ZX Spectrum, Soviet Style: A 44-IC Clone You Can Build

March 10, 2025 by Heidi Ulrich 6 Comments

If you’ve ever fancied building a ZX Spectrum clone without hunting down ancient ULAs or soldering your way through 60+ chips, [Alex J. Lowry] has just dropped an exciting build. He has recreated the Leningrad-1, a Soviet-built Spectrum clone from 1988, with a refreshingly low component count: 44 off-the-shelf ICs, as he wrote us. That’s less than many modern clones like the Superfo Harlequin, yet without resorting to programmable logic. All schematics, Gerbers, and KiCad files are open-source, listed at the bottom of [Alex]’ build log.

The original Leningrad-1 was designed by Sergey Zonov during the late Soviet era, when cloning Western tech was less about piracy and more about survival. Zonov’s design nailed a sweet spot between affordability and usability, with enough compatibility to run 90-95% of Spectrum software. [Alex]’ replica preserves that spirit, with a few 21st-century tweaks for builders: silkscreened component values, clever PCB stacking with nylon standoffs, and a DIY-friendly mechanical keyboard hack using transparent keycaps.

While Revision 0 still has some quirks – no SCART color output yet, occasional flickering borders with AY sound – [Alex] is planning for further improvements. Inspired to build your own? Read [Alex]’ full project log here.

Taming The Wobble: An Arduino Self-Balancing Bot

March 9, 2025 by Heidi Ulrich 8 Comments

Getting a robot to stand on two wheels without tipping over involves a challenging dance with the laws of physics. Self-balancing robots are a great way to get into control systems, sensor fusion, and embedded programming. This build by [mircemk] shows how to make one with just a few common components, an Arduino, and a bit of patience fine-tuning the PID controller.

At the heart of the bot is the MPU6050 – a combo accelerometer/gyroscope sensor that keeps track of tilt and movement. An Arduino Uno takes this data, runs it through a PID loop, and commands an L298N motor driver to adjust the speed and direction of two DC motors. The power comes from two Li-ion batteries feeding everything with enough juice to keep it upright. The rest of the magic lies in the tuning.

PID (Proportional-Integral-Derivative) control is what makes the robot stay balanced. Kp (proportional gain) determines how aggressively the motors respond to tilting. Kd (derivative gain) dampens oscillations, and Ki (integral gain) helps correct slow drifts. Set them wrong, and your bot either wobbles like a confused penguin or falls flat on its face. A good trick is to start with only Kp, then slowly add Kd and Ki until it stabilizes. Then don’t forget to calibrate your MPU6050; each sensor has unique offsets that need to be compensated in the code.

Once dialed in, the result is a robot that looks like it defies gravity. Whether you’re hacking it for fun, turning it into a segway-like ride, or using it as a learning tool, a balancing bot is a great way to sharpen your control system skills. For more inspiration, check out this earlier attempt from 2022, or these self-balancing robots (one with a little work) from a year before that. You can read up on [mircemk]’s project details here.

ice forming on surface with plus and minus pole

The Coolest Batteries You’ve Never Heard Of

March 9, 2025 by Heidi Ulrich 50 Comments

Imagine cooling your building with the same principle that kept Victorian-era icehouses stocked with lake-frozen blocks, but in modern form. That’s the idea behind ice batteries, a clever energy storage hack that’s been quietly slashing cooling costs across commercial buildings. The invention works by freezing water when energy is cheap, and using that stored cold later, they turn major power hogs (air conditioning, we’re looking at you) into more efficient, cost-effective systems.

Pioneers like Nostromo Energy and Ice Energy are refining the tech. Nostromo’s IceBrick modules pack 25 kWh of cooling capacity each, install on rooftops, and cost around $250 per kWh—about half the price of lithium-ion storage. Ice Energy’s Ice Bear 40 integrates with HVAC systems, shifting up to 95% of peak cooling demand to off-peak hours. And for homes, the Ice Bear 20 replaces traditional AC units while doubling as a thermal battery.

Unlike lithium-ion, ice batteries don’t degrade chemically – their water is endlessly reusable. Combining the technology with this hack, it’s even possible in environments where water is scarce. But the trade-off? They only store cooling energy. No frozen kilowatts for your lightbulbs, just an efficient way to handle the biggest energy drain in most buildings.

Could ice batteries help decentralize energy storage? They’re already proving their worth in high-demand areas like California and Texas. Read the full report here and let us know your thoughts in the comments.

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Closeup of a rackmounted custom HiFi setup

Rackmount All The Things, Hi-Fi Edition

March 6, 2025 by Heidi Ulrich 8 Comments

For those who love systems and structure, owning a 19-inch rack with just one slot filled is just not it. But what if the rest of your gear isn’t 19-inch? Well, then you go out and make it so, just like [Cal Bryant] did recently.

The goal was to consolidate multiple devices — DAC, input selector, streamer, and power routing — into a single 2U rackmount unit. His first attempts involved drilling 1U panels to attach gear with removable faceplates. That worked, but not all devices played nice. So his next step became a fully custom enclosure with CAD-modeled brackets and front panels.

OpenSCAD turned out to be a lifesaver, letting [Cal] design modular mounting solutions. Exporting proper circles for CNC turret punching however appeared to be a nightmare. It was FreeCAD to the rescue for post-processing. After some sanding and auto-shop painting, the final faceplate looked factory-made.

Custom switch boxes for power and audio routing keep things tidy, housing everything from USB to XLR inputs. A 4-pole switch even allows seamless swapping between his DAC and DJ controller, while UV-printed graphics bring the finishing touch to this project. For those looking to clean up their Hi-Fi setup (or just love modding for the sake of it), there’s a lot to learn from this build.

If buying a rack is not within your budget, you could start with well-known IKEA LACK furniture.

Dismanteled Hallicrafters radio on workbench

Shortwave Resurrection: A Sticky Switch Fix On A Hallicrafters

March 4, 2025 by Heidi Ulrich 10 Comments

Shortwave radio has a charm all its own: part history, part mystery, and a whole lot of tech nostalgia. The Hallicrafters S-53A is a prime example of mid-century engineering, but when you get your hands on one, chances are it won’t be in mint condition. Which was exactly the case for this restoration project by [Ken’s Lab], where the biggest challenge wasn’t fried capacitors or burned-out tubes, but a stubborn band selector switch that refused to budge.

What made it come to this point? The answer is: time, oxidation, and old-school metal tolerances. Instead of forcing it (and risking a very bad day), [Ken]’s repair involved careful disassembly, a strategic application of lubricant, and a bit of patience. As the switch started to free up, another pleasant surprise emerged: all the tubes were original Hallicrafters stock. A rare find, and a solid reason to get this radio working without unnecessary modifications. Because some day, owning a shortwave radio could be a good decision.

Once powered up, the receiver sprang to life, picking up shortwave stations loud and clear. Hallicrafters’ legendary durability proved itself once before, in this fix that we covered last year. It’s a reminder that sometimes, the best repairs aren’t about drastic changes, but small, well-placed fixes.

What golden oldie did you manage to fix up?

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Wake, Boot, Repeat: Remote OS Selection With GRUB And ESP

March 3, 2025 by Heidi Ulrich 14 Comments

What do you do when you need to choose an OS at boot but aren’t physically near your machine? [Dakhnod]’s inventive solution is a mix of GRUB, Wake-on-LAN (WOL), and a lightweight ESP8266 running a simple HTTP server. In the past, [dakhnod] already enlightened us with another smart ESP hack. This one’s a clever combination of network booting and remote control that opens up possibilities beyond the usual dual-boot selector.

At its core, the hack modifies GRUB to fetch its boot configuration over HTTP. The ESP8266 (or any low-power device) serves up a config file defining which OS should launch. The trick lies in adding a custom script that tells GRUB to source an external config:

#!/usr/bin/env cat 
net_dhcp 
source (http,destination_ip_or_host:destination_port)/grub/config

Since GRUB itself makes the HTTP request, the system needs a running web server. That could be a Raspberry Pi, another machine, or the ESP itself. From there, a WOL-enabled ESP button can wake the PC and set the boot parameters remotely.

Is it secure? Well, that depends on your network. An open, unauthenticated web server dishing out GRUB configs is risky, but within a controlled LAN or a VLAN-segmented environment, it’s an intriguing option. Automation possibilities are everywhere — imagine remotely booting test rigs, toggling between OS environments for debugging, or even setting up kiosk machines that reconfigure themselves based on external triggers.

For those looking to take it further, using configfile instead of source allows for more dynamic menu entries, although it won’t persist environment variables. You could even combine it with this RasPi hack to control the uptime of the HTTP server. The balance between convenience and security is yours to strike.

If you’ve got your own wild GRUB customisation, let’s hear it!

Behind The Lens: Tearing Down A Rare Soviet Zenit 19

February 23, 2025 by Heidi Ulrich 3 Comments

If you’re into Soviet-era gear with a techy twist, you’ll love this teardown of a rare Zenit 19 camera courtesy of [msylvain59]. Found broken on eBay (for a steal!), this 1982 made-in-USSR single-lens reflex camera isn’t the average Zenit. It features, for example, electronically controlled shutter timing – quite the upgrade from its manual siblings.

The not-so-minor issue that made this Zenit 19 come for cheap was a missing shutter blade. You’d say – one blade gone rogue! Is it lost in the camera’s guts, or snapped clean off? Add to that some oxidized battery contacts and a cracked viewfinder, and you’ve got proper fixer-upper material. But that’s where it gets intriguing: the camera houses a rare hybrid electronic module (PAPO 074), complete with epoxy-covered resistors. The shutter speed dial directly adjusts a set of resistors, sending precise signals to the shutter assembly: a neat blend of old-school mechanics and early electronics.

Now will it shutter, or stutter? With its vertical metal shutter – uncommon in Zenits – and separate light metering circuitry, this teardown offers a rare glimpse into Soviet engineering flair. Hungry for more? We’ve covered a Soviet-era computer and a radio in the past. If you’re more into analog camera teardowns, you might like this analog Pi upgrade attempt, or this bare minimum analog camera project.

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