Hellschreiber Clock

Step 6 Digitising "Instructables"

The picture shows how the bitmap of the line of text is digitised.

Taking the leftmost column, for instance, all its pixels are black. So they are all one: 11111

We group together by fours, making two nibbles: 1 1111

These two are then expressed as hexadecimal, for a compact representation: 1 F

Since the characters are five bits high, the first digit is going to be either 0 or 1, and the second digit shall be 0-1, A-F.

The bottom is taken to be the more significant end.

The second column is blank, so all zero: 00 hex.

The third column has the first three ones
followed by two zeroes: 1 1100 -> 1 C

And so on it goes, right up to the very end.

This is all crammed into an include file, called "instructlables.inc". Thus by changing the line specifying the include file in the main program, you can change the bitmap being displayed. In case you make another bimap showing your name, for example, you can put it into a file "yourname.inc" and call it in the main program.