Revival Of Hitachi 671-20 Pen Plotter

The history

The plotter was bought in 1986 in order to plot diagrams on A3 paper, during development of our project PCC (Personal Computer Control), an advanced data aquisition system for IBM-PC clone series of computers. Major part of the development took place during my nine year stay in Scotland from 1989 to 1998. However, the dear Hitachi 671-20 plotter was not used from 1990 to 2020.

The revival idea

Sometimes I make small small projects, demanding a small simple PCB (Printed Circuit Board). I create the schematics and PCB layout in Kicad on Ubuntu Linux machines. Then the layout is printed on transparency with a lazer printer. The transparancy is put over the phot resist covered board, exposed, developedand etched.
One day I though: Why not plot paint directly on the board with the prehistoric plotter?

Understanding HPGL

Sadly I had lost the manual, but finally found the codes needed on the Internet (DXY-codes). Kicad and other programs do not support this long forgotten code, but most will write HPGL. To overcome this, I developed a HPGL to DXY converter, based on the PHP programming language.

Plotting to Parallel Port

There was a parallel port on my old Toshiba Tecra 8000 laptop, running Ubuntu 10.04.
Printing the file translated plotter file did not work. There seemed to control signal and filter issues, as it went through CRUPS. To resolve this, I created a small C-program to write the file directly to the printer port.

GitHub

I have made both hpgl2hita.php and cpy2lp0.c available on GitHub

Cleaning Pens

After thirty years the ink is not as fluent as it used to be :-(