Author: Al Williams

4424 Articles

Fluid Simulation Does The Math

October 6, 2023 by 2 Comments

If you like math, you should enjoy [kynd’s] page about simulating fluid in p5.js. You might still enjoy the pretty colors and shapes if you aren’t into math. What’s scary is that the page promises to have as little math as possible, but there’s still quite a bit. Of course, we are sure you could go even deeper down the rabbit hole.

The algorithm’s core is a pair of 2D arrays representing cells that comprise the display area. One array holds the color of the cell, while another holds a velocity vector of the fluid in the cell. A vector, of course, has both a magnitude and a direction.

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Hackaday Podcast 239: Overclocking, Oscilloscopes, And Oh No! SMD Out Of Stock!

October 6, 2023 by 2 Comments

Elliot Williams and Al Williams got together again to discuss the best of Hackaday for a week, and you’re invited. This week, the guys were into the Raspberry Pi 5, CNC soldering, signal processing, and plasma cutting. There are dangerous power supplies and a custom 11-bit CPU.

Of course, there are a few Halloween projects that would fit in perfectly with the upcoming Halloween contest (the deadline is the end of this month; you still have time). OpenSCAD is about to get a lot faster, and a $20 oscilloscope might not be a toy after all. They wrap up by talking about Tom Nardi’s latest hardware conversion of DIP parts to SMD and how TVs were made behind the Iron Curtain.

Did you miss a story? Check out the links below. As always, tell us what you think about this episode in the comments!

Go ahead and download it!

Where to Follow Hackaday Podcast

Places to follow Hackaday podcasts:

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An SMD Capacitor Guide

October 5, 2023 by 5 Comments

For electronics, your knowledge probably follows a bit of a bell curve over time. When you start out, you know nothing. But you eventually learn a lot. Then you learn enough to be comfortable, and most of us don’t learn as much about new things unless we just happen to need it. Take SMD components. If you are just starting out, you might not know how to find the positive lead of an SMD capacitor. However, if you’ve been doing electronics for a long time, you might not have learned all the nuances of SMD. [Mr SolderFix] has been addressing this with a series of videos covering the basics of different SMD components, and this installment covers capacitors.

If you are dyed-in-the-wool with SMD, you might not get a lot out of the video, but we picked up a few tips, like using a zip tie for applying flux. The video starts with an examination of the different packages and markings. Then it moves on to soldering the components down.

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Lessons Learned While Building A DIY Pen Plotter

October 4, 2023 by 2 Comments

There was a time when plotters were the pinnacle of computer graphics output. While they aren’t as common as they used to be, there are some advantages to having a plotter. [Symon] wanted a plotter and decided to make one from scratch. Truthfully, he wants to build a CNC machine, so the plotter is just a stepping stone. In fact, some of it may be a little much for just a plotter. Other design choices have worked for the plotter, but don’t look like they will work well for the eventual CNC design.

As an example, the plotter uses 2020 extrusions and lead screws. An Arduino with a CNC shield provides the brains. GRBL, of course, runs on the Arduino, so the whole machine runs fine with normal G-code. This post will be especially interesting if you want to build a plotter or something similar. We especially like that it covers the design rationale for each choice made It is great to learn from others successes and, of course, their mistakes.

If you really want just a plotter, you don’t have to spend much. You can even go super minimal if you want.

LittleFS: The Emphasis Is On Little

October 4, 2023 by 15 Comments

It used to be that developing for microcontrollers was relatively relaxing. These days, even a cheap micro like the Raspberry Pi Pico has multiple cores, networking (for the W, at least), and file systems. Just like desktop computers. Sort of. I found out about the “sort of” part a few weeks ago when I decided to embark on a little historical project. I wanted a file system with a large file that emulates a disk drive. The Pico supports LittleFS, and I figured that would be the easy thing to do. Turns out the Little in LittleFS might be more literal than you think. On the plus side, I did manage to get things working, but it took a… well — dare I say hack? — to make it all work.

History

I’m an unabashed fan of the RCA 1802 CPU, which is, of course, distinctly retro. The problem is, I keep losing my old computers to moves, natural disasters, and whatnot. I’ve had several machines over the years, but they seem to be a favorite target of Murphy’s law for me. I do currently have a small piece of hardware called an Elf Membership Card (by [Lee Hart]), but it lacks fancy features like disk drives, and while it could be expanded, there’s something charming about its current small size. So that led me to repurpose a 6502 emulator for the KIM-1 to act like an 1802 instead. This is even less capable than the membership card, so it was sort of a toy. But I always thought I should upgrade the Arduino inside the emulator to a processor with more memory, and that’s what I did.

I started out with a Blackpill STM32F board and called the project 1802Black. The code is a little messy since it started out as [Oscar’s] KimUNO code, and then my updates layered with new updates. Also, for now, I shut off the hardware parts so it won’t use the KimUNO hardware — you only need a Blackpill (or a Pico, see below) and nothing else, although I may reenable the hardware integration later.

It wasn’t that hard to get it running with just more memory. Still, I wanted to run [Mike Riley’s] Elf/OS operating system and I also had a pair of Raspberry Pi Picos mocking me for not using them in a project yet. The chip has excellent Arduino board support. But what sealed the deal was noticing that you can partition the Pico’s flash drive to use some of it for your program and the rest for a file system. You can get other RP2040 dev boards with 16 MB of flash, which would let me have a nearly 15 MB “hard drive,” which would have been huge in the 1802’s day. Sounds simple. If it were, though, we wouldn’t be talking.

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Roll Your Own Servo

October 4, 2023 by 51 Comments

Usually, when you want a servo motor, you simply buy one already made. But if you need something unusual, you can turn any DC motor into a custom servo you can control just like [Dejan] did. You can watch a video of the process below.

The custom servo can tune the endpoints, the center point, and the sensitivity. It also can be set to handle continuous rotation. A 12-bit encoder tells the microcontroller where the motor is and the output drivers can handle over 3 A of motor current. The microprocessor is a tried-and-true ATmega328. [Dejan] wanted to make the board as small as possible, and we think 40 mm square isn’t bad at all. There is also a 3D printed gearbox and housing. Overall, a very well-done project.

The motor control uses a PID algorithm. Potentiometers set the end range and sensitivity. A push button allows resetting the center position. DIP switches control the mode. The video shows a computer and an RC controller setting the position of the motors.

We have, of course, seen many variations on this idea. We’ve also seen servos rebuilt for better performance.

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Passive Components Get Better

September 27, 2023 by 42 Comments

When you want to talk about cool new components, you are probably thinking about chips or, these days, even modules. Passive components like resistors, capacitors, and inductors are a solved problem, right? [Darshill Patel] begs to differ. There is still innovation happening in the passive market, and he highlights some of the recent advances.

There are thick-film resistors that don’t need lead, for example. There are also supercapacitor modules with very low ESR. For inductors, at least one manufacturer is moving away from traditional wire loops and using flat wire windings instead. These have a larger cross-section, which reduces unwanted resistance. In addition, it offers more cooling area for heat dissipation.

Of course, passive components have never been as simple as people think. Picking a capacitor’s value is only half the battle. You also need to consider the material to optimize how it works in your design. Wirewound resistors are also inductors unless you get special non-inductive ones that use special wiring techniques to cancel much of the parasitic inductance.

It shows that you can never stop learning about even the simplest components. We are still waiting to figure out what we want to do with a memristor. While tiny surface mount components are good for some assembly reasons, they also have helped reduce unwanted component effects.