000 * dig_5 - 100 * dig_6) / 10;        // digit 3 temperature value
  dig_8 = temp_read - 1000 * dig_5 - 100 * dig_6 - 10 * dig_7;  // digit 4 temperature value
  }
  Serial.println(dig_6);
getDigit1(dig_5);  // gets digits for large display
digitalWrite(latchPin,LOW);
shiftOut(dataPin,clockPin,MSBFIRST,128+63 >> 8);// shifting out zeros
shiftOut(dataPin,clockPin,MSBFIRST,128+dig);// displaying digit
digitalWrite(latchPin,HIGH);
delay(1);
getDigit1(dig_6);
Serial.println(dig);
digitalWrite(latchPin,LOW);
shiftOut(dataPin,clockPin,MSBFIRST,256+63 >> 8);
shiftOut(dataPin,clockPin,MSBFIRST,256+dig);
digitalWrite(latchPin,HIGH);
delay(1);
getDigit1(dig_7);
digitalWrite(latchPin,LOW);
shiftOut(dataPin,clockPin,MSBFIRST,512+63 >> 8);
shiftOut(dataPin,clockPin,MSBFIRST,512+dig);
digitalWrite(latchPin,HIGH);
delay(1);
getDigit1(dig_8);
digitalWrite(latchPin,LOW);
shiftOut(dataPin,clockPin,MSBFIRST,1024+63 >> 8);
shiftOut(dataPin,clockPin,MSBFIRST,1024+dig);
digitalWrite(latchPin,HIGH);
delay(1);
}
void displayDigit()  //displays offset (small display)
{
  getDigit(dig_1);
  if (c<=-99 && c>=-999)
  dig=191;
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,256+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,256+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);
  getDigit(dig_2);
  if(c<=-9 && c>=-99)
  dig=191;
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,512+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,512+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);
  getDigit(dig_3);
  if(c<0 && c>=-9)
  dig=191;
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,1024+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,1024+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);
  getDigit(dig_4);
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,2048+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,2048+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);

}
void displayDigit1()  //displays plateau time (small display)
{
  getDigit(dig_1);
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,256+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,256+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);
  getDigit(dig_2);
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,512-128+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,512-128+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);
  getDigit(dig_3);
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,1024+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,1024+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);
  getDigit(dig_4);
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,2048+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,2048+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);

}
void getDigit(int digit)
{
if (digit<0)
digit=-digit;
  switch (digit)
  {
   case 0:
  //dig=64;
  dig=192; //dig+128 for common anode dispaly
  break;
  case 1:
  //dig=121;
  dig=249;
  break;
  case 2:
  //dig=36;
  dig=164;
  break;
  case 3:
  //dig=48;
  dig=176;
  break;
  case 4:
  //dig=25;
  dig=153;
  break;
  case 5:
 // dig=18;
 dig=146;
  break;
  case 6:
  //dig=2;
  dig=130;
  break;
  case 7:
  //dig=120;
  dig=248;
  break;
  case 8:
  //dig=0;
  dig=128;
  break;
  case 9:
  //dig=24;
  dig=152;
  break;
    }
}
void getDigit1(int digit)
{

  switch (digit)
  {
  case 0:
  dig=63; //for common catode display
   break;
  case 1:
  dig=6;
  break;
  case 2:
  dig=91;
  break;
  case 3:
  dig=79;
  break;
  case 4:
  dig=102;
  break;
  case 5:
  dig=109;
  break;
  case 6:
  dig=125;
  break;
  case 7:
  dig=7;
  break;
  case 8:
  dig=127;
  break;
  case 9:
  dig=103;
  break;
  }
}

</adafruit_max31856.h>

 

[marrc]

this is code i am using (some parts were missing):

#include <adafruit_max31856.h> // inclusion of temperature module library
int latchPin1=2;  //for small display
int dataPin1=3;
int clockPin1=4;
int D5=5,D6=6,c=0,switchState,dig,dig_1,dig_2,dig_3,dig_4;
float c1;
int initialstateD5,finalstateD5,initialstateD6,finalstateD6;
int latchPin=7;  //for large display
int dataPin=8;
int clockPin=9;
int temp_sens, temp_read, temp_hyst, dig_5, dig_6, dig_7, dig_8;
//temp_sens=temperature reading of thermocouple, temp_read=temperature on the display, temp_hyst=plateau hysteresis teperature (variable),
//dig_1, dig_2, dig_3, dig_4 = displayed digits from left to right
int dev_pc = 0; // plateau temperature deviation margin percentage (+/- %)
int temp_seek = 400; // temp_seek=tmeperature when plateau detection is initiated
float time_hyst = c1;//=1.8; // plateau wait time (s)
int temp_offset=c; // this value will be subtracted from the actual reading with proper -/+ sign
unsigned long time_res; // time_res=plateau reset time (variable) (ms)
int refresh = 1; // refresh= display hold time (ms)
Adafruit_MAX31856 max = Adafruit_MAX31856(10, 11, 12, 13); // CS, SDI, SDO, SCK pins on the module

void setup()
{
 
  max.begin(); // temperature module initiation
  max.setThermocoupleType(MAX31856_TCTYPE_S); // thermocouple type selection
  pinMode(A3, INPUT_PULLUP); // enabling internal pullup resistance on the Arduino
  pinMode(A5, OUTPUT);
  pinMode (latchPin,OUTPUT);
  pinMode (dataPin,OUTPUT);
  pinMode (clockPin,OUTPUT);
  Serial.begin(9600);
  pinMode (latchPin1,OUTPUT);
pinMode (dataPin1,OUTPUT);
pinMode (clockPin1,OUTPUT);
pinMode (D5,INPUT);  //increment pin
pinMode (D6,INPUT);  // decrement pin
pinMode (A4,INPUT);  //counter select
}

void loop()
{
  switchState= digitalRead(A4);
  if(switchState==LOW) // whole number counter if a4 low
  {
  // put your main code here, to run repeatedly:
  finalstateD5=digitalRead(D5);
  if(finalstateD5 != initialstateD5)
   {
  delay(1);
  finalstateD5=digitalRead(D5);
  if (finalstateD5==HIGH)
  c++;
  Serial.println(c);
  initialstateD5=finalstateD5;
   }
   
dig_1 = c/1000;
dig_2 = (c - 1000 * dig_1) / 100;                      
dig_3 = (c - 1000 * dig_1 - 100 * dig_2) / 10;         
dig_4 = c - 1000 * dig_1 - 100 * dig_2 - 10 * dig_3; 
displayDigit();  //displays offset

  finalstateD6=digitalRead(D6);
  if(finalstateD6 != initialstateD6 )
   {
  delay(1);
  finalstateD6=digitalRead(D6);
  if (finalstateD6==HIGH)
  c--;
  initialstateD6=finalstateD6;
   }
   
dig_1 = c/1000;
dig_2 = (c - 1000 * dig_1) / 100;                      
dig_3 = (c - 1000 * dig_1 - 100 * dig_2) / 10;         
dig_4 = c - 1000 * dig_1 - 100 * dig_2 - 10 * dig_3; 
displayDigit();
  }
  else
  if (switchState=HIGH) // decimal counter if a4 high
  {
  finalstateD5=digitalRead(D5);
  if(finalstateD5 != initialstateD5)
   {
  delay(1);
  finalstateD5=digitalRead(D5);
  if (finalstateD5==HIGH)
  c1=c1+0.01;
  Serial.println(c1);
 
  initialstateD5=finalstateD5;
   }
   
dig_1 = c1*100/1000;
dig_2 = (c1*100 - 1000 * dig_1) / 100;                      
dig_3 = (c1*100 - 1000 * dig_1 - 100 * dig_2) / 10;         
dig_4 = c1*100 - 1000 * dig_1 - 100 * dig_2 - 10 * dig_3; 
displayDigit1(); //displays plateau time

  finalstateD6=digitalRead(D6);
  if(finalstateD6 != initialstateD6 )
   {
  delay(1);
  finalstateD6=digitalRead(D6);
  if (finalstateD6==HIGH)
  c1=c1-0.01;
  initialstateD6=finalstateD6;
   }
   
dig_1 = c1*100/1000;
dig_2 = (c1*100 - 1000 * dig_1) / 100;                      
dig_3 = (c1*100 - 1000 * dig_1 - 100 * dig_2) / 10;        
dig_4 = c1*100 - 1000 * dig_1 - 100 * dig_2 - 10 * dig_3; 
displayDigit1();
  }
  uint8_t fault = max.readFault();
  if (fault & MAX31856_FAULT_OPEN)
  {
    Serial.println("open");
    digitalWrite(A0, LOW); // red LED off
    digitalWrite(A1, LOW); // amber relay off
    digitalWrite(A2, LOW); // green relay off
    digitalWrite(A5, LOW); // red relay off
    temp_sens != max.readThermocoupleTemperature(); // max.readThermocoupleTemperature()=temperature from module (not updated if the condition is not met)
  }
  else
  {
    Serial.println("OK");
    digitalWrite(A2, HIGH); // green LED on
   if(digitalRead(A3)==HIGH) // checking if digital pin 17 is high (high if Red LED is off)
  temp_sens = max.readThermocoupleTemperature(); // max.readThermocoupleTemperature()=temperature from module (updated if the condition is met)
  else                                // checking if digital pin 17 is high (low if Red LED is on)
  temp_sens != max.readThermocoupleTemperature(); // max.readThermocoupleTemperature()=temperature from module (not updated if the condition is not met)
  if (temp_sens <= temp_seek) // checking if temperaure is lower than plateau initiation temperature
  {
    digitalWrite(A0, LOW); // red LED off
    digitalWrite(A1, LOW); // amber LED off
    digitalWrite(A2, HIGH); // green LED on, indicating current temperature is lower than temp_seek
  }
  else
  {
    digitalWrite(A0, LOW); // red LED off
    digitalWrite(A1, HIGH); // amber LED on, indicating plateau detection is active
    digitalWrite(A2, LOW); // green LED off

    if (temp_sens <= (100 + dev_pc) * temp_hyst / 100 && temp_sens >= (100 - dev_pc) * temp_hyst / 100) // checking if the temperature within the platuea's range
    {
      if (millis() - time_res > 1000 * c1) // checking if the waiting time has elapsed
      {
        digitalWrite(A0, HIGH); // red LED on, indicating a plateau is detected
        digitalWrite(A1, LOW); // amber LED off
        digitalWrite(A2, LOW); // green LED off
        digitalWrite(A5, HIGH); // for red relay
      }
    }
    else
    {
      time_res = millis(); // redefining the value of wait time for further iterations
      digitalWrite(A0, LOW); // red LED off
    digitalWrite(A1, HIGH); // amber LED on, indicating plateau detection is active
    digitalWrite(A2, LOW); // green LED off
      temp_hyst = temp_sens; // redefining the value of hysteresis temperature for further iterations
    }
  }
  temp_read = temp_sens-c;
  if (temp_read < 0)
    temp_read = 0;
  if (temp_read > 9999)
    temp_read = 9999;
  dig_5 = temp_read / 1000;                                     // digit 1 temperature value
  dig_6 = (temp_read - 1000 * dig_5) / 100;                     // digit 2 temperature value
  dig_7 = (temp_read - 1000 * dig_5 - 100 * dig_6) / 10;        // digit 3 temperature value
  dig_8 = temp_read - 1000 * dig_5 - 100 * dig_6 - 10 * dig_7;  // digit 4 temperature value
  }
  Serial.println(dig_6);
getDigit1(dig_5);  // gets digits for temp display
digitalWrite(latchPin,LOW);
shiftOut(dataPin,clockPin,MSBFIRST,128+63 >> 8);// shifting out zeros
shiftOut(dataPin,clockPin,MSBFIRST,128+dig);// displaying digit
digitalWrite(latchPin,HIGH);
delay(1);
getDigit1(dig_6);
Serial.println(dig);
digitalWrite(latchPin,LOW);
shiftOut(dataPin,clockPin,MSBFIRST,256+63 >> 8);
shiftOut(dataPin,clockPin,MSBFIRST,256+dig);
digitalWrite(latchPin,HIGH);
delay(1);
getDigit1(dig_7);
digitalWrite(latchPin,LOW);
shiftOut(dataPin,clockPin,MSBFIRST,512+63 >> 8);
shiftOut(dataPin,clockPin,MSBFIRST,512+dig);
digitalWrite(latchPin,HIGH);
delay(1);
getDigit1(dig_8);
digitalWrite(latchPin,LOW);
shiftOut(dataPin,clockPin,MSBFIRST,1024+63 >> 8);
shiftOut(dataPin,clockPin,MSBFIRST,1024+dig);
digitalWrite(latchPin,HIGH);
delay(1);
}
void displayDigit()  //displays offset
{
  getDigit(dig_1);
  if (c<=-99 && c>=-999)
  dig=191;
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,256+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,256+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);
  getDigit(dig_2);
  if(c<=-9 && c>=-99)
  dig=191;
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,512+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,512+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);
  getDigit(dig_3);
  if(c<0 && c>=-9)
  dig=191;
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,1024+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,1024+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);
  getDigit(dig_4);
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,2048+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,2048+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);

}
void displayDigit1()  //displays plateau time
{
  getDigit(dig_1);
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,256+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,256+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);
  getDigit(dig_2);
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,512-128+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,512-128+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);
  getDigit(dig_3);
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,1024+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,1024+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);
  getDigit(dig_4);
  digitalWrite(latchPin1,LOW);
  shiftOut(dataPin1,clockPin1,MSBFIRST,2048+dig>>8);
  shiftOut(dataPin1,clockPin1,MSBFIRST,2048+dig);
  digitalWrite(latchPin1,HIGH);
  delay(1);

}
void getDigit(int digit)
{
if (digit<0)
digit=-digit;
  switch (digit)
  {
   case 0:
  //dig=64;
  dig=192; //dig+128 for common anode dispaly
  break;
  case 1:
  //dig=121;
  dig=249;
  break;
  case 2:
  //dig=36;
  dig=164;
  break;
  case 3:
  //dig=48;
  dig=176;
  break;
  case 4:
  //dig=25;
  dig=153;
  break;
  case 5:
 // dig=18;
 dig=146;
  break;
  case 6:
  //dig=2;
  dig=130;
  break;
  case 7:
  //dig=120;
  dig=248;
  break;
  case 8:
  //dig=0;
  dig=128;
  break;
  case 9:
  //dig=24;
  dig=152;
  break;
    }
}
void getDigit1(int digit)
{

  switch (digit)
  {
  case 0:
  dig=63; //for common catode display
   break;
  case 1:
  dig=6;
  break;
  case 2:
  dig=91;
  break;
  case 3:
  dig=79;
  break;
  case 4:
  dig=102;
  break;
  case 5:
  dig=109;
  break;
  case 6:
  dig=125;
  break;
  case 7:
  dig=7;
  break;
  case 8:
  dig=127;
  break;
  case 9:
  dig=103;
  break;
  }
}

</adafruit_max31856.h>

 

[FenTrac]

In a multiplexed display the brightness of a digit reflects the amount of time the digit is on. The program updates the large display at the end of the loop() function leaving digit 8 on while it begins the loop again. This leaves digit 8 on for a long time compared to the other 3 digits. The program needs to display each digit for a more equal amount of time.

 

[PA3040]

Digits refresh rate and delay should be equal for every digits

Save the values in array and use PORTD for Segments

 

[andre_luis]

You are cascading the output of one chip into another input, which in an offboard arrangement like using Arduino can mean a degradation in signal quality; By the way, you have not shown any detail of the assembly. In this case, you may want to increase the delay to see if the signal stays stable any longer.

 

[marrc]

In a multiplexed display the brightness of a digit reflects the amount of time the digit is on. The program updates the large display at the end of the loop() function leaving digit 8 on while it begins the loop again. This leaves digit 8 on for a long time compared to the other 3 digits. The program needs to display each digit for a more equal amount of time.

sorry for the late reply...actually when i dint get any replies i stopped checking. your reply has given me some hope, but can you help me with the code . what you say makes sense but i just couldnt translate it to code.

cheers,
marrc

 

[FenTrac]

When updating the large display, the program has a delay of 1 millisecond after latching the data. A quick way to test whether timing is the problem would be to remove the delay after dig_8 is updated. The delays after the preceding 3 digits could be increased. This could give a quick visual test. Using a scope on arduino pin 2 (latchPin1) may be a way of measuring the timing intervals.

- - - Updated - - -

Sorry, correction, a scope could be used on Arduino pin 7 (latchPin) for the large display. (LatchPin1 is for the small display).

 

[marrc]

When updating the large display, the program has a delay of 1 millisecond after latching the data. A quick way to test whether timing is the problem would be to remove the delay after dig_8 is updated. The delays after the preceding 3 digits could be increased. This could give a quick visual test. Using a scope on arduino pin 2 (latchPin1) may be a way of measuring the timing intervals.

- - - Updated - - -

Sorry, correction, a scope could be used on Arduino pin 7 (latchPin) for the large display. (LatchPin1 is for the small display).

hi FenTrac,
increasing the delay does brighten the digits but they also start blinking.
now it has boiled down to finding a compromise between digit brightness and digits blinking.
how to make the digits bright and steady?
cheers,
marrc

 

[FenTrac]

Blinking or flickering results when the digits on and off cycle is slower than the eyes persistence of vision. With 4 digits each one is off 3/4 of the time. Refresh needs to be done at least 20 times per second or so. The best way to get the timing of each digit equal without using delays would be to use a timer interrupt to signal when a digit should be updated. One digit of the display updated at each interrupt. At the interrupt a digit from both the small and large display could be refreshed. Then, all the delays could be removed from both refresh cycles. There is a lot of information on the internet on using arduino timer interrupts such as:
https://learn.adafruit.com/multi-tasking-the-arduino-part-2/timers.

 

[baileychic]

It is better to use TimerOne Arduino library and set it up for 2ms or 3ms interrupt and refresh the display in the ISR (interrupt service routine or callback).