To accomplish this task you don’t need to buy any expensive software or hardware, only a little knowledge of C program will do and you can build your own musical keyboard software. Before we begin you need to digest some basic concept and logic we are going to use in this program. If you are one of them who spent money to learn basic of computer or any programming language then you must have heard about ASCII (American Standard Code for Information Interchange) characters or codes. We are going to ASCII codes here. This sounds a bit difficult but it is not so.

Logic is that every alphabets on our PC keyboard has some ASCII value like capital A has ASCII value 66, B is equal to 67 and so on. So we will use these values as a frequency range like original musical keyboard has.

The C inbuilt “sound()” function will do this task for us. This “sound()” function instead of using external speaker uses internal speaker located in CPU cabinet. This internal speaker makes beep sound when we boot our PC.

1. #include<stdio.h>
2. #include<conio.h>
3. #include<dos.h>
4. void main()
5. {
6. char ch='y';
7. clrscr();
8. printf("Press X to exit......");
9. while(ch !='X')
10. {
11. ch = getch();
12. sound(10*ch);
13. delay(75);
14. nosound();
15. }
16. }

Line 1-3: Very first three lines of source code include header files, among three header files “dos.h” header file has vital function which will do our task.

Line-4: Forth line is “void main()”  which is the main function of our program and program execution will begin from here.

Line-5: Fifth line is opening brace of main program.

Line-6: In sixth line a character variable has been declared and initialized with character ‘y’.

Line-7: Next line clears the any previous output from output screen.

Line-8: The eighth line prints a line informing user that if he needs to close this program then he/she should press Capital X.

Line-9: Next line is a while loop which keeps looping four lines in it until we press X.

Line-10: Beginning of while loop.

Line-11: In this line of code we store the ASCII value of key pressed by user during runtime. For example if user presses ‘p’ key on keyboard then its corresponding ASCII value, 113 gets store in ‘ch’ variable.

Line-12: The “sound()” will produce sound from pc speaker and in bracket we need to set frequency at which it will buzz. Here we are multiplying 10 with ASCII value available in ch variable. You can change the constant ‘10’ in this line to different integer value and as a result it will change the sound output. Do experiment only with this value.

Line-13: Here “delay()” function determines how long the sound will last (Note: actually “ delay()” function suspends the execution of program). This is determined by value provided in bracket. In our example I have set 75 milliseconds. If you change it to 3000 then sound will be played for 3 seconds.

Line-14: The “nosound()” function works opposite of “sound()” function. It turns off PC speaker. If we won’t use this in our program then speaker will keep buzzing until we close program.

Line-15: End of while loop.

Line-16: End of “main()” function.

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