These days, if you are in the market for a capable digital voltmeter, you might as well consider getting one with an oscilloscope built-in. One choice is the Owon HDS160, which [Kerry Wong] covers in the video below. The model is very similar to the HDS120, but the multimeter in the HDS160 has more counts–60,000 vs 20,000 as you might expect from the model number.
The internal chip is an HY3131, which is rated at 50,000 counts which is odd since the meter is 60,000 counts, but presumably the meter uses some capability of the chip, possibly putting it out of spec. The oscilloscope is the same between the two models. Almost everything else works the same, other than the capacitance measuring feature, as the video shows.
The difference in cost between the two units isn’t much, so if you are shopping, the small extra cost is probably worth it. Not that a 20,000 count meter isn’t perfectly fine for most normal uses.
Not all clamp meters are the same, and this video shows just that. In a recent teardown by [Kerry Wong], the new Fnirsi DMC-100 proves that affordable doesn’t mean boring. This 10,000-count clamp meter strays from the classic rotary dial in favour of a fully button-based interface – a choice that’s got sparks flying in the comments. And yes, it even auto-resumes its last function after reboot, like it knows you’re busy frying other fish.
What sets this meter apart isn’t just its snappy interface or surprisingly nice gold-tipped probes. It’s the layered UX – a hackable interface where short- and long-presses unlock hidden menus, memory functions, and even a graphing mode. A proper “hold-my-beer” moment comes when you discover it can split-display voltage and current and calculate real-time power (albeit with a minor asterisk: apparent power only, no power factor). Despite a few quirks, like accidentally triggering the flashlight when squeezing the jaw, it holds up well in accuracy tests. Even at higher currents where budget meters usually wobble.
We’ve all seen those cheap bench power supply units (PSUs) for sale online, promising specifications that would cost at least a hundred dollars or more if it were a name brand model. Just how much of a compromise are these (usually rebranded) PSUs, and should you trust them with your electronics? Recently [Denki Otaku] purchased a cheap unit off Amazon Japan for a closer look, and found it to be rather lacking.
Internals of the cheap bench PSU reviewed by Denki Otaku on YouTube.
Major compromises include the lack of an output power switch, no way to check the set current limit without shorting the output, very slow drop in output voltage while adjusting due to the lack of a discharge circuit, and other usability concerns. That’s when the electrical performance of the PSU got tested.
Right off the bat a major issue in this cheap switching mode PSU is clear, as it has 200 mV peak-to-peak noise on its output, meaning very little output filtering. The maximum power output rating was also far too optimistic, with a large voltage drop observed. Despite this, it generally worked well, and the internals – with a big aluminium plate as heatsink – look pretty clean with an interesting architecture.
The general advice is to get a bench PSU that has features like an output power button and an easy way to set the voltage and current limits. Also do not connect it to anything that cares about noise and ripple unless you know that it produces clean, filtered output voltages.
Continuous glucose meters (CGMs) aren’t just widgets for the wellness crowd. For many, CGMs are real-time feedback machines for the body, offering glucose trendlines that help people rethink how they eat. They allow diabetics to continue their daily life without stabbing their fingertips several times a day, in the most inconvenient places. This video by [Becky Stern] is all about comparing two of the most popular continuous glucose monitors (CGMs): the Abbott Libre 3 and the Dexcom G7.
Both the Libre 3 and the G7 come with spring-loaded applicators and stick to the upper arm. At first glance they seem similar, but the differences run deep. The Libre 3 is the minimalist of both: two plastic discs sandwiching the electronics. The G7, in contrast, features an over-molded shell that suggests a higher production cost, and perhaps, greater robustness. The G7 needs a button push to engage, which users describe as slightly clumsy compared to the Libre’s simpler poke-and-go design. The nuance: G7’s ten-day lifespan means more waste than the fourteen-day Libre, yet the former allows for longer submersion in water, if that’s your passion.
While these devices are primarily intended for people with diabetes, they’ve quietly been adopted by a growing tribe of biohackers and curious minds who are eager to explore their own metabolic quirks. In February, we featured a dissection of the Stelo CGM, cracking open its secrets layer by layer.
We all know periscopes serve for observation where there’s no direct line-of-sight, but did you know they can allow you to peer through history? That’s what [msylvain59] documented when he picked up a British military night vision periscope, snagged from a German surplus shop for just 49 euros. Despite its Cold War vintage and questionable condition, the unit begged for a teardown.
The periscope is a 15-kilo beast: industrial metal, cryptic shutter controls, and twin optics that haven’t seen action since flares were fashionable. One photo amplifier tube flickers to greenish life, the other’s deader than a disco ball in 1993. With no documentation, unclear symbols, and adjustment dials from hell, the teardown feels more like deciphering a British MoD fever dream than a Sunday project. And of course, everything’s imperial.
Despite corrosion, mysterious bulbs, and non-functional shutters, [msylvian59] uncovers a fascinating mix of precision engineering and Cold War paranoia. There’s a thrill in tracing light paths through mil-spec lenses (the number of graticules seen that are etched on the optics) and wondering what secrets they once guarded. This relic might not see well anymore, but it sure makes us look deeper. Let us know your thoughts in the comments or share your unusual wartime relics below.
Recently [Dillan Stock] bought a $17 ‘mushroom’ lamp from his local Kmart that listed ‘USB-C rechargeable’ as one of its features. Unfortunately while this is technically true, there’s a pretty major asterisk. This Inaya-branded lamp comes with a USB-C cable with a rather prominent label attached to it that tells you that this lamp requires that specific cable. After trying with a regular USB-C cable, [Dillan] indeed confirmed that the lamp does not charge from a standard USB-C cable. So he did what any reasonable person would do: he bought a second unit and set about to hacking it.
The “USB C” cable that comes with the Inaya Portable Rechargeable Lamp. (Credit: The Stock Pot, YouTube)
[Dillan] also dug more into what’s so unusual about this cable and the connector inside the lamp. As it turns out, while GND & VCC are connected as normal, the two data lines (D+, D-) are also connected to VCC. Presumably on the lamp side this is the expected configuration, while using a regular USB-C cable causes issues. Vice versa, this cable’s configuration may actually be harmful to compliant USB-C devices, though [Dillan] did not try this.
With the second unit in hand, he started hacking in earnest. The changes include a regular USB-C port for charging, an ESP32 board with integrated battery charger for the 18650 Li-ion cell of the lamp, and an N-channel MOSFET to switch the power to the lamp’s LED. He’s made the full plans and schematics available on his website.
With all of the raw power from the ESP32 available, the two lamps got integrated into the Home Assistant network which enables features such as turning the lamps on when the alarm goes off in the morning. All of this took about $7 in parts and a few hours of work.
Although we commend [Dillan] on hacking his device instead of just returning it to the store, it’s worrying that apparently there’s now a flood of ‘USB C-powered’ devices out there that come with non-compliant cables. It brings back fond memories of hunting down proprietary charging cables, which was the issue that USB power was supposed to fix.
Getting a look at the internals of a garden variety “wall wart” isn’t the sort of thing that’s likely to excite the average Hackaday reader. You’ve probably cracked one open yourself, and even if you haven’t, you’ve likely got a pretty good idea of what’s inside that sealed up brick of plastic. But sometimes a teardown can be just as much about the journey as it is the end result.
Truth be told, we’re not 100% sure if this teardown from [Brian Dipert] over at EDN was meant as an April Fool’s joke or not. Certainly it was posted on the right day, but the style is close enough to some of his previous work that it’s hard to say. In any event, he’s created a visual feast — never in history has an AC/DC adapter been photographed so completely and tastefully.
An Ode to the Diode
[Brian] even goes so far as to include images of the 2.5 lb sledgehammer and paint scraper that he uses to brutally break open the ultrasonic-welded enclosure. The dichotomy between the thoughtful imagery and the savage way [Brian] breaks the device open only adds to the surreal nature of the piece. Truly, the whole thing seems like it should be part of some avant garde installation in SoHo.
After he’s presented more than 20 images of the exterior of the broken wall wart, [Brian] finally gets to looking at the internals. There’s really not much to look at, there’s a few circuit diagrams and an explanation of the theory behind these unregulated power supplies, and then the write-up comes to a close as abruptly as it started.
So does it raise the simple teardown to an art form? We’re not sure, but we know that we’ll never look at a power adapter in quite the same way again.
