This blog post details a modern approach to building a functional replica of a Sinclair ZX80 or ZX81 home computer. The author advocates using readily available components like an Arduino Nano, a PS/2 keyboard, and a composite video output for a simplified build process, bypassing the complexities of sourcing obsolete parts. The project utilizes a pre-written ROM image and emulates the Z80 CPU via the Arduino, allowing for a relatively straightforward construction and operation of a classic machine. The author provides complete instructions, including schematics, Arduino code, and links to necessary resources, enabling enthusiasts to recreate this iconic piece of computing history.
This comprehensive guide, titled "How to build your own ZX80/ZX81 (2019)," meticulously details the process of constructing a replica of the iconic Sinclair ZX80 or ZX81 home computer. The author begins by emphasizing the project's suitability for both novice and experienced electronics enthusiasts, offering a pathway to understanding fundamental computer architecture while indulging in a bit of nostalgic computing.
The guide outlines two distinct approaches to building these retro machines: The first involves utilizing readily available, modern PCB (Printed Circuit Board) designs and readily sourced components. This approach simplifies the build process, reducing the complexity of sourcing obsolete parts. The second method embraces a more traditional approach, mimicking the original construction techniques by using stripboard or veroboard, offering a more authentic, albeit slightly more challenging, building experience. The guide meticulously details both methods, providing clear instructions and visual aids for each step.
The author provides a thorough explanation of the necessary components, including the Z80 microprocessor, the heart of both machines, and the different memory chips required. The function of each component is carefully explained, helping the builder understand the role it plays in the overall system. Furthermore, the guide provides insights into sourcing these components, directing readers towards reputable suppliers or suggesting suitable replacements where original parts might be difficult to obtain.
The construction process is broken down into manageable steps, each accompanied by clear photographs and diagrams. These visuals illustrate the correct placement of components on the PCB or veroboard, ensuring that even those new to electronics assembly can follow along with confidence. Specific instructions are given for soldering the components, emphasizing proper techniques for creating reliable connections.
Beyond the hardware assembly, the guide delves into the software aspect of these retro machines. It describes the process of loading programs into the limited memory, either through manual entry or using more modern methods like cassette interfaces or even ROM chips. The author explains the basic principles of the ZX80/ZX81's operation, providing a fundamental understanding of how the system functions.
The guide further explores options for enhancing the basic build, such as expanding the memory or adding a more robust power supply. These enhancements provide opportunities for customization and improvement beyond the initial construction. Troubleshooting tips are also included, offering solutions to common problems encountered during the build process. The author concludes by showcasing a finished, functioning ZX80/ZX81, demonstrating the successful culmination of the project and inspiring readers to embark on their own retro computing journey. This comprehensive resource makes the seemingly daunting task of building a vintage computer accessible to a wide audience, fostering an appreciation for the ingenuity of early computer design.
Summary of Comments ( 10 )
https://news.ycombinator.com/item?id=42808038
Commenters on Hacker News largely express nostalgia for the ZX80/81 and similar early home computers, recalling fond memories of learning to program on them and the ingenuity required to overcome their limitations. Several commenters discuss their experiences building replicas or emulating these machines, sharing tips on sourcing components and alternative approaches like using Raspberry Pis. Some debate the historical accuracy of classifying the ZX81 as a "full computer," with others pointing out its significance in democratizing access to computing. A few commenters express interest in the simplicity and elegance of the design compared to modern computers, while others share links to similar retro-computing projects and resources. The overall sentiment is one of appreciation for the ingenuity and historical importance of these early machines.
The Hacker News post linked, titled "How to build your own ZX80/ZX81 (2019)", has several comments discussing various aspects of the original ZX80/ZX81 computers, building modern replicas, and the nostalgic appeal of these early machines.
Several commenters reminisce about their experiences with the ZX80/81, sharing personal anecdotes about learning to program on them, the limitations of the hardware (especially the membrane keyboard and the tendency for the picture to vanish when typing), and the excitement of getting one as a child. One user describes how they wrote a simple program to print their name, showcasing the impact these machines had on introducing people to programming.
The discussion also delves into technical details, comparing the ZX80 to the ZX81, and noting the improvements made in the later model. One commenter explains the differences between the two models and notes that the American version of the ZX81 was called the TS1000/TS1500. Others discuss the limitations of the original ROM and the availability of third-party ROMs that provided enhanced functionality. A recurring theme in these technical discussions is the simplicity and elegance of the hardware design, making it a great learning platform.
Several comments explore the practicality of building a replica today, considering the availability of modern alternatives like the Raspberry Pi. Some users argue that building a replica offers a unique learning experience and a deeper appreciation for the original hardware, while others suggest that emulating the ZX80/81 on modern hardware is a more practical approach. One commenter mentions a project called the "ZX Spectrum Next" which aims to be a "ZX Spectrum for the 21st Century," bridging the gap between the classic machine and modern hardware capabilities. Another points to a modern recreation of the ZX81 with a real membrane keyboard being sold on Etsy.
A few comments also touch on the broader historical context of the ZX80/81, its role in the home computer revolution, and its influence on subsequent generations of computers and programmers. The affordability and accessibility of these machines are highlighted as key factors in their popularity and impact.
Overall, the comments paint a picture of fond remembrance and technical appreciation for the ZX80/81, showcasing its importance in the history of personal computing and its enduring appeal for enthusiasts and hobbyists. The discussion also reflects the ongoing interest in retrocomputing and the desire to revisit and learn from these early machines.