Low Cost Oscilloscope Gets Low Cost Upgrades

April 20, 2025 by Bryan Cockfield 51 Comments

Entry-level oscilloscopes are a great way to get some low-cost instrumentation on a test bench, whether it’s for a garage lab or a schoolroom. But the cheapest ones are often cheap for a reason, and even though they work well for the price they won’t stand up to more advanced equipment. But missing features don’t have to stay missing forever, as it’s possible to augment them to get some of these features. [Tommy’s] project shows you one way to make a silk purse from a sow’s ear, at least as it relates to oscilloscopes.

Most of the problem with these lower-cost tools is their low precision due to fewer bits of analog-digital conversion. They also tend to be quite noisy, further lowering the quality of the oscilloscope. [Tommy] is focusing his efforts on the DSO138-mini, an oscilloscope with a bandwidth of 100 kHz and an effective resolution of 10 bits. The first step is to add an anti-aliasing filter to the input, which is essentially a low-pass filter that removes high frequency components of the signal, which could cause a problem due to the lower resolution of the device. After that, digital post-processing is done on the output, which removes noise caused by the system’s power supply, among other things, and essentially acts as a second low-pass filter.

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A Pi-Based LiDAR Scanner

April 18, 2025 by Bryan Cockfield 30 Comments

Although there are plenty of methods for effectively imaging a 3D space, LIDAR is widely regarded as one of the most effective methods. These systems use a rapid succession of laser pulses over a wide area to create an accurate 3D map. Early LIDAR systems were cumbersome and expensive but as the march of time continues on, these systems have become much more accessible to the average person. So much so that you can quickly attach one to a Raspberry Pi and perform LiDAR imaging for a very reasonable cost.

This software suite is a custom serial driver and scanning system for the Raspberry Pi, designed to work with LDRobot LIDAR modules like the LD06, LD19, and STL27L. Although still in active development, it offers an impressive set of features: real-time 2D visualizations, vertex color extraction, generation of 360-degree panoramic maps using fisheye camera images, and export capabilities for integration with other tools. The hardware setup includes a stepper motor for quick full-area scanning, and power options that include either a USB battery bank or a pair of 18650 lithium cells—making the system portable and self-contained during scans.

LIDAR systems are quickly becoming a dominant player for anything needing to map out or navigate a complex 3D space, from self-driving cars to small Arduino-powered robots. The capabilities a system like this brings are substantial for a reasonable cost, and we expect to see more LiDAR modules in other hardware as the technology matures further.

Thanks to [Dirk] for the tip!

Presence Detection Augments 1930s Home

April 18, 2025 by Bryan Cockfield 18 Comments

It can be jarring to see various sensors, smart switches, cameras, and other technology in a house built in the 1930s, like [Chris]’s was. But he still wanted presence detection so as to not stub any toes in the dark. The result is a sensor that blends in with the home’s aesthetics a bit better than anything you’re likely to find at the Big Box electronics store.

For the presence detection sensors, [Chris] chose to go with 24 GHz mmwave radar modules that, unlike infrared sensors, can detect if a human is in an area even if they are incredibly still. Paired with the diminutive ESP32-S2 Mini, each pair takes up very little real estate on a wall.

Although he doesn’t have a 3D printer to really pare down the size of the enclosure to the maximum, he found pre-made enclosures instead that are fairly inconspicuous on the wall. Another design goal here was to make sure that everything was powered so he wouldn’t have to perpetually change batteries, so a small wire leads from the prototype unit as well.

The radar module and ESP pair are set up with some code to get them running in Home Assistant, which [Chris] has provided on the project’s page. With everything up and running he has a module that can control lights without completely changing the aesthetic or behavior of his home. If you’re still using other presence sensors and are new to millimeter wave radar, take a look at this project for a good guide on getting started with this fairly new technology.

Windows On ARM On Arm

April 10, 2025 by Bryan Cockfield 12 Comments

While some companies like Apple have gone all-in on the ARM architecture, others are more hesitant to dive into the deep end. For example, Microsoft remains heavily invested in the x86 architecture and although it does have some ARM offerings, a lot of them feel a bit half-baked. So you might question why someone like [Gustave] has spent so much time getting Windows to run on unusual ARM platforms. But we don’t need much of a reason to do something off-the-wall like that around these parts, so take a look at his efforts to get Windows for ARM running on a smartwatch.

The smartwatch in question here is a Pixel Watch 3, which normally runs a closed-source Android implementation called Wear OS. The bootloader can be unlocked, so [Gustave] took that approach to implement a few clever workarounds to get Windows to boot including adding UEFI to the watch. During the process Google updated these devices to Android 15, though, which broke some of these workarounds. The solution at that point was to fake a kernel header and re-implement UEFI and then load Windows (technically Windows PE) onto the watch.

Although this project was released on April 1, and is by [Gustave]’s own admission fairly ridiculous and not something he actually recommends anyone do, he does claim that it’s real and provides everything needed for others to run Windows on their smartwatches if they want to. Perhaps one of our readers will be brave enough to reproduce the results and post about it in the comments. In the meantime, there are a few more open options for smartwatches available if you’re looking for something to tinker with instead.

Thanks to [Ruhan] for the tip!

A New Mechanical Keyboard For An Old Computer

April 10, 2025 by Bryan Cockfield 9 Comments

As computers age, a dedicated few work towards keeping some of the more interesting ones running. This is often a losing battle of sorts, as the relentless march of time comes for us all, human and machine alike. So as fewer and fewer of these machines remain new methods are needed to keep them running as best they can. [CallousCoder] demonstrates a way of building up a new keyboard for a Commodore 64 which both preserves the original look and feel of the retro computer but also adds some modern touches.

One of the main design differences between many computers of the 80s and modern computers is that the keyboard was often built in to the case of the computer itself. For this project, that means a custom 3D printed plate that can attach to the points where the original keyboard would have been mounted inside the case of the Commodore. [CallousCoder] is using a print from [Wolfgang] to get this done, and with the plate printed and a PCB for the keys it was time to start soldering. The keyboard uses modern switches and assembles like most modern keyboards do, with the exception of the unique layout for some of the C64 keys including a latching shift key, is fairly recognizable for anyone who has put together a mechanical keyboard before.

[CallousCoder] is using the original keycaps from a Commodore 64, so there is an additional step of adding a small adapter between the new switches and the old keycaps. But with that done and some amount of configuring, he has a modern keyboard that looks like the original. If you’re more a fan of the original hardware, though, you can always take an original C64 keyboard and convert it to USB to use it on your modern machines instead.

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Self-Hosting A Cluster On Old Phones

April 9, 2025 by Bryan Cockfield 34 Comments

The phones most of us carry around in our pockets every day hold a surprising amount of computing power. It’s somewhat taken for granted now that we can get broadband in our hands in most places; so much so that when one of these devices has reached the end of its life it’s often just tossed in a junk drawer even though its capabilities would have been miraculous only 20 years ago. But those old phones can still be put to good use though, and [Denys] puts a few of them back to work running a computing cluster.

Perhaps the most significant flaw of smartphones, though, is that most of them are locked down so much by their manufacturers that it’s impossible to load new operating systems on them. For this project you’ll need to be lucky enough (or informed enough) to have a phone with an unlockable bootloader so that a smartphone-oriented Linux distribution called postmarketOS can be installed. With this nearly full-fledged Linux distribution to work from, the phones can be accessed by ssh and then used to run Kubernetes for the computing cluster. [Denys] has three phones in his cluster that run a few self-hosted services for him.

[Denys] also points out in his guide that having a phone that can run postmarketOS might save some money when compared to buying a Raspberry Pi to run the same service, and the phones themselves can often be more powerful as well. This is actually something that a few others have noted in the past as well. He’s gone into a considerable amount of detail on how to set this up, so if you have a few old smartphones gathering dust, or even those with broken screens or other physical problems where the underlying computing resources are still usable, it’s a great way to put these machines back to work.

Thanks to [mastro Gippo] for the tip!

Automatically Crack Safes With This Autodialer

March 30, 2025 by Bryan Cockfield 13 Comments

When attempting to secure something, whether it’s a computer, sensitive data, or valuables, there’s always going to be a way to break that security. It might be impossibly hard, like taking centuries to brute-force an encryption algorithm, but it’s weakness is still there. And, like the future might make certain encryption obsolete, modern electronics has made security of the past somewhat obsolete as well. [Startup Chuck] has been using tools the creators of safes from the late 1800s could probably not have imagined.

The tool that [Startup Chuck] has come up with is known as an autodialer in the safe-cracking world, and as its name suggests it automates the process of opening the safe by trying as many combinations as possible. The autodialer attaches to the safe with three magnetic feet and couples to the dial through a chuck attached to a magnetic clutch, which allows the autodialer to disengage as soon as the correct combination is found. It’s driven with a stepper motor which can test out combinations so fast that [Startup Chuck] needed to take 240 fps video and slow it down to make sure that the mechanism was behaving properly.

The autodialer itself can’t actually open the safe, though. The last step of the process is taken care of by a bungie cord, attached to the safe handle to pre-tension it enough so that when the correct combination is finally entered the safe pops open automatically. For anyone looking to duplicate the project, [Startup Chuck] has added the program code to a GitHub page. If you’re looking at a more modern safe, though, there are of course ways to crack their security systems as well.

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