Ask Hackaday: How Do You Feel About Electronic Shelf Labels?

June 4, 2026 by Tom Nardi 145 Comments

Unless you’ve spent the last few years locked indoors and had all of your goods delivered to you — a not entirely implausible situation, given our audience — you’ve likely noticed the growing popularity of electronic shelf labels (ESLs). They’ve been a common sight in grocery stores like Aldi for some time, and major retailers such as Walmart and Home Depot have been expanding their use of the technology.

On the surface, it makes perfect sense. With electronic ink displays, you can create a price tag that looks enough like a paper label that the customer’s experience isn’t really any different, but the retailer doesn’t have to send somebody out to update the prices. Sure, the upfront cost is higher than a roll of sticky paper, but theoretically, the ESLs should pay for themselves thanks to the reduced labor costs.

It’s the sort of high-tech solution to a common problem that one of us would have come up with. If this were a decade ago, we wouldn’t have been surprised to see something like this get entered into the Hackaday Prize. It might have even won.

Now that the technology is becoming commonplace, there’s even more reason for hardware hackers to be interested in it. Since most of these tags will show whatever image you beam over to them via radio or infrared, we’ve seen a number of projects that repurpose second-hand tags as convenient data displays.

Rather than showing the price of milk, they can show the current price of Bitcoin. Or maybe you’d like to stick them up all over the house to display the weather forecast and your family calendar. They’ve been repurposed as badges at hacker cons, and at least one industrious hacker has used a discarded ESL to show an alert whenever a new episode of the Hackaday Podcast drops.

But not everyone is happy about ESLs. Recently, the United Food and Commercial Workers (UFCW) International Union released the results of a poll showing that most American consumers are opposed to ESLs, citing concerns that the technology would ultimately lead to higher prices.

Continue reading “Ask Hackaday: How Do You Feel About Electronic Shelf Labels?” →

Make Your Ceiling Disappear With ADS-B And Short-Throw Projector

June 4, 2026 by Tyler August 13 Comments

If you’re into airplanes, you’ve probably had the experience of hearing an unusual aircraft and rushing outside to try and catch a glimpse of it, all while fumbling with a smartphone to open a flight-tracking app. If your home was equipped with [cpaczek]’s Skylight project, which combines ADS-B data with a short throw projector, that little dance would have been totally unnecessary.

ADS-B or the “Automatic Dependent Surveillance-Broadcast”, is the standard by which aircraft broadcast their position and other flight information from onboard transponders. In most of the world, every commercial aircraft has an ADS-B transmitter, and they’re slowly creeping into general aviation as well. The signals aren’t hard to pick up with software-defined radio — like perhaps this RP2040 based unit we featured — or the RTL-SDR v4 this project calls for.

Using data from ADS-B, the Skylight software runs on Raspberry Pi 5 and renders icons of the aircraft exactly where they would appear above you, if that pesky ceiling wasn’t in the way. You get the flight’s code, destination and flightplan with a nice icon representing what type of airplane it is. Thanks to specifying a Pi 5, the projection is a smooth 60 FPS at 1080p. Airplanes aren’t the only things plotted, though — this is also a planetarium, giving you a full view of the stars and any satellites passing overhead. That’s obviously via an API, not SDR, and if you like you can configure it to track aircraft that way to — allowing you to set your Skylight for anywhere in the world, if you aren’t near an interesting airport.

ADS-B isn’t just for pilots and plane nerds — if you’re flying drones, you probably should keep an eye on it, too. In that case, though, you probably won’t be looking at your ceiling.

Thanks to [Thinkerer] for the tip!

Fixing A Nintendo Game Boy Clone That Runs Too Fast

June 4, 2026 by Maya Posch 10 Comments

There’s no shortage of cloned Nintendo hardware out there, and most of it is pretty poor. A few are actually pretty interesting though, such as the GB Boy by Gangfeng, which takes real cartridges and thus in many ways should provide the original Game Boy Pocket experience with modern hardware. But as you might imagine, even the best of the clones comes with various technical issues at no additional charge — with this particular unit having a habit of running the game too fast. It’s an issue that [Sharopolis] addresses in a recent video with a partial fix.

As can be seen in the demonstration, it runs games just too fast to make it very usable or fun, hence why it sat in a drawer for a few years after purchasing off AliExpress. This raises the question of what’s wrong with these units, as others report similar issues with this and other ‘GB Boy’ variants.

Fortunately the unit is easy to open, revealing the PCB with a couple of chips on it, one marked KF2001 being the brains of the operation alongside two memory chips. The crystal resonator marked X1 for the main IC is rated for 5 MHz, whereas a quick look inside the Game Boy Pocket shows that its crystal resonator runs at 4.1943 MHz, which is a bit of a difference.

Because of how buying components and pricing works, [Sharopolis] ended up with a reel of 100 of replacement resonators with the right parameters for a drop-in replacement. After swapping the resonator, the GB Boy now does indeed run games at the right speed, but a new issue has now cropped up in the form of flicker on the display.

In the comments it’s suggested that replacing the cheap capacitors on the GB Boy’s board can help here, but it highlights just how these clone systems keep managing to snatch defeat from the jaws of victory by pairing what looks to be a pretty good IC with either the wrong or sub-par components.

Continue reading “Fixing A Nintendo Game Boy Clone That Runs Too Fast” →

Web-Based Control For A CB Radio

June 3, 2026 by Jenny List 20 Comments

There was a time when a CB radio was a simple affair: a small box with a channel selector, volume, and squelch controls. No longer it seems, because they can now be multi-mode devices that equal the capabilities of amateur radio rigs if not surpass them. [ThatCrazyDcGuy] has one, an Albrecht AE-5900, which has the interesting feature that it can be entirely controlled from its microphone. This led to a web-based interface for the rig, through clever emulation of the microphone.

The communication between rig and microphone is a serial line, for which an FT232 USB-to-serial interface is pressed into service. A USB sound card handles the audio along with some little transformers for isolation, and a USB hub joins everything together. The whole is mounted on perfboard in a small enclosure, and plugged into a Raspberry Pi which acts as a server. This is running a Python script that expose a web front end to control the rig. We like the way this has been done, with minimal intrusion into the radio itself.

Far less so than this CB to 6 meter conversion we featured a while back.

Distilling Stale Gasoline To Make It Usable Again

June 3, 2026 by Maya Posch 38 Comments

Pouring the resulting distillate for testing. (Credit: Lowered Expectations, YouTube)

The propensity of gasoline to ‘go stale’ through the process of oxidation is the reason why gasoline that has been stored for a long period of time is considered to be unusable, as it will no longer combust property. Since this process creates the sludge that you find in the bottom of an old gasoline canister, it follows that you may be able to distill out the still good gasoline. With this reasoning, [Joel] over at the [Lowered Expectations] channel set to work to try out this theory.

As part of his job of maintaining things like pressure washers, he got access to many grades of stale gasoline to experiment with. After a short demonstration of how poorly these grades of stale gasoline burn it’s on to the main distillation event. To the stale gasoline aluminium oxide is added as both a catalyst and to create nucleation sites that will prevent ‘bumping’ where you suddenly get a surge out of the heated flask.

Of course, that this is incredibly dangerous should be obvious, and the lack of PPE on the side of [Joel] is somewhat worrying. On the positive side, he does take it easy with ramping up the temperature on the gasoline to try and find the sweet spot where production seems sufficient. This turned out to start at 70°C in the flask when the condenser began to receive its first load of presumably clean-ish gasoline.

The goal here is of course to approximate the function of the fractionating column (‘distillation tower’) at refineries at smaller scale, which [Joel] appears to be doing correctly with what looks to be a Vigreaux column. Since the base product is gasoline with oxidized contaminants this process is of course quite different, so he goes through the different temperature ranges to see what kind of distillate he gets, up to nearly 200°C before calling it.

Ultimately 880 mL of the initial 1 L was collected, with the various distillates combined for testing. Unfortunately none of the testing is actually covered in the video, but it is mentioned at the end that a second batch of the distillate was used to power his car, so presumably it works.

Suffice it to say that ‘works’ doesn’t mean that it is safe, of course. Heating such stale gasoline produces many highly flammable and combustible substances, along with many that are just downright bad for your health to be exposed to. The plethora of very short-term to all the way to very long-term health effects this may cause should be obvious.

Continue reading “Distilling Stale Gasoline To Make It Usable Again” →

DIY Ceramic Circuit Boards Surely Count As Solarpunk

June 3, 2026 by Tyler August 12 Comments

Solarpunk is all about combining that DIY hacker ethos with sustainability and renewable resources. Our usual PCB manufacturing methods, with their bevy of chemical baths and petrochemical resins aren’t exactly the most sustainable. Digging up some clay and firing it into a circuit board? Very sustainable! And apparently doable, as demonstrated by [Emily Velasco] on Mastadon.

Of course anybody could take a ceramic wafer and call it a circuit board, but that’s only part of what [Emily] did. The ceramic wafer is apparently native clay, which is very cool. Even cooler is that she’s baked the traces into the pottery. While you could conceivably use some sort of conductive glaze for this, what [Emily] did was stamp her desired circuit into the unfired ceramic using a 3D-printed stamp, and then fill the depression with copper powder after the first firing. After that, a second firing is done in a reducing atmosphere to melt/sinter the copper together–it’s not totally clear which is happening here–without burning up.

The results speak for themselves; on the finished demo board, a pair of LEDs blink happily away, driven by the astable oscillator circuit baked right into the clay– and of course the components soldered to it. You’ll have to click through to see it, though.

Given those not-so-sustainable petrochemicals behind our favourite PCBs may be in short supply, this is a timely hack. If it seems familiar, that’s because we featured virtually the same technique last year, but using more-expensive silver powder instead of copper, and a campfire instead of a kiln.

Thanks to [smellsofbikes] for the tip!

Texas Instruments Changes The NE5532 And Others Into Incompatible Versions

June 3, 2026 by Maya Posch 44 Comments

First introduced in 1979 by Signetics, the NE5532 was a pretty spiffy dual op-amp for the time with low noise and low distortion. Over the years it has become a standard part that showed up in countless audio products, and has become a so-called jellybean generic component with Texas Instruments (TI) being one of countless manufacturers.

It being such a standard, multi-sourced part makes it thus even more puzzling that TI has now decided to completely overhaul this IC in a way that makes it incompatible with even the original Signetics NE5532. These changes are covered in detail by [Dave] of EEVblog as his mind is pretty much blown at such an incomprehensible change.

The changes entail an entirely different manufacturing process and a big change in specifications, while making no change to the part number. In revision K of the TI datasheet these changes are first seen, with some specifications changed for the better, like a higher unity gain bandwidth by 2 MHz, but a much slower slew rate.

Although the 5532 op-amps are multi-sourced, there are good reasons to just stick with manufacturers like TI, as that means receiving a product change notification (PCN) when anything changes. In the PCN related to this op-amp a change to process node is noted, along with other changes, but no reasoning.

Among the other big changes are a reduction in the supply voltage from 22 V to 18 V, and a halving of the ESD protection from 2 kV to 1 kV. Although it might be slightly more efficient on the new process node this way, it clearly comes with a lot of trade-offs that make it an overall worse op-amp, while also being incompatible with the same op-amp from other manufacturers.

In the video [Dave] goes through the datasheets of this jellybean part of other manufacturers, showing that they still have the original 1980s specifications. Only one exception here was the NE5532DR from Shenzhen HuaXuanYang Electronics, whose supply rail voltage is also 18 V for some reason, along with a similar internal transistor configuration that reduces the ESD resistance.

In addition to the NE5532 op-amp, it seems that TI also took an axe to the OPA134 op-amp, by removing its offset trim feature and listing the pins as ‘NC’, with a warning to not connect these pins and also worsening other specifications. This makes these similar jellybean parts incompatible, with no change to the part number. Worse is that it continues with the LMH6518, whose changes [Dave] argues might even kill oscilloscopes as they are commonly found in those.

Meanwhile the LM317M also got an overhaul, but here TI opted to give it a new part name, calling it the LM317MQ with at first glance no major degradations in the specifications, but instead some actual improvements. This makes it even more puzzling why TI didn’t give the other ICs a new part number to differentiate them from the jellybean part.

Until there’s some clarification from the side of TI, it might be a good idea to source these parts from a manufacturer that is not TI, especially when replacing these ICs in older devices.

Continue reading “Texas Instruments Changes The NE5532 And Others Into Incompatible Versions” →