Splashflag: Raising The Flag On A Pool Party

October 5, 2025 by Matt Varian 7 Comments

Some things are more fun when there are more folks involved, and enjoying time in the pool is one of those activities. Knowing this, [Bert Wagner] started thinking of ways to best coordinate pool activities with his kids and their neighborhood friends. Out of this came the Splashflag, an IoT device built from the ground up that provides fun pool parties and a great learning experience along the way.

The USB-powered Splashflag is housed in a 3D-printed case, with a simple 2×16 LCD mounted on the front to display the notification. There’s also a small servo mounted to the rear that raises a 3D-printed flag when the notification comes in—drawing your attention to it a bit more than just text alone would. Hidden on the back is also a reset button: a long press factory-resets the device to connect to a different Wi-Fi network, and a quick press clears the notification to return the device to its resting state.

Inside is an ESP32-S3 that drives the servo and display and connects to the Wi-Fi. The ESP32 is set up with a captive portal, easing the device’s connection to a wireless network. The ESP32, once connected, joins an MQTT broker hosted by [Bert Wagner], allowing easy sending of notifications via the web app he made to quickly and easily send out invitations.

Thanks, [Bert Wagner], for sharing the process of building this fun, unique IoT device—be sure to read all the details on his website or check out the code and design files available over on his GitHub. Check out some of our other IoT projects if this project has you interested in making your own.

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Cold Sensor, Hot Results: Upgrading A DSLR For Astrophotography

October 3, 2025 by Matt Varian 15 Comments

When taking pictures of the night sky, any noise picked up by the sensor can obscure the desired result. One major cause of noise in CMOS sensors is heat—even small amounts can degrade the final image. To combat this, [Francisco C] of Deep SkyLab retrofitted an old Canon T1i DSLR with an external cooler to reduce thermal noise, which introduces random pixel variations that can hide faint stars.

While dedicated astrophotography cameras exist—and [Francisco C] even owns one—he wanted to see if he could improve an old DSLR by actively cooling its image sensor. He began with minor surgery, removing the rear panel and screen to expose the back of the sensor. Using a sub-$20 Peltier cooler (also called a TEC, or Thermoelectric Cooler), he placed its cold side against the sensor, creating a path to draw heat away.

Reassembling the camera required some compromises, such as leaving off the LCD screen due to space constraints. To prevent light leaks, [Francisco C] covered the exposed PCBs and viewfinder with tape. He then tested the setup, taking photos with the TEC disabled and enabled. Without cooling, the sensor started at 67°F but quickly rose to 88°F in sequential shots. With the TEC enabled, the sensor remained steady at 67°F across all shots, yielding a 2.8x improvement in the signal-to-noise ratio. Thanks to [Francisco C] for sharing this project! Check out his project page for more details, and explore our other astrophotography hacks for inspiration.

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A photo of the front-panel with a bunch of lamps and knobs.

The Making Of A Minimalist Analog Drum Machine

October 1, 2025 by John Elliot V 15 Comments

Our hacker [Moritz Klein] shows us how to make a minimalist analog drum machine. If you want the gory details check out the video embedded below and there is a first class write-up available as a 78 page PDF manual too. Indeed it has been a while since we have seen a project which was this well documented.

A typical drum machine will have many buttons and LEDs and is usually implemented with a microcontroller. In this project [Moritz] eschews that complexity and comes up with an analog solution using a few integrated circuits, LEDs, and buttons.

The heart of the build are the integrated circuits which include two TL074 quad op amps, a TL072 dual op amp, a CD4520 binary counter, and eight CD4015 shift registers. Fifteen switches and buttons are used along with seven LEDs. And speaking of LEDs, our hacker [Moritz] seems to have an LED schematic symbol tattooed to his hand, and we don’t know about you, but this screams credibility to us! :)

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RTINGS 10-Year Equivalent TV Longevity Update With Many Casualties

September 24, 2025 by Maya Posch 35 Comments

For the past two-and-half years Canadian consumer testing outfit RTINGS has been running an accelerated aging experiment across a large number of TVs available to a North-American audience. In their most recent update, we not only find out about the latest casualties, but also the impending end of the experiment after 18,000 hours — as the TVs are currently failing left and right as they accelerate up the ascending ramp of the bathtub curve.

Some of these LEDs are dead, others are just wired in series. (Credit: RTINGS.com) — Some of these LEDs are dead, others are just wired in series.

The dumbest failure type has to be the TVs (such as the Sony X90J) where the failure of a single dead backlight LED causes the whole TV to stop working along with series-wired LED backlights where one dead LED takes out a whole strip or zone. Other failures include degrading lightguides much as with our last update coverage last year, which was when edge-lit TVs were keeling over due to overheating issues.

Detailed updates can be found on the constantly updating log for the experiment, such as on the failed quantum dot diffusor plate in a TCL QLED TV, as the quantum dots have degraded to the point of green being completely missing. Although some OLEDs are still among the ‘living’, they’re showing severe degradation – as pictured above – after what would be the equivalent of ten years of typical usage.

Once the experiment wraps up it will be fascinating to see who the survivors are, and what the chances are of still using that shiny new TV ten years from now.

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The Impending CRT Display Revival Will Be Televised

September 23, 2025 by Maya Posch 113 Comments

Until the 2000s vacuum tubes practically ruled the roost. Even if they had surrendered practically fully to semiconductor technology like integrated circuits, there was no escaping them in everything from displays to video cameras. Until CMOS sensor technology became practical, proper video cameras used video camera tubes and well into the 2000s you’d generally scoff at those newfangled LC displays as they couldn’t capture the image quality of a decent CRT TV or monitor.

For a while it seemed that LCDs might indeed be just a flash in the pan, as it saw itself competing not just with old-school CRTs, but also its purported successors in the form of SED and FED in particular, while plasma TVs made home cinema go nuts for a long while with sizes, fast response times and black levels worth their high sale prices.

We all know now that LCDs survived, along with the newcomer in OLED displays, but despite this CRTs do not feel like something we truly left behind. Along with a retro computing revival, there’s an increasing level of interest in old-school CRTs to the point where people are actively prowling for used CRTs and the discontent with LCDs and OLED is clear with people longing for futuristic technologies like MicroLED and QD displays to fix all that’s wrong with today’s displays.

Could the return of CRTs be nigh in some kind of format?

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Test Pattern Generator For SCART And RGB TVs

September 19, 2025 by Tyler August 4 Comments

CRTs don’t last forever, and neither do the electronics that drive them. When you have a screen starting to go wonky, then you need a way to troubleshoot which is at fault. A great tool for that is a pattern generator, but they’re not the easiest to come by these days. [baritonomarchetto] needed a pattern generator to help repair his favourite arcade machine, and decided to make his own DIY Portable RGB CRT Test Pattern Generator.

One of the test patterns available from the device. This TV appears to be in good working order.

While he does cite [Nicholas Murray]’s RP2040 test pattern generator as a starting point (which itself builds on the PicoVGA library once featured here), he couldn’t just build one. That worthy project only outputs VGA and because [baritonomarchetto] is in Europe, he needed a SCART connector. Since he’s working on arcade machines, he needed non-SCART RGB signals, too. The arcade signals need to be at higher voltages (TLL level) than the RGB signal you’d find in SCART and VGA.

The upshot is while he’s using [Nicholas]’s code for the RP2040, he’s rolled his own PCB, including a different resistor ladders to provide the correct voltages depending on if he’s dealing with a home TV or arcade CRT. To make life easier, the whole thing runs off a 9V battery.

If you’re wondering what the point of these test patterns is, check out this 1981-vintage pattern generator for some context from the era. If a digital replica doesn’t float your boat, it is possible to recreate the original analog circuitry that generated these patterns back when the CRT was king.

Haasoscope Pro: Open-Everything 2 GHz USB Oscilloscope

September 19, 2025 by John Elliot V 34 Comments

Our hacker [haas] is at it again with the Haasoscope Pro, a full redesign of the original Haasoscope, which was a successful Crowd Supply campaign back in 2018.

This new Pro version was funded on Crowd Supply in April this year and increases the bandwidth from 60 MHz to 2 GHz, the vertical resolution from 8 to 12 bits, and the sample rate from 125 MS/s to 3.2 GS/s. Selling for $999 it claims to be the first open-everything, affordable, high-bandwidth, real-time sampling USB oscilloscope.

The firmware and software are under active development and a new version was released yesterday.

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