Screens and Displays

We are so used to seeing screens everywhere that we tend to forget just how much work goes into making them display something.

We take it for granted;

that the text will stop at the edge of the screen.
that we can drag objects around the screen at will.
that the screen will scroll up or down.

We even forget that each new movement or change on a screen require erasing the previous drawing.

A screen is nothing much more than an extension of the Blinking light that you just made with your arduino. The only difference is that there are lots of them all working at once.

Think back to the code that made you light switch own and off…

Now imagine controlling 8192 of them at once in order to create the illusion that something bounces of the edge of the screen, or the text scrolls down, or the page turns.

That is the challenge when we start to program displays and screens.

Next time you look at your TV think about the fact that somewhere there is code telling the TV which LEDS to turn of and on and when.

In fact your TV at home probably hasĀ 1920 x 1080 = 2,073,600 pixels that it needs to turn on or off or change colour 30 times a second.

Lets have a look at your OLED screen. As i said before it had 8192 pixels – it has 128 pixels across the top and 64 pixels down the side.


That is a lot of instructions!

Remember that we used an LED light to make our blink experiment.
Your screen is made up of about 8000 of them – the ‘O’ in OLED stands for ‘organic’.

OLED’s use an organic compound that lights up when an electrical current is applied to it.

In the old days screens used to work by quickly painting with a ray of light over the back of a screen. That why old TV’s are big and curved – they needed distance between the light source and the screen.

Now that we use individual LED’s and other forms of light to create images by turning dots on or off we can make much flatter and larger TV’s.