plotbot

Raspberry Pi code that drives stepper motors and sensors on an old 3D printer allowing for 2D images to be drawn on the base plate with a pen.

Demo Video: https://www.youtube.com/watch?v=gwPj64Iiqy4

plotbot.py

This is a command line interface program that allows for precise movement of the print head along a single axis. Each movement will report the current position of the print head and save this to a configuration file ~/.plotbot.json See example_plotbot.json in this repo for example

This script is useful for calibrating and saving known positions whenever the physical setup is changed. e.g. if a different print surface or writing implement is used. e.g. paper vs white board, or ballpoint pen vs crayon. After defining configuration values for the current physical setup, the json file can be saved as a "profile" for later reuse of that physical configuration in special purpose applications.

Usage

$ ./plotbot.py -h - Will display usage information.

Calibration

If print heads have been moved while powered down or a program fails in anyway, it is recommended to run the reset command. This return the print-head to its home position and will reset any saved (and probably incorrect) information about the current position.

Movement

Move

The move command will move the print head. Use Adding + or - to will move to a relative position. - 5 steps = 1 mm for x and y axis - 156.25 steps = 1 mm for z axis

Move Command Examples:

• ./plotbot.py move_ x 50 mm will move the print head either to the left or the right so that it is 5 cm from the min(0) position.
• ./plotbot.py move z +50 steps will move the print head down 50 steps from the current position

Goto

The goto command will move the print head to named positions saved in the active profile. Built-in positions include min,mid, and max. Example

Profiles

Configuration profiles are maintained in the user's ~/.plotbot.json. Profiles can be modified with the set and profile commands.

Profile Command Examples :

• status Display the active profile
• set y top-of-page Saves the current y axis position as "top-of-page"
• profile --list Display available profiles from the users config file
• profile --load="dry-erase-board" Set the active profile to "dry-erase-board"
• profile --save="ballpoint-on-paper" Saves the current active profile as a new profile called "ballpoint-on-paper"
• profile --delete="experment-1" Deletes the "experiment-1" profile