Pov Spinner

So i was thinking: let's make something obvious.
This instructable is on making a spinner with a persistence of vision illusion inside.

• ATtiny 45 ic
• 5 smd led (1206)
• 5 smd resistor (47 Ohm)
• 2 small pieces of pcb
• 1 coin battery (3v - 16mm)
• 8 pieces of metal (for balance)
• a piece of mdf (3mm) for the spinner itself
• a 22mm metal ball-bearing (center)

The wiring is pretty straight forward. I followed the datasheet from Atmel (see screenshot above)

1. The positive pins on the led go to PB0 - PB4 on the ic. I added a resistor in between.
2. negative pins go to GND.
3. Power the ic by connecting the battery to VCC and GND.

In order to put code on the Attiny we need to follow a few steps:

1. Upload the 'ArduinoISP' example to the Arduino board ( located in the examples folder)
2. In Arduino preferences point to https://raw.githubusercontent.com/damellis/attiny... or look for attiny library (by David A. Mellis) and install it
3. In Tools> programmer select the ‘Arduino as ISP’ option
4. Attiny 45 runs on 1 Mhz but can be changed under ’Tools’. That's a bit to slow for persistence of vision: change it to 16 Mhz (normal clock on a regular Arduino)
5. If you do the previous step you have to burn the boot loader. (Tools > burn bootloader)
6. wire the Attiny to the Arduino board (see this page for the exact wiring or look at screenshot above). You also need a 10 uF capacitor between reset and ground to avoid reset (and starting the bootloader)
7. upload the code below to the attiny.
8. done.

arduino / attiny code from the spinner:

<p>int letterSpace;<br>int dotTime;</p>byte invader[] = {1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0};
byte invader2[] = {0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1};
int amount = 12;
void setup()
{
  // setting the ports of the leds to OUTPUT
  pinMode(0, OUTPUT);
  pinMode(1, OUTPUT);
  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  letterSpace = 2;
  dotTime = 1;<br>}<br>

void printImage(byte pix[]){
int y, i;
// image
for (i = 0; i < amount; i++) {
	for (y = 0; y < 5; y++) { 
		digitalWrite(y, pix[y + (i * 5)]);
	}
	delay(dotTime);
}
// space between images
for (y = 0; y < 5; y++) {
	digitalWrite(y, 0);
}
delay(letterSpace);
}

void loop(){
	printImage(invader);
	printImage(invader2);
}

create images

The spinner needs an image to display so i've made a small browser page to create sequences / images for the spinner. (attached as file)

It has an interface of multiple input tags (type: checkbox) and two functions: one to create a new column and one to create the sequence of 0 and 1.

My son (6) had a good time making some invader like sequences.

js:

var start = 8; // start with 8 columns

// a function to create a column of inputs. i have 5 led in the spinner..
function makeColumn() {
  var box = document.createElement("div");
  box.id = "col"; // check css for styling.
  for (var i = 0; i < 5; i++) {
      var input = document.createElement("input");
      input.type = "checkbox";
      box.appendChild(input);
  }
  document.body.appendChild(box);
}

// function attached to load event. Creates the buttons and the columns based on the amount stored in start variable
function create() {
  var b = document.createElement("button");
  b.innerHTML = "create";
  b.addEventListener('click', generate);
  document.body.appendChild(b);
  var b2 = document.createElement("button");
  b2.innerHTML = "add row";
  b2.addEventListener('click', addNew); // event for adding a new column
  document.body.appendChild(b2);
  var input = document.createElement("p");
  input.id = "result";
  document.body.appendChild(input);
  for (var i = 0; i < start; i++) {
      makeColumn();
  }
}

// adds a new column
function addNew() {
   makeColumn();
   start++;
}

// function to generate the sequence of 0 and 1
function generate() {
   var inputs = document.querySelectorAll("input");
   var result = [];
   for (var i = 0; i < inputs.length; i++) {
       var r = inputs[i].checked ? 1 : 0;
       result.push(r);
   }
   var pusher = document.querySelector("#result");
   pusher.innerHTML = result;
}
// start everything when page is loaded.
window.addEventListener('DOMContentLoaded', create);

css:

#col {
   display: inline-block;
}

input {
   display: block;
   -webkit-appearance: none;
   width: 20px;
   height: 20px;
   background: black;
   margin: 1px 1px 0;
}

input:checked {
    background: yellow;
}

The spinner itself was made with NodeBox 3 - an interesting tool for design. The svg output is included.