Garden Hose Gets Laminar Flow

June 8, 2025 by Al Williams 14 Comments

We aren’t sure if [Joshua Bellamy] is serious that he wants a laminar flow to water his plants, but there are many places where having a smooth and predictable flow of water is useful or even essential. With his 3D printed adapter, you can produce laminar flow from any garden hose.

If you haven’t heard the term before, laminar flow is to water what a laser is to light. The water moves in parallel tracks with minimal mixing and turbulence. Ensuring laminar flow is often critical to precise flow metering, for example.

This isn’t [Joshua]’s first attempt. He has made a nozzle like this before, but it required a lot of assembly (“more fiddly bits than a Swedish flat-pack sofa” according to the post). Depending on the version, you’ll need various bits of extra hardware in addition to the 3D printed parts. Some versions have drop-in nuts and even an LED. Fiberglass insulation at the inlet diffuses turbulence, and some manual work on the output provided better results. When everything is working, the output of the hose should look like a glass rod, as you can see in the video below.

Air can also have laminar or non-laminar flow. Laminar air flow in a laser cutter’s air assist can make a big difference. If you don’t fancy 3D printing, you could save some drinking straws from your last few hundred trips to the local fast food emporium.

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Wireless Power Makes For Cable-Free Desk

June 8, 2025 by Tyler August 31 Comments

Some people hate cables with a passion; others are agnostic and prefer cabled peripherals to having to stop and charge their mouse. [Matt] from DIYPerks has the best of both worlds with this wireless-powered, no-cable desk setup.

The secret is embedded within the plywood desk: an evaluation kit from Etherdyne Technologies, Inc consisting of a 100 W RF power supply and its associated power antenna looping around the desktop edge. The mechanism is similar to the inductive charging often seen on phones nowadays, but at higher frequency and larger scale, enabling power to be transmitted several feet (at least a meter) above the desktop.

The range is impressive (this isn’t the maximum), but the efficiency is not advertised.

The kit from ETI contained several PCB-coil receivers, which [Matt] built into a number of devices, including a lamp, heated cup, microphone, speakers, his mouse, keyboard, and even a custom base to run his monitor, which really shows the power these things can pull.

The microphone is a non-Bluetooth RF unit lovingly modified to studio quality, at least as far as we can tell on laptop speakers through YouTube’s compression. The speakers use a pair of Bluetooth modules to negotiate stereo sound while staying in sync. And before you ask “what about signal for the monitor?”– we have to inform you that was taken care of too, via a wireless HDMI dongle. Check it out in the video below.

Of course the elephant in the room here is power usage — there’s a 10 W base draw, and probably a big hit to efficiency vs cabled-everything– but we figure he gets partway to a pass on that by using a Frameworks mainboard instead desktop hardware. Indeed, a full analysis might show that the transmission efficiency of this system is no worse than the power to charge/discharge inefficiencies in a more conventional battery powered wireless setup.

While no wires is pretty clean, we’re not sure this beats the totally-hidden-in-the-desk PC [Matt] built last year in terms of minimalist aesthetic. That Frameworks mainboard also likely lacks the power of his triple-screen luggable, but this was still an entertaining build.

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Hackaday Links: June 8, 2025

June 8, 2025 by Dan Maloney 20 Comments

When purchasing high-end gear, it’s not uncommon for manufacturers to include a little swag in the box. It makes the customer feel a bit better about the amount of money that just left their wallet, and it’s a great way for the manufacturer to build some brand loyalty and perhaps even get their logo out into the public. What’s not expected, though, is for the swag to be the only thing in the box. That’s what a Redditor reported after a recent purchase of an Nvidia GeForce RTX 5090, a GPU that lists for $1,999 but is so in-demand that it’s unobtainium at anything south of $2,600. When the factory-sealed box was opened, the Redditor found it stuffed with two cheap backpacks instead of the card. To add insult to injury, the bags didn’t even sport an Nvidia logo.

The purchase was made at a Micro Center in Santa Clara, California, and an investigation by the store revealed 31 other cards had been similarly tampered with, although no word on what they contained in lieu of the intended hardware. The fact that the boxes were apparently sealed at the factory with authentic anti-tamper tape seems to suggest the substitutions happened very high in the supply chain, possibly even at the end of the assembly line. It’s a little hard to imagine how a factory worker was able to smuggle 32 high-end graphics cards out of the building, so maybe the crime occurred lower down in the supply chain by someone with access to factory seals. Either way, the thief or thieves ended up with almost $100,000 worth of hardware, and with that kind of incentive, this kind of thing will likely happen again. Keep your wits about you when you make a purchase like this.

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Bringing A Father Ted Joke To Life

June 8, 2025 by Matt Varian 8 Comments

Inspired by a gag from a mid-90s sitcom Father Ted, [Stephen] decided to create his own talking tape dispenser.

This project is a actually a follow-up to the first version of the dispenser he built back in 2022, and [Stephen] has documented the process thoroughly for anyone wanting to build their own. In the first version, he modified a tape dispenser to house a Raspberry Pi, enabling voice functionality. In the new version, he replaced the Raspberry Pi with a cheaper ESP8266 and designed an entirely 3D printed dispenser that looks closer to the screen-used version.

A clever change was replacing the rotary encoder with a custom encoder embedded in the printed parts. Using a photodiode and an LED, it measures the tape pulled from the spool. As you pull the tape, the encoder calculates the length and announces it through the speaker, just like in the show.

If you’re into prop recreations like this, be sure to check out the winners of our 2022 Sci-Fi Contest.

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The Saleae logic analyzer software is shown. One PWM channel is active, with values of 0x0001 displayed above the individual waveforms. On the right panel of the app, a trigger mode configuration panel is open for the simple parallel analyzer.

Simple Triggering For Saleae Logic Analyzers

June 8, 2025 by Aaron Beckendorf 4 Comments

Saleae logic analyzers seem to have it all: good sampling rates, convenient protocol decoding, and plenty of channels – but not a good way to set rising or falling-edge triggering. [James] found this rather inconvenient when debugging embedded devices, and shared a workaround that replicates these simple triggering modes.

Crucially, the logic analyzer’s software has a repeated triggering mode that fires when the protocol decoder detects a preset value. [James] used a clever trick to turn this into a rising-edge trigger: he set up a simple parallel analyzer, and set the signal in question as both the sampled channel and the clock signal. Since he wanted to detect the rising edge, he set the clock mode accordingly. Next, he loaded the simple parallel decoder’s trigger configuration and set it to detect a value of one, the value of a high signal. When he ran the simple parallel trigger, every rising edge of the input signal would trigger the clock to check for a high value on the line, in turn triggering the analyzer.

It’s also possible to set up a falling-edge trigger by selecting the falling-edge clock mode and setting the trigger mode to detect a value of zero. Setting up more complex triggers involving multiple channels is as simple as calculating the hexadecimal value of the desired state and setting the parallel decoder to trigger on that value. For example, if you want to trigger when one input is low and another is high, you can set the decoder to trigger on a value or one or two, depending on which order the inputs come in.

If all this makes you interested in Saleae logic analyzers, we’ve seen them used for everything from floppy disk preservation to signal generation. We’ve even reviewed their earliest model back in 2009.

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Piano Doorbell Adds Music To Your Home

June 8, 2025 by Lewin Day 16 Comments

Regular ding-dong doorbells are fun and all, but it can be nice to put something a little more special by your front door. To that end, [Arpan Mondal] built this neat little piano doorbell to make visiting his home just a touch more fun.

The heart of the build is an ESP32 microcontroller. It’s responsible for reading the state of five 3D printed piano keys: three white, two black. It’s nowhere near a full octave, but for a doorbell, it’s enough. When a key is pressed, the ESP32 plays a short audio sample embedded within the program code itself. This is done with the help of a PAM8403 audio amplifier module, which jacks up the output to drive the doorbell speaker loud enough to be heard throughout the home. It’s not exactly studio quality audio, but for a doorbell, it sounds pretty solid.

If you’re looking for a fun and easy build to make your home just a little bit more whimsical, it’s hard to beat something like this. Your musical friends will love it—they might even develop an intro riff of their very own. We’ve featured some other fun doorbell builds before, too—the best of which are the Halloween projects.
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A Close Look At The Mitxela Precision Clock Mk IV

June 8, 2025 by John Elliot V 12 Comments

Over on his secondary YouTube channel, [Jeff Geerling] recently demoed the new Mitxela Precision Clock Mk IV.

This clock uses GPS to get the current time, but also your location so it can figure out what time zone you’re in and which daylight savings time might apply. On the back a blinking diode announces the arrival of each second. A temperature-compensated crystal oscillator (TCXO) is employed for accurate time-keeping.

The clock can be folded in half, thereby doubling as a clapperboard for movie makers. The dimming system is analog, not pulse width modulation (PWM), which means no visible flashing artifacts when recording. It is highly configurable and has USB connectivity. And it has not one but two ARM microcontrollers, an ARM STM32L476, and an ARM STM32L010. If you’re interested, you can pick one up for yourself from [Mitxela]’s shop.

Toward the end of his video [Jeff] does some navel gazing, thinking about what might be required if future versions of the clock wanted to get down into precision at the nanosecond level. Do you arrange it so the light arrives at the viewer’s eyeball at the right time? Or do you update it on the clock at the right time and let the viewer know about it after a minuscule delay? Philosophical preponderances for another day!

We should add that we’ve seen plenty of cool stuff from [Mitxela] before, including the Euroknob and these soldering tweezers.

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