Hey guys! This is an Instructable for making your own ATtiny85/45 5 LED POV (Persistence Of Vision) display!
This is my second Instructable, also for the Elemental LED contest, so drop a comment and vote it up!
The total parts cost for this POV display is under $10! (If you get the parts from a wholesale supplier, like Mouser or Digi-Key)
I apologize for all the horribly blurry pictures, I’m using my iPod touch to take them (what a crap camera on that one, right?) I will be taking the pictures with a different camera for my future Instructables. 🙂
Step: 1 Parts List
Things you will need:
Parts:
1x ATtiny85/45 microcontroller
1x 8 pin DIP socket
1x 2 position slide switch
1x 100-220 Ohm resistor
1x 2 AA battery pack
5x LEDs (any color) (I used rectangular 2x5mm LEDs because they fit right next to each other without a gap on the perfboard)
Some bits of wire
Some perfboard
Tools:
1x AVR programmer (can be an Arduino, go here for instructions)
1x Saw or Dremel for cutting the perfboard down to size
Step: 2 Circuit Schematic
Here’s the schematic for the circuit. I have attached the Eagle .sch file at the bottom.
Step: 3 Program the ATtiny MCU
I made an Arudino sketch to upload to the ATtiny, so the Arduino would be the logical choice for uploading to the ATtiny. You can find a guide on how to do this here. (You can skip the guide if you already know how)
After you followed the guide above, hook up the ATtiny, and upload the sketch.
To change the message displayed, open the sketch, and scroll all the way down to the bottom. There will be a line that says “displayString(“wow!!”);”, you can change the text inside quotes if you want to change the message. After you have done that, just re-upload the sketch to the ATtiny and you’re ready to go.
Here’s the code (for some reason it’s not letting me upload the .pde file, it keep saying either HTTP Error or ir gets stuck at 100%. If anybody knows how to fix this please do tell.):
int delayTime = 2; //sub-char delay time
int charBreak = 5; //char delay time
int LED1 = 0;
int LED2 = 1;
int LED3 = 2;
int LED4 = 3;
int LED5 = 4;
void setup()
{
pinMode(LED1, OUTPUT);
pinMode(LED2, OUTPUT);
pinMode(LED3, OUTPUT);
pinMode(LED4, OUTPUT);
pinMode(LED5, OUTPUT);
pinMode(7, INPUT);
}
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 == ‘c’){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(“wow!!”);
}
Step: 4 Breadboard it!
Now assemble the circuit on a breadboard to make sure that it is working properly. Power it with a 3 volt power source (such as 2 AA batteries or a CR2032 3V coin cell battery)
Make sure that the LEDs are in the right order. I will put the LED order first, and then the ATtiny pin it connects to.
Top LED – pin 3
Second LED from top – pin 2
Middle LED – pin 7
Second LED from bottom – pin 6
Bottom LED – pin 5
For more detail: $10 ATtiny85/45 POV display!! (works really well)
