Basic Typewriter

 

Maybe i should call this a Knob writer since characters are entered not through keys but through a knob (potentionmeter).

Why take all this trouble to attach a LCD module or display?

Let's go back to the turing machine. What is a machine? A machine solves a problem. For example: you can create a machine that checks whether a number is even or odd. You can build a machine that checks whether a given number is prime. You can build a machine that converts given message to a cipher(secret message).

So a machine solves a problem. What that means is you give it an input and it will give the answer in form of output. Now we already know Turing machine is the ultimate machine. There are less powerful machines that have limitations on what problems they can solve. But a turing machine can solve any problem. 

So since we are concerned with the output not the input, not the machine not the process involved to build it. Then the question is how do we understand the output. There are many ways to represent the output or the answer that the machine gives. LEDs can be used as output medium. But the problem with LEDs is it takes time to interpret it. For example to read an answer from the leds you need to build a number system and then convert the leds using the number sysstem to the number or the result. 

So the only reason why we build this complex circuit with a LCD module is just to make it easier for us to see the output or the answer of the problem that the machine solves. 

So in summary a Turing machine can solve any problem. Solving a problem means getting the output of the given input. There are many ways to interpret the output. The easiest way is to just display the output directly in the screen. For this the LCD module helps us. LCD module in the arduino world is analogous to computer monitors in the desktop world. 

Here is the demonstration of a basic typewriter that can be used to enter and display characters. 

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