Minimal UART Computer

March 17, 2021 by Chris Lott 25 Comments

[Carsten] spent over a year developing a small CPU system, implementing his own minimalist instruction set entirely in TTL logic. The system uses a serial terminal interface for all I/O, hence the term UART in the title. [Carsten] began building this computer on multiple breadboards, which quickly got out of hand.

He moved the design over to a PCB, but he was still restless. This latest revision replaces EEPROM with cheaper and easier to use CMOS Flash chips, and the OS gains a small file system manager. As he says in the video, his enemy is feature creep.

In addition to designing this CPU project, [Carsten] built an assembler and wrote a substantial operating system and various demo programs and games. He not only learned KiCAD to make this board, but also taught himself to use an auto-router. The KiCAD design, Gerbers, and BOM are all provided in his repository above. ROM images and source code are provided, as well as a Windows cross-assembler. But wait – there’s more. He also wrote a cycle exact emulator of the CPU, which, as he rightfully brags, comes in at under 250 lines of C++ code. This whole project is an amazing undertaking and represents a lot of good work. We hope he will eventually release the assembler project as well, in case others want to take on the challenge of building it to run under Linux or MacOS. Despite this, the documentation of the Minimal UART Computer is excellent.

[Carsten] claims the project has finally passed the finish line of his design requirements, but we wonder, will he really stop here? Do check out his YouTube channel for further informative videos. And thanks to [Bruce] for sending in the tip.

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A Big Set Of Logic Gates For Teaching The Basics

January 24, 2021 by Lewin Day 22 Comments

Teaching students about logic gates is often done in two parts, once on the whiteboard for the theory, and again on the breadboard for the practice. [shurik179] wasn’t a fan of the abstraction between easy-to-understand symbols on the whiteboard, and small IC packages full of many gates in reality. Instead, he built a set of real-world logic gates that can be wired together as a teaching tool.

Each “gate’ consists of a PCB roughly the size of a business card that features LEDs to indicate the state of its inputs and outputs, and a silkscreen indicating the name and symbol of the gate in question. There’s also a master PCB, which features three seed values, A, B, and C, to feed into the system. Students can set these values to 1 or 0, and feed them into the gates, which are wired together with 3-conductor servo cables, and observe the input on the built-in LEDs.

It’s a great way to demonstrate logic gates in the classroom. The design also allows the PCBs to be flipped over to show the actual electronic components responsible for implementing the logic, serving as a great bridge towards better understanding of real electronic design. Of course, it’s not the only way to learn – even Fallout 4 has a fully fledged logic toolkit these days!

Electric Puzzle Board Lets You Assemble Circuits With Ease

January 6, 2021 by Lewin Day 20 Comments

Many hackers learned about electronics over the years with home experimenter kits from Radio Shack and its ilk. Eschewing soldering for easier screw or spring based connections, they let the inexperienced build circuits with a minimum of fuss, teaching them the arcane ways of the electron along the way. [victorqedu] has put a modern spin on the form, with his Electric Puzzle Game.

The build consists of a series of 3D printed blocks, each containing a particular electronic component or module. The blocks can be joined together to form circuits, with magnets in the blocks mating with screws in the motherboard to hold everything together and make electrical contact between the parts. It’s a project that requires a significant amount of 3D printing and upfront assembly to build, but it makes assembling circuits a cinch.

The variety of circuits that can be built is impressive. [victorqedu] shows off everything from simple LED and switch arrangements to touch sensors and even a low-powered “Tesla coil”. We imagine playing with the blocks and snapping circuits into place would be great fun. We’ve seen other unconventional approaches before, too – such as building squishy circuits for educational purposes. Video after the break.

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Quick And Simple Milliohmmeter

November 4, 2020 by Chris Lott 12 Comments

User [mircemk] presents his “MiliOhm Meter” project which you can build with an Arduino, a handful of common parts from your lab, and a cigar box. It doesn’t get much simpler than this, folks. While this is something you won’t be getting calibrated with NIST traceability, it looks like a fun and quick project that’s more than suited for hobbyist measurements. It’s not only easy to build, the Arduino sketch is less than thirty lines of code. This is a great learning project, plus you get something useful for your lab when its finished.

We like the creative use of colored tape instead of paint on the project’s box. If this style suits you, [mircemk] has published several other similar lab instrument projects on his Hackaday.io page, including a frequency meter, an audio spectrum analyzer, and an auto-ranging capacitance meter to name a few. You might recognize him from some other projects we’ve featured, such as the crazy kinematic arms that set a clock’s hands every minute.

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Developing An Open Source Electronics Trainer

October 7, 2020 by Tom Nardi 25 Comments

It’s a safe bet that most Hackaday reader’s interest in electronics started at a young age, and that their early forays into the world of hardware hacking likely involved some form of “playground” kit. As long as you didn’t lose any of the components, these kits promised the user that hundreds of possible projects were just a few jumper wires away. Extra points awarded for when you decide to toss away the manual and fly solo.

While there’s still no shortage of such products on the market, [Josh Kittle] felt the concept could do with a freshening up. His open hardware “Microcontroller Trainer” harkens back to those old multi-kits, but adds in the sort of high-tech gadgetry that makes the modern DIY world go round.

It’s still got the traditional layout: a center mounted breadboard surrounded by an array of LEDs, a handful of buttons, and a pair of potentiometers. But there’s also sockets for the Raspberry Pi, ESP8266, ESP32, and Arduino. Plus a few of their most popular friends to keep them company: a .96″ OLED, 2.4″ Touch TFT, and a BC05 Bluetooth module.

Originally [Josh] created this design to help clean up his own workspace, figuring he could just put his most used components on a single compact board. But as you might expect, others expressed interest in the concept. Now he’s producing them as kits, and even working his way towards a third hardware revision that adds features such as an integrated 18650 battery for portable use.

While electronics kits that have you build a functional device are a great way to learn the ropes, we’re always glad to see fresh takes on the classic electronic “playground” concept.

Raspberry Pi Cluster Shows You The Ropes

April 24, 2020 by Bryan Cockfield 28 Comments

Raspberry Pi clusters are a common enough project, but a lot of the builds we see focus on the hardware side of the cluster. Once it’s up and running, though, what comes next? Raspberry Pis aren’t very powerful devices, but they can still be a great project for learning how to interact with a cluster of computers or for experimental test setups. In this project from [Dino], four Pis are networked together and then loaded with a basic set of software for cluster computing.

The first thing to set up, after the hardware and OS, is the network configuration. Each Pi needs a static IP in order to communicate properly. In this case, [Dino] makes extensive use of SSH. From there, he gets to work installing Prometheus and Grafana to use as monitoring software which can track system resources and operating temperature. After that, the final step is to install Ansible which is monitoring software specifically meant for clusters, which allows all of the computers to be administered more as a unit than as four separate devices.

This was only part 1 of [Dino]’s dive into cluster computing, and we hope there’s more to come. There’s a lot to do with a computer cluster, and once you learn the ropes with a Raspberry Pi setup like this it will be a lot easier to move on to a more powerful (and expensive) setup that can power through some serious work.

Gain An Understanding Of Injection Molding’s Design Gotchas

April 19, 2020 by Donald Papp 11 Comments

When it comes to manufacturing, sheet metal and injection molding make the world go ’round. As a manufacturing method, injection molding has its own range of unique design issues and gotchas that are better to be aware of than not. To help with this awareness, [studiored] has a series of blog posts describing injection molding design issues, presented from the perspective of how to avoid and address them.

Design of screw bosses demonstrating conflict between molder’s guidelines and vendor’s recommendations. Compromising between both is a science and an art.

Because injection molding involves heat, warp is one issue to be aware of and its principles will probably be familiar to anyone with nitty-gritty experience in 3D printing. Sink marks are also an issue that comes down to differential cooling causing problems, and can ruin a smooth and glossy finish. Both of these play a role in how best to design bosses.

Minimizing and simplifying undercuts (similar to overhangs in 3D printer parlance) is a bit more in-depth, because even a single undercut means much more complex tooling for the mold. Finally, because injection molding depends on reliably molding, cooling, and ejecting parts, designing parts with draft (a slight angle to aid part removal) can be a fact of life.

[studiored] seems to have been working overtime on sharing tips for product design and manufacture on their blog, so it’s worth keeping an eye on it for more additions. We mentioned earlier that much of the manufacturing world revolves around injection molding and sheet metal, so to round out your knowledge we published a primer on everything you need to know about the art and science of bending sheet metal. With a working knowledge of the kinds of design issues that affect these two common manufacturing methods, you’ll have a solid foundation for any forays into either world.