Arduino Shift Resistor with 8 LEDs

SOURCE CODE:

// Pin definitions: // The 74HC595 uses a type of serial connection called SPI // (Serial Peripheral Interface) that requires three pins:

int datapin = 2; int clockpin = 3; int latchpin = 4;

// We'll also declare a global variable for the data we're // sending to the shift register:

byte data = 0;

void setup() { // Set the three SPI pins to be outputs:

pinMode(datapin, OUTPUT); pinMode(clockpin, OUTPUT); pinMode(latchpin, OUTPUT); }

void loop() { oneAfterAnother(); // All on, all off oneOnAtATime(); // Scroll down the line pingPong(); // Like above, but back and forth

randomLED(); // Blink random LEDs marquee();

binaryCount(); // Bit patterns from 0 to 255 }

void shiftWrite(int desiredPin, boolean desiredState)

bitWrite(data,desiredPin,desiredState); // Now we'll actually send that data to the shift register. // The shiftOut() function does all the hard work of // manipulating the data and clock pins to move the data // into the shift register:

shiftOut(datapin, clockpin, MSBFIRST, data);

// Once the data is in the shift register, we still need to // make it appear at the outputs. We'll toggle the state of // the latchPin, which will signal the shift register to "latch" // the data to the outputs. (Latch activates on the high-to // -low transition).

digitalWrite(latchpin, HIGH); digitalWrite(latchpin, LOW); }

/* oneAfterAnother()

This function will light one LED, delay for delayTime, then light the next LED, and repeat until all the LEDs are on. It will then turn them off in the reverse order. */

void oneAfterAnother() { int index; int delayTime = 100; // Time (milliseconds) to pause between LEDs // Make this smaller for faster switching

// Turn all the LEDs on: // This for() loop will step index from 0 to 7 // (putting "++" after a variable means add one to it) // and will then use digitalWrite() to turn that LED on. for(index = 0; index <= 7; index++) { shiftWrite(index, HIGH); delay(delayTime); }

// Turn all the LEDs off:

// This for() loop will step index from 7 to 0 // (putting "--" after a variable means subtract one from it) // and will then use digitalWrite() to turn that LED off. for(index = 7; index >= 0; index--) { shiftWrite(index, LOW); delay(delayTime); } }

/* oneOnAtATime()

This function will step through the LEDs, lighting one at at time. */

void oneOnAtATime() { int index; int delayTime = 100; // Time (milliseconds) to pause between LEDs // Make this smaller for faster switching // step through the LEDs, from 0 to 7 for(index = 0; index <= 7; index++) { shiftWrite(index, HIGH); // turn LED on delay(delayTime); // pause to slow down the sequence shiftWrite(index, LOW); // turn LED off } }

/* pingPong()

This function will step through the LEDs, lighting one at at time, in both directions. */

void pingPong() { int index; int delayTime = 100; // time (milliseconds) to pause between LEDs // make this smaller for faster switching // step through the LEDs, from 0 to 7 for(index = 0; index <= 7; index++) { shiftWrite(index, HIGH); // turn LED on delay(delayTime); // pause to slow down the sequence shiftWrite(index, LOW); // turn LED off }

// step through the LEDs, from 7 to 0 for(index = 7; index >= 0; index--) { shiftWrite(index, HIGH); // turn LED on delay(delayTime); // pause to slow down the sequence shiftWrite(index, LOW); // turn LED off } }

/* randomLED()

This function will turn on random LEDs. Can you modify it so it also lights them for random times? */

void randomLED() { int index; int delayTime = 100; // time (milliseconds) to pause between LEDs // make this smaller for faster switching // The random() function will return a semi-random number each // time it is called. See http://arduino.cc/en/Reference/Random // for tips on how to make random() more random. index = random(8); // pick a random number between 0 and 7 shiftWrite(index, HIGH); // turn LED on delay(delayTime); // pause to slow down the sequence shiftWrite(index, LOW); // turn LED off }

/* marquee()

This function will mimic "chase lights" like those around signs. */

void marquee() { int index; int delayTime = 200; // Time (milliseconds) to pause between LEDs // Make this smaller for faster switching // Step through the first four LEDs // (We'll light up one in the lower 4 and one in the upper 4) for(index = 0; index <= 3; index++) { shiftWrite(index, HIGH); // Turn a LED on shiftWrite(index+4, HIGH); // Skip four, and turn that LED on delay(delayTime); // Pause to slow down the sequence shiftWrite(index, LOW); // Turn both LEDs off shiftWrite(index+4, LOW); } }

void binaryCount() { int delayTime = 1000; // time (milliseconds) to pause between LEDs // make this smaller for faster switching // Send the data byte to the shift register:

shiftOut(datapin, clockpin, MSBFIRST, data);

// Toggle the latch pin to make the data appear at the outputs:

digitalWrite(latchpin, HIGH); digitalWrite(latchpin, LOW); // Add one to data, and repeat! // (Because a byte type can only store numbers from 0 to 255, // if we add more than that, it will "roll around" back to 0 // and start over).

data++;

// Delay so you can see what's going on:

delay(delayTime); }