Arduino Uno with Breadboard wired up to run a Radio Shack 7 Segment LED.
Wiring looks (and is) messy, due to the strange layout of the pins.
There is a nice table of the segment bytes on the
Wiki 7-seg page. And
a wonderful diagram of the
Arduino Uno by PIGHIXXX here and
many more diagrams of boards & processors from the same
source.
To ALL ARDUINOISTS! There is a wonderful online course offered by UCI, Irvine called Introduction to the Internet of Things and Embedded Systems. It's a six module course working with Arduino, Raspberry Pi, and C programming conducted by Professor Ian Harris who is fantastic. Auditing is free.
The code shown below runs on an Arduino Uno to drive a 7 segment LED from Radio Shack (276-075 which is a National Semiconductor one: ELS321HDB/A) very different from the ones you see in the Arduino tutorials.
// Arduino 7 segment display example software
// http://www.hacktronics.com/Tutorials/arduino-and-7-segment-led.html
// License: http://www.opensource.org/licenses/mit-license.php (Go crazy)
// modified by Clair Dunn http://www.borderlinegeek.com
// ---------------------------------------------------------------------
// common anode section and in-code comments added by Clair Dunn 12/2011
// pin connection comments clarified by Clair Dunn 1/2016
//----------------------------------------------------------------------
// Define the LED digit patterns, from 0 - 9
// Note that these patterns are for common cathode displays
// For common anode displays, change the 1's to 0's and 0's to 1's
// 1 = LED on, 0 = LED off, in this order:
// Arduino pin: 2,3,4,5,6,7,8
/*If you were using a common anode LED you would use this section
byte seven_seg_digits[10][7] = { { 0,0,0,0,0,0,1 }, // = 0 x
{ 1,0,0,1,1,1,1 }, // = 1 x
{ 0,0,1,0,0,1,0 }, // = 2 x
{ 0,0,0,0,1,1,0 }, // = 3 x
{ 1,0,0,1,1,0,0 }, // = 4 x
{ 0,1,0,0,1,0,0 }, // = 5 x
{ 0,1,0,0,0,0,0 }, // = 6 x
{ 0,0,0,1,1,1,1 }, // = 7 x
{ 0,0,0,0,0,0,0 }, // = 8 x
{ 0,0,0,1,1,0,0 } // = 9 x
};
*/
// Arduino pin: 2,3,4,5,6,7,8
byte seven_seg_digits[10][7] = { { 1,1,1,1,1,1,0 }, // = 0
{ 0,1,1,0,0,0,0 }, // = 1
{ 1,1,0,1,1,0,1 }, // = 2
{ 1,1,1,1,0,0,1 }, // = 3
{ 0,1,1,0,0,1,1 }, // = 4
{ 1,0,1,1,0,1,1 }, // = 5
{ 1,0,1,1,1,1,1 }, // = 6
{ 1,1,1,0,0,0,0 }, // = 7
{ 1,1,1,1,1,1,1 }, // = 8
{ 1,1,1,1,0,1,1 } // = 9
};
// set the Arduino pins connected to the LED segments on Radio Shack 276-075
// which is National Semiconductor ELS-321HDB/A (very different from
// standard 7-seg display
// the LED seg lights are, starting with the flat top and moving clockwise:
// A B C D(bottom seg) E F G(middle bar)
// comment list // LEDpin# > Arduino pin# seg name
void setup() {
pinMode(2, OUTPUT); // 14 > 2 A
pinMode(3, OUTPUT); // 13 > 3 B
pinMode(4, OUTPUT); // 8 > 4 C
pinMode(5, OUTPUT); // 7 > 5 D
pinMode(6, OUTPUT); // 6 > 6 E
pinMode(7, OUTPUT); // 2 > 7 F
pinMode(8, OUTPUT); // 1 > 8 G
pinMode(9, OUTPUT); // RDP9 > 9 decimal point
writeDot(0); // start with the "dot" off
}
void writeDot(byte dot) {
digitalWrite(9, dot); // decimal point - pin 9 on Arduino
}
void sevenSegWrite(byte digit) {
byte pin = 2; // Arduino pin where the segment list starts
for (byte segCount = 0; segCount < 7; ++segCount) {
digitalWrite(pin, seven_seg_digits[digit][segCount]);
++pin;
}
}
// displays digits from 9 to 0
void loop() {
for (byte count = 10; count > 0; --count) {
delay(1000);
sevenSegWrite(count - 1);
}
delay(4000);
}
