4 DIGITOS 7 SEGMENTOS.
Contador.
Here is a simple example of how to connect up a 4-digit 7-segment display to the Arduino UNO board and make a countdown timer. The display starts at a predetermined value and counts down every second.
When it reaches zero, the display flashes. You can easily add a buzzer to give an audable indication. Great for a simple egg timer or other countdown timer project
Wiring connections are listed in the Arduino Sketch which is shown below.
CÓDIGO
/* 6-13-2011 Spark Fun Electronics 2011 Nathan Seidle This version modified by www.hobbytronics.co.uk as a countdown timer Ideal as a simple egg timeror other timer. Easily add a buzzer This code is public domain but you buy me a beer if you use this and we meet someday (Beerware license). 4 digit 7 segment display: http://www.sparkfun.com/products/9483 Datasheet: http://www.sparkfun.com/datasheets/Components/LED/7-Segment/YSD-439AR6B-35.pdf This is an example of how to drive a 7 segment LED display from an ATmega without the use of current limiting resistors. This technique is very common but requires some knowledge of electronics - you do run the risk of dumping too much current through the segments and burning out parts of the display. If you use the stock code you should be ok, but be careful editing the brightness values. This code should work with all colors (red, blue, yellow, green) but the brightness will vary from one color to the next because the forward voltage drop of each color is different. This code was written and calibrated for the red color. This code will work with most Arduinos but you may want to re-route some of the pins. 7 segments 4 digits 1 colon = 12 pins required for full control */ int digit1 = 11; //PWM Display pin 1 int digit2 = 10; //PWM Display pin 2 int digit3 = 9; //PWM Display pin 6 int digit4 = 6; //PWM Display pin 8 //Pin mapping from Arduino to the ATmega DIP28 if you need it //http://www.arduino.cc/en/Hacking/PinMapping int segA = A1; //Display pin 14 int segB = 3; //Display pin 16 int segC = 4; //Display pin 13 int segD = 5; //Display pin 3 int segE = A0; //Display pin 5 int segF = 7; //Display pin 11 int segG = 8; //Display pin 15 int start_num=30; // Number to countdown from unsigned long time; void setup() { pinMode(segA, OUTPUT); pinMode(segB, OUTPUT); pinMode(segC, OUTPUT); pinMode(segD, OUTPUT); pinMode(segE, OUTPUT); pinMode(segF, OUTPUT); pinMode(segG, OUTPUT); pinMode(digit1, OUTPUT); pinMode(digit2, OUTPUT); pinMode(digit3, OUTPUT); pinMode(digit4, OUTPUT); pinMode(13, OUTPUT); } void loop() { //long startTime = millis(); if((millis()/1000) < start_num){ displayNumber(start_num -(millis()/1000)); } else { // reached zero, flash the display time=millis(); while(millis() < time+200) { displayNumber(0); // display 0 for 0.2 second } time=millis(); while(millis() < time+200) { lightNumber(10); // Turn display off for 0.2 second } } //while( (millis() - startTime) < 2000) { //displayNumber(1217); //} //delay(1000); } //Given a number, we display 10:22 //After running through the 4 numbers, the display is left turned off //Display brightness //Each digit is on for a certain amount of microseconds //Then it is off until we have reached a total of 20ms for the function call //Let's assume each digit is on for 1000us //If each digit is on for 1ms, there are 4 digits, so the display //is off for 16ms. //That's a ratio of 1ms to 16ms or 6.25% on time (PWM). //Let's define a variable called brightness that varies from: //5000 blindingly bright (15.7mA current draw per digit) //2000 shockingly bright (11.4mA current draw per digit) //1000 pretty bright (5.9mA) //500 normal (3mA) //200 dim but readable (1.4mA) //50 dim but readable (0.56mA) //5 dim but readable (0.31mA) //1 dim but readable in dark (0.28mA) void displayNumber(int toDisplay) { #define DISPLAY_BRIGHTNESS 500 #define DIGIT_ON HIGH #define DIGIT_OFF LOW long beginTime = millis(); for(int digit = 4 ; digit > 0 ; digit--) { //Turn on a digit for a short amount of time switch(digit) { case 1: digitalWrite(digit1, DIGIT_ON); break; case 2: digitalWrite(digit2, DIGIT_ON); break; case 3: digitalWrite(digit3, DIGIT_ON); break; case 4: digitalWrite(digit4, DIGIT_ON); break; } //Turn on the right segments for this digit lightNumber(toDisplay % 10); toDisplay /= 10; delayMicroseconds(DISPLAY_BRIGHTNESS); //Display digit for fraction of a second (1us to 5000us, 500 is pretty good) //Turn off all segments lightNumber(10); //Turn off all digits digitalWrite(digit1, DIGIT_OFF); digitalWrite(digit2, DIGIT_OFF); digitalWrite(digit3, DIGIT_OFF); digitalWrite(digit4, DIGIT_OFF); } while( (millis() - beginTime) < 10) ; //Wait for 20ms to pass before we paint the display again } //Given a number, turns on those segments //If number == 10, then turn off number void lightNumber(int numberToDisplay) { #define SEGMENT_ON LOW #define SEGMENT_OFF HIGH switch (numberToDisplay){ case 0: digitalWrite(segA, SEGMENT_ON); digitalWrite(segB, SEGMENT_ON); digitalWrite(segC, SEGMENT_ON); digitalWrite(segD, SEGMENT_ON); digitalWrite(segE, SEGMENT_ON); digitalWrite(segF, SEGMENT_ON); digitalWrite(segG, SEGMENT_OFF); break; case 1: digitalWrite(segA, SEGMENT_OFF); digitalWrite(segB, SEGMENT_ON); digitalWrite(segC, SEGMENT_ON); digitalWrite(segD, SEGMENT_OFF); digitalWrite(segE, SEGMENT_OFF); digitalWrite(segF, SEGMENT_OFF); digitalWrite(segG, SEGMENT_OFF); break; case 2: digitalWrite(segA, SEGMENT_ON); digitalWrite(segB, SEGMENT_ON); digitalWrite(segC, SEGMENT_OFF); digitalWrite(segD, SEGMENT_ON); digitalWrite(segE, SEGMENT_ON); digitalWrite(segF, SEGMENT_OFF); digitalWrite(segG, SEGMENT_ON); break; case 3: digitalWrite(segA, SEGMENT_ON); digitalWrite(segB, SEGMENT_ON); digitalWrite(segC, SEGMENT_ON); digitalWrite(segD, SEGMENT_ON); digitalWrite(segE, SEGMENT_OFF); digitalWrite(segF, SEGMENT_OFF); digitalWrite(segG, SEGMENT_ON); break; case 4: digitalWrite(segA, SEGMENT_OFF); digitalWrite(segB, SEGMENT_ON); digitalWrite(segC, SEGMENT_ON); digitalWrite(segD, SEGMENT_OFF); digitalWrite(segE, SEGMENT_OFF); digitalWrite(segF, SEGMENT_ON); digitalWrite(segG, SEGMENT_ON); break; case 5: digitalWrite(segA, SEGMENT_ON); digitalWrite(segB, SEGMENT_OFF); digitalWrite(segC, SEGMENT_ON); digitalWrite(segD, SEGMENT_ON); digitalWrite(segE, SEGMENT_OFF); digitalWrite(segF, SEGMENT_ON); digitalWrite(segG, SEGMENT_ON); break; case 6: digitalWrite(segA, SEGMENT_ON); digitalWrite(segB, SEGMENT_OFF); digitalWrite(segC, SEGMENT_ON); digitalWrite(segD, SEGMENT_ON); digitalWrite(segE, SEGMENT_ON); digitalWrite(segF, SEGMENT_ON); digitalWrite(segG, SEGMENT_ON); break; case 7: digitalWrite(segA, SEGMENT_ON); digitalWrite(segB, SEGMENT_ON); digitalWrite(segC, SEGMENT_ON); digitalWrite(segD, SEGMENT_OFF); digitalWrite(segE, SEGMENT_OFF); digitalWrite(segF, SEGMENT_OFF); digitalWrite(segG, SEGMENT_OFF); break; case 8: digitalWrite(segA, SEGMENT_ON); digitalWrite(segB, SEGMENT_ON); digitalWrite(segC, SEGMENT_ON); digitalWrite(segD, SEGMENT_ON); digitalWrite(segE, SEGMENT_ON); digitalWrite(segF, SEGMENT_ON); digitalWrite(segG, SEGMENT_ON); break; case 9: digitalWrite(segA, SEGMENT_ON); digitalWrite(segB, SEGMENT_ON); digitalWrite(segC, SEGMENT_ON); digitalWrite(segD, SEGMENT_ON); digitalWrite(segE, SEGMENT_OFF); digitalWrite(segF, SEGMENT_ON); digitalWrite(segG, SEGMENT_ON); break; case 10: digitalWrite(segA, SEGMENT_OFF); digitalWrite(segB, SEGMENT_OFF); digitalWrite(segC, SEGMENT_OFF); digitalWrite(segD, SEGMENT_OFF); digitalWrite(segE, SEGMENT_OFF); digitalWrite(segF, SEGMENT_OFF); digitalWrite(segG, SEGMENT_OFF); break; } }
