Using 5V Programmable Logic Here In The 2020s

October 4, 2023 by 29 Comments

Do you speak GAL? [Peterzieba] does, and has pulled together a collection of documents and tools so that you can too. There’s a dividing line in electronic engineering education, between those who were taught about FPGAs, and those who weren’t. Blurring that line slightly is gate array logic (GAL). These devices were a preceursor to the FPGA, with a much simpler structure, and usually in those days UV-erasable in the same manner as an EPROM. And oddly enough, they, or at least their successor compatible parts, are still available, and as handy DIP devices that talk to 5 volt logic.

The guide goes into detail about the parts, the terminology surrounding them, and the CUPL language which raises a few memories for us. There are several possible workflows, including for those not faint of heart, the possibility of writing a fusemap by hand. We’re impressed by that one.

If these devices interest you, our colleague Bil Herd wrote a two-part guide (part one, and part two) which should answer your questions.

Thanks [Bjonnh] for the tip!

Featured image: “Commodore Amiga 1000 – sub board – Texas Instruments PAL16L8ACN-0126” by Raimond Spekking

One-String, One-Trick Pony Plays “the Lick”

October 4, 2023 by 14 Comments

Wouldn’t you love to be able to play a song on a stringed instrument even though you don’t have an iota of musical talent? That’s the idea behind Strumli, a single-string instrument built by [Factorem] that plays “the lick”. You know, the lick. Chances are, you’ve heard it somewhere before.

Essentially, it’s a pill-shaped bowl with a soundboard. A high-E guitar string is wound around bearings and tuned with a guitar tuner. The lengths of string between the bearings correspond to each note in the lick. Strum it in the right direction, and Bob’s your uncle.

So how the heck did [Factorem] come up with the proper string lengths needed to play the song? After a bit of fancy math involving the equation that represents the relationship between the measurable frequency of a vibrating string under tension and the tension itself, [Factorem] had the overall length of the string. Then it was a matter of finding the frequencies needed to play the lick, along with their corresponding lengths.

Since the string exerts about 80 pounds of tension across the 3D-printed soundboard, some serious internal bracing is required, which [Factorem] figured out in CAD program. All the files are available if you want to build your own. Be sure to check out the build/demo after the break.

Would you rather just build a little harp? Here’s the inspiration for Strumli — a single-string number with a full octave.

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2023 Halloween Hackfest: Flickering Pumpkin Pin Is Solidly Built

October 4, 2023 by 9 Comments

Now first of all, [Steph] grants that you can already take your pick of several LED pumpkin badges out there on IO. That’s not the point. The point is that this flickering pumpkin pin is nicely-built as well as being open source.

Even though it’s fully featured — it flickers, it’s wearable, and it’s lightweight — the build couldn’t be more simple. It’s fancy through-hole LEDs and a coin cell holder, plus a tack pin to stick it through your shirt. But the final result is quite elegant thanks to clever use of PCB layering.

The first version was to get all the layers right to let the light through and embellish the jack-o-lantern’s lines with manufacturer-applied silver solder, but as [Steph] points out, it looked ‘like something a disturbed child might carve into their desk in detention’. So [Steph] enlisted [Mx. Jack Nelson], who improved the artwork.

Pretty much every component does double duty here, including the tack pin — it serves as a switch because it can hold the battery in place. The battery’s edges reflect the glowing light quite nicely around the edge of the pin. And the LEDs beneath the battery prevent it from slipping out. You can see how it goes together in the video after the break.

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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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Hackaday Prize 2023: The Wildcard Finalists Are Here

October 4, 2023 by 5 Comments

We’re in the endgame now — there’s just about a month to go before the final results are announced for the 2023 Hackaday Prize, which means all of our finalists are in a mad rush to put the finishing touches on their respective projects. Today, ten more hackers are about to feel the heat as we announce our final group of finalists from the Save the World Wildcard round.

As finalists, each of these projects has been awarded $500 to help further their development. But perhaps more importantly, they are now officially in the running for one of the final six awards, which includes the Grand Prize of $50,000 and a residency at the Supplyframe DesignLab.

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Autonomous Wheelchair Lets Jetson Do The Driving

October 4, 2023 by 9 Comments

Compared to their manual counterparts, electric wheelchairs are far less demanding to operate, as the user doesn’t need to have upper body strength normally required to turn the wheels. But even a motorized wheelchair needs some kind of input from the user to control it, which still may pose a considerable challenge depending on the individual’s specific abilities.

Hoping to improve on the situation, [Kabilan KB] has developed a self-driving electric wheelchair that can navigate around obstacles by feeding the output of an Intel RealSense Depth Camera and LiDAR module into a Jetson Nano Developer Kit running OpenCV. To control the actual motors, the Jetson is connected to an Arduino which in turn is wired into a common L298N motor driver board.

As [Kabilan] explains on the NVIDIA Blog, he specifically chose off-the-shelf components and the most affordable electric wheelchair he could find to bring the total cost of the project as low as possible. An undergraduate from the Karunya Institute of Technology and Sciences in Coimbatore, India, he notes that this sort of assistive technology is usually only available to more affluent patients. With his cost-saving measures, he hopes to address that imbalance.

While automatic obstacle avoidance would already be a big help for many users, [Kabilan] imagines improved software taking things a step further. For example, a user could simply press a button to indicate which room of the house they want to move to, and the chair could drive itself there automatically. With increasingly powerful single-board computers and the state of open source self-driving technology steadily improving, it’s not hard to imagine a future where this kind of technology is commonplace.

Robotic Mic Swarm Helps Pull Voices Out Of Crowded Room Of Multiple Speakers

October 4, 2023 by 27 Comments

One of the persistent challenges in audio technology has been distinguishing individual voices in a room full of chatter. In virtual meeting settings, the moderator can simply hit the mute button to focus on a single speaker. When there’s multiple people making noise in the same room, though, there’s no easy way to isolate a desired voice from the rest. But what if we ‘mute’ out these other boisterous talkers with technology?

Enter the University of Washington’s research team, who have developed a groundbreaking method to address this very challenge. Their innovation? A smart speaker equipped with self-deploying microphones that can zone in on individual speech patterns and locations, thanks to some clever algorithms.

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