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Orlando Sian

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mohdazhar

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Components

	Arduino Pro Mini 328 - 5V/16MHz	x 1
	604-WP56BID LEDs PTH Red Blinking LED 625nm, 40 mcd Kingbright	x 5
	Resistor Through Hole 0.4W 100ohms 0.1%	x 5

Tools, APP Software Used etc.

arduino IDE

Arduino

Description

Make a simple persistence-of-vision (POV) display with an Arduino

Here is a simple project using an Arduino and some LEDs. What we are going to learn here today is how to make a POV display or Persistence-Of-Vision display. It is made out of just 6$ worth of components. This tutorial gives will teach you how to make a simple and cheap Arduino POV display. We can use this display as a pocket-sized portable message showing device and tabletop clock.

How Does the POV Display Work?

What is POV(Persistence of Vision)? It can be defined in simple words. When a person sees an object, its image remains in the retina of the eye for a time interval of 1/16th of a second. This phenomenon is known as the persistence of vision. This phenomenon is used in the POV Display to form images. We turn the LEDs on and off in such a way that the different images overlap each other forming letters. For example:

1 2 3 <-- Time

1 1 1 <-- Bulb 1

1 0 0 <-- Bulb 2

1 1 1 <-- Bulb 3

1 0 0 <-- Bulb 4

1 1 1 <-- Bulb 5

Each row represents the 5 LEDs we use to make the Arduino POV display and each column is a time interval. Each element in the row represents the state of the LED at that given time.

At t = 1 Bulbs 1,2,3,4,5 are ON

At t = 2 Bulbs 1,3,5 are ON

This way we can visually see the letter E formed by the LEDs but the time interval would be very small in milliseconds. Due to the short time intervals and the ability of the LEDs to turn ON and OFF very quickly we can see the letter E as all the 3 images merge. As the motor is spinning and time passes, each LED moves from one position to the next, so all these images merge together.

Parts required:

Arduino pro mini
Prefboard
Female socket pin for Arduino
LED 5Pcs. (here I showed green led but. red led is better than green led)
220ohm Resistor 5Pcs
Lipo/Old mobile battery
100rpm gear motor and wheel (for rotary mechanism)

Circuit diagram:

Cut the perf board to the appropriate size. Then connect the LEDs and solder them as shown in the figure below. Then connect the Arduino case (where Arduino is to be placed). Connect the resistors to the positive pins of the LEDs and connect the negative pins together. Then connect the LEDs to the Arduino. The first LED(on the upper side) connects to the Arduino pin 2. Connect the second LED to the Arduino 3rd pin. Connect all LEDs as shown in the circuit diagram. At last, connect a pin for the mobile battery. For plug and play use, connect a switch. If you don’t have a mobile battery, you can also use a 9-volt battery. In this circuit, I have connected a 9-volt battery to the Arduino with a 3V regulator.

Rotary mechanism:

Here I've used the part of an old UPS as the plastic tin. Make a hole in the centre. Then screw the motor there.

Finally, connect the display to the gear motor wheel. Then you have finished the hardware.

Program the Arduino:

Here I'm programming the Arduino pro mini using the ‘FTDI’ USB serial converter if you don’t have this then you can do it using Arduino UNO board click here to see that.

After uploading the code. Now all you need to do is power up the module and the motor used to turn the whole system. And then you would be able to see "Hello World" lighting up when the motor reaches the correct rpm as shown below:

Output:

My work desk at that time :) (2015)

Code

Arduino

int delayTime = 1; 
int charBreak = 2.1; 

int LED1 = 2;
int LED2 = 3;
int LED3 = 4;
int LED4 = 5;
int LED5 = 6;

void setup()
{
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(LED3, OUTPUT);
  pinMode(LED4, OUTPUT);
  pinMode(LED5, OUTPUT); 
}

int a[] = {1, 6, 26, 6, 1};
int b[] = {31, 21, 21, 10, 0};
int c2[] = {14, 17, 17, 10, 0};
int d[] = {31, 17, 17, 14, 0};
int e[] = {31, 21, 21, 17, 0};
int f[] = {31, 20, 20, 16, 0};
int g[] = {14, 17, 19, 10, 0};
int h[] = {31, 4, 4, 4, 31};
int i[] = {0, 17, 31, 17, 0};
int j[] = {0, 17, 30, 16, 0};
int k[] = {31, 4, 10, 17, 0};
int l[] = {31, 1, 1, 1, 0};
int m[] = {31, 12, 3, 12, 31};
int n[] = {31, 12, 3, 31, 0};
int o[] = {14, 17, 17, 14, 0};
int p[] = {31, 20, 20, 8, 0};
int q[] = {14, 17, 19, 14, 2};
int r[] = {31, 20, 22, 9, 0};
int s[] = {8, 21, 21, 2, 0};
int t[] = {16, 16, 31, 16, 16};
int u[] = {30, 1, 1, 30, 0};
int v[] = {24, 6, 1, 6, 24};
int w[] = {28, 3, 12, 3, 28};
int x[] = {17, 10, 4, 10, 17};
int y[] = {17, 10, 4, 8, 16};
int z[] = {19, 21, 21, 25, 0};

int eos[] = {0, 1, 0, 0, 0};
int excl[] = {0, 29, 0, 0, 0};
int ques[] = {8, 19, 20, 8, 0};

void displayLine(int line)
{
  int myline;
  myline = line;
  if (myline>=16) {digitalWrite(LED1, HIGH); myline-=16;} else {digitalWrite(LED1, LOW);}
  if (myline>=8)  {digitalWrite(LED2, HIGH); myline-=8;}  else {digitalWrite(LED2, LOW);}
  if (myline>=4)  {digitalWrite(LED3, HIGH); myline-=4;}  else {digitalWrite(LED3, LOW);}
  if (myline>=2)  {digitalWrite(LED4, HIGH); myline-=2;}  else {digitalWrite(LED4, LOW);}
  if (myline>=1)  {digitalWrite(LED5, HIGH); myline-=1;}  else {digitalWrite(LED5, LOW);} 
}

void displayChar(char c)
{
  if (c == 'a'){for (int i = 0; i <5; i++){displayLine(a[i]);delay(delayTime);}displayLine(0);}
  if (c == 'b'){for (int i = 0; i <5; i++){displayLine(b[i]);delay(delayTime);}displayLine(0);}
  if (c == 'c2'){for (int i = 0; i <5; i++){displayLine(c2[i]);delay(delayTime);}displayLine(0);}
  if (c == 'd'){for (int i = 0; i <5; i++){displayLine(d[i]);delay(delayTime);}displayLine(0);}
  if (c == 'e'){for (int i = 0; i <5; i++){displayLine(e[i]);delay(delayTime);}displayLine(0);}
  if (c == 'f'){for (int i = 0; i <5; i++){displayLine(f[i]);delay(delayTime);}displayLine(0);}
  if (c == 'g'){for (int i = 0; i <5; i++){displayLine(g[i]);delay(delayTime);}displayLine(0);}
  if (c == 'h'){for (int i = 0; i <5; i++){displayLine(h[i]);delay(delayTime);}displayLine(0);} 
  if (c == 'i'){for (int it = 0; it <5; it++){displayLine(i[it]);delay(delayTime);}displayLine(0);}
  if (c == 'j'){for (int i = 0; i <5; i++){displayLine(j[i]);delay(delayTime);}displayLine(0);}
  if (c == 'k'){for (int i = 0; i <5; i++){displayLine(k[i]);delay(delayTime);}displayLine(0);}
  if (c == 'l'){for (int i = 0; i <5; i++){displayLine(l[i]);delay(delayTime);}displayLine(0);}
  if (c == 'm'){for (int i = 0; i <5; i++){displayLine(m[i]);delay(delayTime);}displayLine(0);}
  if (c == 'n'){for (int i = 0; i <5; i++){displayLine(n[i]);delay(delayTime);}displayLine(0);}
  if (c == 'o'){for (int i = 0; i <5; i++){displayLine(o[i]);delay(delayTime);}displayLine(0);}
  if (c == 'p'){for (int i = 0; i <5; i++){displayLine(p[i]);delay(delayTime);}displayLine(0);}
  if (c == 'q'){for (int i = 0; i <5; i++){displayLine(q[i]);delay(delayTime);}displayLine(0);}
  if (c == 'r'){for (int i = 0; i <5; i++){displayLine(r[i]);delay(delayTime);}displayLine(0);}
  if (c == 's'){for (int i = 0; i <5; i++){displayLine(s[i]);delay(delayTime);}displayLine(0);}
  if (c == 't'){for (int i = 0; i <5; i++){displayLine(t[i]);delay(delayTime);}displayLine(0);}
  if (c == 'u'){for (int i = 0; i <5; i++){displayLine(u[i]);delay(delayTime);}displayLine(0);}
  if (c == 'v'){for (int i = 0; i <5; i++){displayLine(v[i]);delay(delayTime);}displayLine(0);}
  if (c == 'w'){for (int i = 0; i <5; i++){displayLine(w[i]);delay(delayTime);}displayLine(0);}
  if (c == 'x'){for (int i = 0; i <5; i++){displayLine(x[i]);delay(delayTime);}displayLine(0);}
  if (c == 'y'){for (int i = 0; i <5; i++){displayLine(y[i]);delay(delayTime);}displayLine(0);}
  if (c == 'z'){for (int i = 0; i <5; i++){displayLine(z[i]);delay(delayTime);}displayLine(0);}
  if (c == '!'){for (int i = 0; i <5; i++){displayLine(excl[i]);delay(delayTime);}displayLine(0);}
  if (c == '?'){for (int i = 0; i <5; i++){displayLine(ques[i]);delay(delayTime);}displayLine(0);}
  if (c == '.'){for (int i = 0; i <5; i++){displayLine(eos[i]);delay(delayTime);}displayLine(0);}
  delay(charBreak);
}

void displayString(char* s)
{
  for (int i = 0; i<=strlen(s); i++)
  {
    displayChar(s[i]);
  }
}

void loop()
{ 
 displayString("hello world")
}

Schematic and Layout

Circuit diagram

POV circuit.jpg