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HP 7440A

Hp 7440A advertisement image

todo:

• ☑ needs electricity cable
• ☑ check if it works with 230V
  • yes, it works with 230v, but it needs a special power supply (0v - 10v - 20v) - info in the hp museum
• ☑ search for operation manual
• ☑ 3d print pen holders
• ☐ mod: cutout plastic to use regular pens

Specs

• A4 paper
• user manual: https://userequip.com/files/specs/1504/HP%207440A%20Operating.pdf
• in the HP museum: http://hpmuseum.net/display_item.php?hw=80
• works with a parallel port, and is currently connected with an adapter to a serial port, connected to another adapter to USB

Pen plotters are used for technical drawings, but got replaced by dot matrix printers.

Turn the plotter on

When the plotter is connected to the RPI, the plotter can be found at: /dev/ttyUSB0

Step 0 Let’s see if it works! We first send a command to the printer…

$ echo 'PD100,100' > /dev/ttyUSB0

What does PD100,100 mean? PD = pen down 100,100 = position x = 100, y = 100

adjust speed To adjust the speed (how many instructions can i send to the plotter at the same time):

$ stty -F /dev/ttyUSB0 9600

Step 1

Put the paper in

Push the paper button

Step 2

Push the pen button

Step 3

Send a command to print something

To print the demo page

Load paper

Select pen Then press ENTER (keep it pressed) and press LOAD

Inkscape

https://inkscape.org/

We take the logo of the pzwiki as an example file:

Which actually comes from ted nelson’s book “computer lib dream machine” (see bootleg library).

• open an image
• select “Path” > “trace bitmap”
• select “Save” > “save as” and save the file as myfile.hpgl

Chiplotle

https://chiplotle.readthedocs.io/en/latest/index.html Chiplotle is a tool written in python that can be used to work with pen plotters.

Start chiplotle

$ chiplotle

Make sure your plotter is connected and on. If everything is oke, chiplotle will find the pen plotter automagically.

Choose the pen plotter that “fits your hardware”, which is number 11 in our case.

Use chiplotle

Make a HPGL file and upload it to the RPI that is connected to the plotter.

Navigate to the folder where your file is.

Send it to the plotter with the following command:

$ plotter.write_file("filename.hpgl")

Stop while chiplotle is running

CTRL+C

Take the paper out Press the “load” button (the white button with the two roles and paper in between).

Close chiplotle

$ close()

Change buffer size plotter.buffer_size = 512

send files to the RPI

You can do this with scp

$ scp yourfile.hpgl pi@145.24.131.92: