BrachioGraph#
The world’s cheapest, simplest possible pen-plotter.
BrachioGraph - arm-writer - is an easy-to-build pen-plotter, driven by a library of simple Python applications.
BrachioGraph plots cheerful, low-fi drawings, and can produce robotic sketches using a variety of drawing implements.
A BrachioGraph can be built for about €15 in an hour or so, using a Raspberry Pi computer, hobby servo motors and household items. The BrachioGraph library is published on GitHub and includes simple Python code to drive the plotter and vectorise bit-map images.
In this documentation#
Tutorial: Wire up the plotter • Start up the BrachioGraph • Start plotting • Improve the output • Apply more sophisticated calibration
Hardware and design: Overview • Working with limitations • Visualise servo behaviour • Alternative building techniques • Build a Pantograph
Mathematics: Geometric calculation • Geometric visualisation
Working with the plotter: Raspberry Pi Zero quick-start guide • Plotter module reference • Run a virtual plotter
Python turtle plotting: Visualise a plotter using Turtle graphics • Turtle plotter reference
Image processing: Vectorise images • linedraw.py reference
Development: Build the documentation • Run automated tests
How this documentation is organised#
This documentation uses the Diátaxis documentation structure.
The Tutorial takes you step-by-step through the process of building the machine, installing the software and making your first drawings.
How-to guides assume you have basic familiarity with the BrachioGraph. They go deeper into problems and explore things you can do with the system.
Reference provides a guide to APIs, key classes and functions.
Explanation includes topic overviews, background and context and detailed discussion.
From bitmap to plot via vectorisation#
Community contributions#
BrachioGraph is a hobby project, and I have very limited time to work on it. It means that I don’t have the capacity to answer the many questions I get, or even to give due consideration the numerous offers of improvement.
Other people in the open-source community have created their own resources for working with BrachioGraph.
brachio.me: vectorise images with a web version of
linedraw3D printed plotter components, including arms and stand-offs
Video: Building a BrachioGraph