PicoStepSeq Is Small But Perfectly Formed

August 20, 2022 by Jenny List 18 Comments

The Raspberry Pi Pico is what you might call the board of the moment, thanks to its combination of affordability, features, and continued availability during the component shortage. We have seen plenty of great projects using it, and the latest to float past is [todbot]’s PicoStepSeq, an extremely compact MIDI sequencer.

All the components are mounted on a PCB, with the sequencer’s eight steps selected by a row of buttons with integrated LEDs. The interface is via an SSD1306 OLED, and there is also a rotary encoder. Software comes courtesy of CircuitPython, and the output is delivered via a 3.5 mm TRS jack. Finally the whole is wrapped in a 3D printed enclosure.

The result is a sequencer that could almost be a product in its own right, and we think anyone whose interests lie in electronic music should find straightforward enough to build. All the files and information required to build your own can be found in the linked repository, and he’s placed a Tweet with a video online which we’ve embedded below the break.

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Batteries Get Tiny

August 20, 2022 by Al Williams 18 Comments

Steve Martin had a comedy routine that focused on the idea of “getting small.” That probably didn’t inspire the researchers at the Institute for Integrative Nanoscience when they set out to create a sub-square-millimeter microbattery. As you might expect, you won’t be starting your car with a battery the size of a grain of sand anytime soon, but these batteries do have a surprising capacity.

The key is creating what they call “micro-swiss rolls” where the electrodes are wrapped in a tiny cylinder. This isn’t a new idea. However, creating workable rolls at the scale where a grain of rice looks huge isn’t trivial.

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Deepdeck: Going Beyond The Macro Pad

August 20, 2022 by Jenny List 4 Comments

We’re used to the idea of a macropad, a small extension keyboard for your computer whose keys can be programmed to the functions of your choice. They can be made in many ways, but they all follow a similar functionality. Deepdeck from [Nick Velasquez] is another matter, an attempt to make a macropad with functionality that goes way beyond simply pressing keys.

At its heart is an ESP32 module, and it makes full use of both Bluetooth and wireless networking capabilities. It can use Bluetooth when connecting to the host computer, and the wireless connection hosts both the configuration interface via a web server and an Internet connection from which it derives those special powers. This is a macropad with programmable keys just like all the others, but it also has the ability to connect to online APIs programmed by the user. This allows it to automate complex queries involving other sources into a keypress, which gives it many more possibilities.

A tool such as this one is one of those things which requires a bit of thought as to exactly how it might be used. A normal API connected device might display the weather on a screen for instance, but how often does one need to type the weather forecast? However we can see that this extra online dimension will find as yet unseen applications, and we look forward to the idea being taken up with other macropads.

Building A Spot Welder From 500 Junk Capacitors

August 20, 2022 by Dave Rowntree 5 Comments

[Kasyan TV] over on YouTube was given a pile of spare parts in reasonably large quantities, some of which were useful and allocated to specific projects, but given the given the kind of electronics they’re interested in, they couldn’t find a use for a bag of 500 or so low specification 470uF capacitors. These were not low ESR types, nor high capacitance, so unsuitable for power supply use individually. But, what about stacking them all in parallel? (video, embedded below) After a few quick calculations [Kasyan] determined that the total capacitance of all 500 should be around 0.23 Farads with an ESR of around 0.4 to 0.5 mΩ at 16V and packing a theoretical energy total of about 30 joules. That is enough to pack a punch in the right situation.

A PCB was constructed to wire 168 of the little cans in parallel, with hefty wide traces, reinforced with multiple strands of 1.8mm diameter copper wire and a big thick layer of solder over the top. Three such PCBs were wired in parallel with the same copper wire, in order to keep the total resistance as low as possible. Such a thing has a few practical uses, since the super low measured ESR of 0.6mΩ and large capacitance makes it ideal for smoothing power supplies in many applications, but could it be used to make a spot welder? Well, yes and no. When combined with one of the those cheap Chinese ‘spot welder’ controllers, it does indeed produce some welds on a LiPo cell with a thin nickel plated battery strip, but blows straight through it with little penetration. [Kasyan] found that the capacitor bank could be used in parallel with a decent LiPo cell giving a potentially ideal combination — a huge initial punch from the capacitors to blow through the strip and get the weld started and the LiPo following through with a lower (but still huge) current for a little longer to assist with the penetration into the battery terminal, finishing off the weld.

[Kaysan] goes into some measurements of the peak current delivery and the profile thereof, showing that even a pile of pretty mundane parts can, with a little care, be turned into something useful. How does such an assembly compare with a single supercapacitor? We talked about supercaps and LiPo batteries a little while ago, which was an interesting discussion, and in case you’re still interested, graphene-based hybrid supercapacitors are a thing too!

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2022 Cyberdeck Contest: Extruded Rig Exudes Coolness

August 20, 2022 by Kristina Panos No comments

When we came up with the cyberdeck contest, we figured we would see all kinds of builds, and so far, y’all haven’t disappointed us. Take for instance this tidy but post-apocalyptic build by [facelessloser]. It has that “I used what I could find among the rubble” appeal, yet it looks so clean. Now why is that?

It must be partially because of the frame, which is 2020 aluminium extrusion. Now as you can see, this cyberdeck is based on the Raspberry Pi 400, which combines the power of a Pi 4 with a chiclet keyboard and the retro feel of the all-in-one computers of yore.

But this cyberdeck build really began because [facelessloser] had a 7″ HDMI screen kicking around for a while and finally settled on this design. The screen connects to the extrusion rail with a pair of custom-printed brackets, and is prevented from sliding back and forth with more plastic, including a nice enclosure that holds the speaker, amp board, headphone jack, and USB-C port.

Since the screen has no sound of its own, [facelessloser] added a 3 W amplifier board and a speaker for playing chiptunes and other kinds of electronic noise that provide just the right ambiance. We absolutely love the printed mesh cover on the back made of hexagons — not only does it look nice, it’s a functional, minimal, breathable solution to corralling the cabling while simultaneously showing off the internals. You can find a bit more detail and some extra build pictures over on the blog post, and be sure to check out the video after the break to see how [facelessloser] has implemented this cyberdeck into their bench, and stick around for a tour of the build.

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Dream Projects Face Reality

August 20, 2022 by Elliot Williams 26 Comments

Do you ever get a project stuck in your mind? An idea so good you just keep thinking about it? Going over iterations and options and pros and cons in the back of your mind, or maybe on paper, but having not yet subjected it to the hard work of pulling it into reality? I’ve had one of those lurking around for the last couple weeks, and it’s time for me to get building.

And I’ve got to get started soon, because it’s rare that any project makes the leap from thought to reality unscathed, and when I hold on to the in-thought project too long, I become far too fond of some of the details and nuances that just might not make the cut, or might get in the way of getting a first pass finished. When I really like a (theoretical) solution to a (theoretical) problem, I’ll try to make it work a lot longer than I should, and I can tell I’m getting attached to this one now.

The only cure to this illness is to get prototyping. When the rubber hits the road, and the bolts are tightened, either the solution is a good one or it’s not, and no amount of dreaming is going to change that. Building is a great antidote to the siren song of a dream project. Although it feels now like I don’t want the fantasy to have to adapt to reality, as it inevitably will, I know that getting something working feels a lot better. And it frees me up to start dreaming on the next project… To the workshop!

Z80 Single-Board Computer Looks Like It Could Have Been A Killer Product

August 20, 2022 by Dan Maloney 30 Comments

Most retrocomputer builds seem to focus on either restoring old machines or rebuilding them from scratch. Either way, the goal is to get as close as possible to the original machine, and while we certainly respect those builds, there are other ways to celebrate the computers of yesterday, as this Z80 single-board computer nicely demonstrates.

[Ivan Farafontov]’s SBC is sort of a “Z80 that never was” build, one that would almost have been possible back in the heyday of 8-bit computing, and would have made quite a splash if it had. Most of the peripheral chips are from Zilog and would have been found in many of the Z80 machines of the day, like the TRS-80 and ZX Spectrum. Where it goes off the old-school path is with the video section, which uses an Atmel CPLD chip and a dual-port RAM to drive a VGA monitor. It still looks the part, though, with a 256×192 pixel, 16-color display. The compact video section helps keep the overall footprint of this machine pretty small, at least by the standards of the old machines. The machine is barely larger than its custom keyboard, which is populated with mechanical switches and really nice-looking custom keycaps, and everything fits into a 3D-printed case.

The demo that starts at the 4:30 mark of the video below will be a nostalgia storm for a lot of readers, starting as it does with a version of Boulder Dash that [Ivan] wrote from scratch, along with the tile editor he used to create the sprites for the game. All the design files and code are available if you want to build your own, of course. We recently featured another Z80 that never was, but [Ivan]’s machine really makes a statement with its compact size and its capabilities.

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