Lesson 110-6: Measuring DC Voltage and Displaying It on an LED Seven-Segment Display Using Two 74HC595s
This code is to introduce the 74HC595 to drive 8 LED lights and turn them on from 0 to 8 one by one while keeping each LED on. In Project 6: Measuring DC voltage and displaying on the LED display Now, having up to 8 digits seven-segment display, it is time to measure the DC voltage of the Arduino and display it on our display. We used a variable resistor to change the voltage and see the effect immediately on the display.378-Arduino code for 74HC595 chip code 6/6: Display voltage of potentiometer
语言: C++
/*
This is arduino sketch to use 74HC595 shift register to drive 2 to 8 LED Seven Segment Display
Read voltage and display it
it can display integer like 38765 or floatping point number such as 345.7162
Build up to 8 digits Seven-Segment display using 74HC595 Shift Register
Watch full video instruction on YouTube https://youtu.be/xhPXovgFhso
resource page and wiring diagram https://robojax.com/RTJ394
Written and explained by Ahmad Shamshiri on https://youtube.com/@robojax
written by Ahmad Shamshiri
www.Robojax.com https://youTube.com/@robojax
written on March 9 to March 16, 2024
*/
int CLOCK_SHCP_PIN11 = 12;//SHcp pin of 74HC595
int LATCH_STCP_PIN12 = 11;//STcp pin of 74HC595
int DATA_DS_PIN14 = 10;//ds pin of 74HC595
#define DIGITS 5
#define FLOAT_PRECISION 3
#define SHOW_ZERO false
const char type= 'C'; //A for common anode, C for common cathode
int myDigits[DIGITS], digitsLength;
long timeToRemember, decimalPosition=NULL;
bool debug , isFloatingNumber;
int debugDelay = 0;//set the debugging value in milliseonds like 2000. to turn OFF set it to zero
byte digits[] = {B00111111, //0
B00000110, //1
B01011011, //2
B01001111, //3
B01100110, //4
B01101101, //5
B01111101, //6
B00000111, //7
B01111111, //8
B01101111 //9
};
void showNumber(long, long);
int intLength(long);
void setup() {
Serial.begin(9600);
pinMode(CLOCK_SHCP_PIN11, OUTPUT);
pinMode(LATCH_STCP_PIN12, OUTPUT);
pinMode(DATA_DS_PIN14, OUTPUT);
digitalWrite(CLOCK_SHCP_PIN11, LOW);
digitalWrite(LATCH_STCP_PIN12, LOW);
digitalWrite(DATA_DS_PIN14, LOW);
if(debugDelay > 0)
{
debug= true;
}else{
debug= false;
}
}
void loop() {
int sensorValue = analogRead(A0);
// Convert the analog reading (which goes from 0 - 1023) to a voltage (0 - 5V):
float voltage = sensorValue * (5.0 / 1023.0);
showNumberDecimal(voltage, 50);
}
/*
//code has been take from
https://forum.arduino.cc/t/digit-brightness-issue-7-segment-4-digit-display-2-x-74hc595/658032/16
and modified
* @brief shows number on the Seven Segment Display
* @param "num" is integer like 5, or 78 to display
* @param "t" is the delay time to display the digit.
* @return returns none
* Usage to show 18 for 2000 milliseconds: showNumber(18, 2000);
* Written by Ahmad Shamshiri on 08 Mar 2024
* in Ajax, Ontario, Canada
* www.Robojax.com
*/
void showNumber(long number, long t)
{
timeToRemember = millis();
isFloatingNumber = false;
digitsLength = intLength(number);//get the length of digits needed for leading zeros removal
int k=0;
//5658
for(int i=DIGITS-1; i >=0; i--)
{
int divisionValue = (int)(pow(10, k)+.5);
myDigits[i] = (number/ divisionValue) % 10;
k++;
}
// myDigits[4]=(number/1) % 10 ;//59847 gets 7
// myDigits[3]=(number / 10) % 10 ;//59847 gets 4
// myDigits[2]=(number / 100) % 10 ;//59847 gets 8
// myDigits[1]=(number / 1000) % 10 ;//59847 gets 9
// myDigits[0]=(number / 10000) % 10 ;//59847 gets 5
//Serial.println(number);
while( millis() - timeToRemember < t)
// int k=0;
// while( 1)
{
// k++;
shiftDigits();
}
}
void shiftDigits()
{
int digitBits =B11111110;
int leadingZeros = DIGITS - digitsLength;
if(debug)
{
Serial.print("digitsLength:");
Serial.print(digitsLength);
Serial.print(" leadingZeros :");
Serial.println(leadingZeros);
}
for(int i=0; i< DIGITS+1; i++)
{
//Serial.print("Digit: ");Serial.println( myDigits[i]);
//delay(1000);
}
for(int i=0; i < DIGITS; i++)
{
switch (i)
{
case 0:
digitBits =B11111110;
break;
case 1:
digitBits =B11111101;
break;
case 2:
digitBits =B11111011;
break;
case 3:
digitBits =B11110111;
break;
case 4:
digitBits =B11101111;
break;
default:
break;
}
if(i == decimalPosition && isFloatingNumber)
{
digits[myDigits[i]] |= (1 << 7);//set 7th bit to 1 to display decimal
}
//digits[myDigits[i]] |= (1 << 7);//set 7th bit to 1 to display decimal
// Serial.print("myDigits[");
// Serial.print(i);
// Serial.print("] =");
// Serial.println(myDigits[i]);
//this loop below is to turn off the leading zeros if set the at the top of the code
int segmentsToDisplay =digits[ myDigits[i]] ;//remember the segments value for leading zero removal
if(!SHOW_ZERO)
{
for(int k=0; k < leadingZeros; k++)
{
if(i==k)
{
segmentsToDisplay =B00000000;//turn off all segments
break;
}
}
}
if(type =='A')
{
segmentsToDisplay = ~segmentsToDisplay;//toggle all bits for common anode display type
}
if(debug)
{
Serial.print("i-:");
Serial.print(i);
Serial.print(" digitBits:");
Serial.print(digitBits, BIN);
Serial.print(" segmentsToDisplay:");
Serial.println(segmentsToDisplay, BIN);
Serial.print(" digits[ myDigits[");
Serial.print(i);
Serial.print("]]) = ");
Serial.println(digits[ myDigits[i]], BIN);
}
digitalWrite(LATCH_STCP_PIN12, LOW);
shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, digitBits);
shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, segmentsToDisplay);
digitalWrite(LATCH_STCP_PIN12, HIGH);
delay(1);
if( i == decimalPosition && isFloatingNumber)
{
digits[myDigits[i]] ^= (1 << 7);//toggle the decimal bit to OFF
}
if(debug)
{
delay(debugDelay);
}
}
// int digitBits =B00100000;//keeps all digits ON with ditigtBits << 1 for [3] and << 2 for [2]
//digitBits =B00000001;
// Serial.print(number);
// Serial.print("digitBits:");
// Serial.print(digitBits, BIN);
// Serial.print(" for digit0: ");
// Serial.println(myDigits[0]);
// digitalWrite(LATCH_STCP_PIN12, LOW);
// shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, digitBits );
// shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, digits[ myDigits[4]]);
// digitalWrite(LATCH_STCP_PIN12, HIGH);
// Serial.println(myDigits[4]);
// delay(3000);
// digitalWrite(LATCH_STCP_PIN12, LOW);
// shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, digitBits << 1);
// shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, digits[ myDigits[3]]);
// digitalWrite(LATCH_STCP_PIN12, HIGH);
// Serial.println(myDigits[3]);
// delay(3000);
// digitalWrite(LATCH_STCP_PIN12, LOW);
// shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, digitBits << 2);
// shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, digits[ myDigits[2]]);
// digitalWrite(LATCH_STCP_PIN12, HIGH);
// Serial.println(myDigits[2]);
// delay(3000);
// digitalWrite(LATCH_STCP_PIN12, LOW);
// shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, digitBits << 3);
// shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, digits[ myDigits[1]]);
// digitalWrite(LATCH_STCP_PIN12, HIGH);
// Serial.println(myDigits[1]);
// delay(3000);
// digitalWrite(LATCH_STCP_PIN12, LOW);
// shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, digitBits << 4);
// shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, digits[myDigits[0]]);
// digitalWrite(LATCH_STCP_PIN12, HIGH);
// Serial.println(myDigits[0]);
// delay(3000);
}
void showNumberDecimal(float floatNumber, long t)
{
timeToRemember = millis();
isFloatingNumber = true;
// //if we have 2.8
// int d2 = num;//2.8 becomes 2
// int d1 = (int) (num *10);
// d1 = d1 % 10;// gets 8
// digits[d2] |= (1 << 7);//set 7th bit to 1 to display decimal
floatToInt(floatNumber);
if(debug)
{
Serial.print("Decimal position:");
Serial.println(decimalPosition);
}
while( millis() - timeToRemember < t)
{
shiftDigits();
// digitalWrite(LATCH_STCP_PIN12, LOW);
// shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, B00000001);
// shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, digits[d2]);
// digitalWrite(LATCH_STCP_PIN12, HIGH);
// delay(1);
// digitalWrite(LATCH_STCP_PIN12, LOW);
// shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, B00000010);
// shiftOut(DATA_DS_PIN14, CLOCK_SHCP_PIN11, MSBFIRST, digits[d1]);
// digitalWrite(LATCH_STCP_PIN12, HIGH);
// delay(1);
}
//digits[d1] ^= (1 << 7);//toggle the decimal bit to OFF
}
void floatToInt(float floatNumber)
{
char charNumber[DIGITS+1];//create char array for one extra char for decimal place
dtostrf(floatNumber, DIGITS+1, FLOAT_PRECISION, charNumber);//
//now charNumber holds the float value as char array
String stringNumber =charNumber;//convert it to String to amke it easy to work with
if(debug)
{
Serial.print("===== ");Serial.print(floatNumber, FLOAT_PRECISION); Serial.println(" ===");
Serial.print("charNumber: ");
Serial.println(charNumber);
Serial.print("stringNumber: ");Serial.println(stringNumber);
}
////get the position of decimal place
for(int i=0; i< DIGITS+1; i++)
{
if(charNumber[i] =='.')
{
decimalPosition =i;//get the position of decimal point
break;
}
}
//this array is used to compare each char in the stringNumber variable
//so we assign integer for that value
char charDigits[]={'0','1','2','3','4','5','6','7','8','9'};
stringNumber.remove(decimalPosition, 1);//remove . the decimal point from string
decimalPosition--;//after removing the decimal point, then we should subtract the position
if(debug)
{
Serial.print("stringNumber(. removed): ");Serial.println(stringNumber);
}
digitsLength =0;//need this to turn off leadzing zeros
// "8763"
for(int i=0; i< stringNumber.length(); i++)
{
//check each stringNumber.charAt(i) agains charDigits[n]
for(int n=0; n <=9; n++)
{
if(stringNumber.charAt(i) ==charDigits[n] )
{
myDigits[i]=n;//save the digit in the array
digitsLength++;
break;
}
}//inner loo end
}//for loop end
}//floatToInt end
/*
gets length of long integer
@param number is long integer to the its length
@return the lenght from 0 to 9
*/
int intLength(long number)
{
int Length = 0;
if(number > 99999999)Length = 9;
else if(number > 9999999)Length = 8;
else if(number > 999999)Length = 7;
else if(number > 99999)Length = 6;
else if(number > 9999)Length = 5;
else if(number > 999)Length = 4;
else if(number > 99)Length = 3;
else if(number > 9)Length = 2;
else if(number < 9 && number > 0)Length = 1;
else Length = 0;
return Length;
}//intLength ends资源与参考
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