Erika3004

Encoding

The Erika3004 Typewriter uses a proprietary encoding NOT compatible with ASCII, Unicode, etc.
Therefore, software is needed to convert the RAW encoding (or DDR ASCII (GDR ASCII) as we call it ;) ) into something more useful (by modern standands) like ASCII.

A table of all available characters and their hexadecimal value can be found in the manual (Erika-IF2014_AnwenderHandbuch) as Appendix E on page 10.
It also has a list of the most used control characters on page 11 (Appendix F).
A complete list can be found here.

We implemented the conversion in python using a json-file which contains all characters and their hexadecimal values.
Find it in the erika directory (that name was chosen because python module names are based on directory names).

The implementation for Arduino uses hard-coded arrays instead.
Find it in the arduino directory.

Hardware

If you are a proud owner of an Erika 3004 Electronic Typewriter, you might want to check out this "ServiceManual".

Description of the Erica connector:

More information can be found here (German):
http://hc-ddr.hucki.net/wiki/doku.php/z9001/erweiterungen/s3004

A schematic of our Arduino based interface can be found on EasyEDA.

DDR-Halbleiter - Kurzdatenblätter und Vergleichsliste

Software

Arduino Sketch

Located in arduino directory.

The arduino sketch should be compilable for any Arduino that has at least one hardware UART (hardware serial).
TODO: Test on Mini, Nano

The arduino will communicate with your PC using the default hardware serial, which is usually connected to a USB-to-serial converter.
It will use a software serial to communicate with the Erika3004.
More information about SoftwareSerial can be found on the Arduino-Website. In erika.ino, you can set the following constants:

Remember: Serial connections are connected with cross-over. This means RX on the Arduino connects to TX on the Erika and vice versa.

Name	Description	Default Value	Comment
PC_BAUD	Baudrate used to communicate with the pc	9600	You can change this to fit your needs.
RTS_PIN	Pin that is connected to the ready to send pin of the Erika.	3	You can change this to any available digital input pin on your arduino.
ERIKA_RX	Recieve pin of the SoftwareSerial to communicate with Erika.	10	Check the limitations section on the Arduino-Website, to find out which pins can be used by SoftwareSerial.
ERIKA_TX	Transmit pin of the SoftwareSerial to communicate with Erika.	11	Check the limitations section on the Arduino-Website, to find out which pins can be used by SoftwareSerial.
ERIKA_BAUD	Baudrate used by the Erika3004.	1200	DON'T CHANGE THIS! The Erika3004 will only work with 1200 Baud!

Translation from ASCII to DDR-ASCII is done using arrays defined in ddr2ascii.h and ascii2ddr.h.

Let's build a secret chat system using 2 of these. :)

Installation

Install python3

sudo apt-get install python3

Install pip package manager for python

sudo apt-get install python3-pip

Install necessary packages

pip3 install -r requirements.txt

Install tab autocompletion for erika.sh

If you want to use the command-line interface (CLI) of erika.sh with automated completion if you press the character, run the install script:

./activate_autocomplete_for_erika_sh.sh

The script may fail under certain circumstances - requiring SUDO permissions. In this case, try again like this:

sudo ./activate_autocomplete_for_erika_sh.sh

ASCII art

Create ASCII art for printout

• install Imagemagick's convert tool

sudo apt install imagemagick 

• install jp2a

sudo apt install jp2a

• convert png files on the command line like this:
  • leave one dimension unspecified to keep the original ratio

convert ubuntu-logo32.png jpg:- | jp2a - --width=80 --height=80 > ascii_art.txt

Print ASCII art

The erika.sh command-line utility provides convenience functions to have Erika print a given ASCII art file.

It offers the following built-in rendering strategies:

• LineByLine
  • render the given image line by line
• Interlaced
  • render the given image, every even line first (starting count at 0), every odd line later
• PerpendicularSpiralInward
  • render the given image, spiralling inward to the middle while going parallel to X or Y axis all the time
  • implementation goes clockwise, starting at the upper left corner
• RandomDotFill
  • render the given image, printing one random letter at a time
• ArchimedeanSpiralOutward
  • render the given image, starting from the middle, following an Archimedean spiral as closely as possible

For further information, simply call
./erika.sh -h

Print images

This works mostly just like for ASCII art images, described in the previous section.

If as a file parameter for the CLI you specify an image file, it will be printed pixel by pixel, according to the specified rendering strategy, like before for ASCII art images.

Play "Tic Tac Toe"

To run the Tic Tac Toe game in a simulated environment, call this in your shell:

 ./erika.sh tictactoe -d

Play against the real Erika machine (use the right port as parameter):

./erika.sh tictactoe -p "/dev/ttyACM0"

To control the game:

• use the WASD keys to move
• use the space bar or enter key to make your mark at the current position

Testing

Run unit tests

For now, call this in bash:

./run_unittests.sh

Run integration tests

For now, call this in bash:

./run_integrationtests.sh