Frequency and Sound Part 1

To be honest, this was the hardest chapter so far and I think it would be a good idea to get back to it when I finish the book to the end.  I think it was so hard because there were so many new commands and rules introduced.

So I'll start from the basics. 
The rate of high/low signals sent to the speaker from the microcontroller is called the frequency - it determines the tone or pitch of the beep.
Each time a high/low repeats itself is called a cycle - Number of cycles per second (reffered to as Herts, Hz)

The Piezoelectric speaker:
In this activity I will be experimenting with sending some different signals to the Piezoelectric speaker.

 Piezoelectric Speaker Schematic symbol and drawing.

First of all, I built this simple circuit -

How does the Piezo Speaker work?

When a guital string vibrates it causes change in air pressure, and these changes in air pressure are what your ear detects as a tone.  The faster the change in air pressure the higher the pitch, and the slower the change, the lower the pitch.

When high/low signals are applied to the speakers positive terminal, the element inside the piezo speaker, called the piezoelectric element, it vibrates, and causes changes in air pressure.

Programming speaker control:

The FREQOUT command is a convenient way of sending high/low signals to a speaker to make sound.

FREQOUT command syntax -

       FREQOUT Pin, Duration, Freq1 {, Freq2}

Pin - Value you can use to choose what I/O pin to use.

Duration - Value that tells the FREQOUT command how long the tone should play for (in milliseconds).

Freq1 - Argument is used to set the frequency of the tone, in Herts.

Freq2 - An optional Freq2 argument that can be used to mix frequencies.

This is the first test that I did on a Piezoelectric Speaker -

And the coding -

Here are a fiew ActionTones -

Coding -

Mixing Tones:

When you mix 2000 Hz with 20001 Hz, the tone will fade in and out once every second, at a frequency of 1 Hz.  If you mix 2000 Hz with 2002 Hz, it will fade in and out twice a second, and so on.

Mixing Tones Video -

Coding for MixingTones -

I did some programming on that but whats coming up next is the real stuff so check it out -

Musical Notes and Songs:

This is basically an electronic piano.  Rightmost piano keys and their frequencies.

With this, you can create any song, using the FREQOUT command.

Here's some music for you -

DoReMiFaSolLaTiDo:

Coding -

This is the part that gets pretty complicated, but its pretty cool -

Storing and Retrieving sequence of Musical notes:

A good way of saving musical notes is to store them in the EEPROM. (Electrically Erasable Programmable Read-Only Memory).  To do this use the DATA diractive.

Syntax for the DATA diractive -

            {Symbol} DATA {Word} DataItem {, {Word} DataItem,...}

Here is an example of how to use the DATA diractive to store the characters that corespond to musical notes:

      Notes DATA "C","C","G","G","A","A","G"

This is what I put up so far today, I'll put up the rest later or another day.