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.

Step 1: Parts and Wiring

• 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.

Step 2: Programming the Ic

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);
}

Step 3: Simple Spinner Images

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.