Raspberry Pi enthusiasts or electronic hobbyists looking to build an affordable pen plotter may be interested in the BrachioGraph. An easy-to-build pen-plotter, driven by a library of simple Python applications. This project is perfect for those who enjoy DIY electronics and want to explore the capabilities of the Raspberry Pi in a creative and educational way. To be able to build your pen plotter you will need:
– two sticks or pieces of stiff card
– a pencil or ballpoint pen
– a clothes-peg
– 3 servo motors
– a Raspberry Pi, to drive the servos and run the custom code
Building the BrachioGraph
The BrachioGraph is designed to be the “cheapest, simplest possible pen-plotter,” making it accessible to a wide range of users, from beginners to advanced hobbyists. The materials required are minimal and inexpensive, ensuring that anyone can get started without a significant investment. The two sticks or pieces of stiff card serve as the arms of the plotter, while the pencil or ballpoint pen acts as the drawing instrument. The clothes-peg is used to hold the pen in place, and the three servo motors provide the necessary movement to create drawings.
The Raspberry Pi is the brain of the operation, driving the servos and running the custom code that brings the BrachioGraph to life. Full instructions on how to build your BrachioGraph can be found on the official website, which provides a step-by-step guide to assembling the plotter. The website also explains the mathematics behind the pen plotter, offering insights into the geometry and algorithms that make the BrachioGraph function. Additionally, it provides details on alternative designs and materials that can be used to create a variety of different configurations, allowing users to customize their plotter to suit their needs.
Software and Applications
The software for the BrachioGraph is a collection of Python scripts that control the plotter’s movements and enable it to draw images. The main components of the software are:
– brachiograph.py to draw images using the servos
– linedraw.py to vectorise bit-map images
– turtle_draw.py to help visualise the drawing area of the plotter
– pulse_widths.ipynb, a Jupyter notebook to visualise the relationship between pulse-widths and servo angles
– pantograph.py to drive an alternative plotter design
The brachiograph.py script is the core of the software, responsible for translating image data into servo movements that produce drawings. The linedraw.py script is used to convert bitmap images into vector graphics, which can then be plotted by the BrachioGraph. This allows users to create detailed and precise drawings from digital images.
The turtle_draw.py script is a useful tool for visualizing the drawing area of the plotter, helping users to understand the limits and capabilities of their device. The pulse_widths.ipynb Jupyter notebook provides a visual representation of the relationship between pulse-widths and servo angles, offering a deeper understanding of how the servos are controlled. Finally, the pantograph.py script enables an alternative plotter design, giving users the flexibility to experiment with different configurations and expand the functionality of their BrachioGraph.
The BrachioGraph project is an excellent way to learn about robotics, programming, and electronics. It offers a hands-on experience that combines creativity with technical skills, making it a rewarding and educational endeavor. Whether you are a seasoned maker or a newcomer to the world of DIY electronics, the BrachioGraph provides a fun and engaging way to explore the possibilities of the Raspberry Pi.
Source: BG
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