New Display For Old Multimeter

April 14, 2026 by Bryan Cockfield 13 Comments

As a company, Fluke has been making electronic test equipment longer than the bipolar junction transistor has been around for. In that time they’ve developed a fairly stellar reputation for quality and consistency, but like any company they don’t support their products indefinitely. [ogdento] owns a Fluke meter that isn’t nearly as old as the BJT but still has an age well outside of the support window, and since the main problem was the broken LCD display they set about building a replacement for this retro multimeter.

Initially, [ogdento] had plans to retrofit this classic multimeter with a modern OLED, but could not find enough space for the display or a way to drive it easily. The next attempt to get something working was to build a custom one-off LCD using a drill press as an end mill, which didn’t work either. But after seeing a Charlieplexed display from [bobricius] as well as this video from EEVblog about designing custom LCDs, [ogdento] was able to not only design a custom PCB and LCD display to match the original meter, but was able to get a manufacturer in China to build them.

The new displays have a few improvements over the old; mostly they are more stylistically inspired by later Fluke models and have a few modern improvements to the LCD itself. There were are few issues during prototyping but nothing that was too hard to sort out, such as ordering the wrong size elastomeric strips initially. For anyone who needs to replace a custom LCD and can’t find replacement parts anymore, this project would be a great starting point for figuring out the process from the ground up.

A Computer That Fits Inside A Camera Lens

February 16, 2026 by Bryan Cockfield 30 Comments

For a long while, digital single-lens reflex (DSLR) cameras were the king of the castle for professional and amateur photography. They brought large sensors, interchangeable lenses, and professional-level viewfinders to the digital world at approachable prices, and then cemented their lead when they started being used to create video as well. They’re experiencing a bit of a decline now, though, as mirrorless cameras start to dominate, and with that comes some unique opportunities. To attach a lens meant for a DSLR to a mirrorless camera, an adapter housing must be used, and [Ancient] found a way to squeeze a computer and a programmable aperture into this tiny space.

The programmable aperture is based on an LCD screen from an old cell phone. LCD screens are generally transparent until their pixels are switched, and in most uses as displays a backer is put in place so someone can make out what is on the screen. [Ancient] is removing this backer, though, allowing the LCD to be completely transparent when switched off. The screen is placed inside this lens adapter housing in the middle of a PCB where a small computer is also placed. The computer controls the LCD via a set of buttons on the outside of the housing, allowing the photographer to use this screen as a programmable aperture.

The LCD-as-aperture has a number of interesting uses that would be impossible with a standard iris aperture. Not only can it function as a standard iris aperture, but it can do things like cycle through different areas of the image in sequence, open up arbitrary parts or close off others, and a number of other unique options. It’s worth checking out the video below, as [Ancient] demonstrates many of these effects towards the end. We’ve seen some of these effects before, although those were in lenses that were mechanically controlled instead.

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Real LED TVs Are Finally Becoming A Thing

February 16, 2026 by Zoe Skyforest 58 Comments

Once upon a time, the cathode ray tube was pretty much the only type of display you’d find in a consumer television. As the analog broadcast world shifted to digital, we saw the rise of plasma displays and LCDs, which offered greater resolution and much slimmer packaging. Then there was the so-called LED TV, confusingly named—for it was merely an LCD display with an LED backlight. The LEDs were merely lamps, with the liquid crystal doing all the work of displaying an image.

Today, however, we are seeing the rise of true LED displays. Sadly, decades of confusing marketing messages have polluted the terminology, making it a confusing space for the modern television enthusiast. Today, we’ll explore how these displays work and disambiguate what they’re being called in the marketplace.

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5K IMac Turned Into 5K Display

February 4, 2026 by Bryan Cockfield 12 Comments

While Apple weren’t the first to invent high-DPI displays or to put them into consumer electronics, they did popularize them fairly effectively with the Retina displays in the early 2010s and made a huge number of them in the following years. The computers they’re attached to are getting up there in age, though, and although these displays are still functional it isn’t quite as straightforward to use them outside of their Apple-approved use. [David] demonstrates one way of getting this done by turning a 5k iMac into an external monitor.

The first attempt at getting a usable monitor from the old iMac was something called a Luna Display, but this didn’t have a satisfying latency. Instead, [David] turned to replacing the LCD driver board with a model called the R1811. This one had a number of problems including uneven backlighting, so he tried a second, less expensive board called the T18. This one only has 8-bit color instead of the 10-bit supported by the R1811 but [David] couldn’t personally tell the difference, and since it solved the other issues with the R1811 he went with this one. After mounting the new driver board and routing all of the wires, he also replaced the webcam with an external Logitech model and upgraded the speakers as well.

Even when counting the costs for both driver boards, the bill for this conversion comes in well under the cost of a new monitor of comparable quality from Apple, a company less concerned about innovation these days than overcharging their (admittedly willing) customers. For just a bit of effort, though, these older iMacs and other similar Apple machines with 5k displays can be repurposed to something relatively modern and still usable. Others have done similar projects and funded the upgrades by selling off the old parts.

A 1990s VNA Gets An LCD

January 10, 2026 by Jenny List 8 Comments

A Vector Network Analyser, or VNA, is the ultimate multi-tool of RF test equipment. They can now be had in not very capable form for almost pocket money prices, but the professional-grade ones cost eye-watering sums. Enough to make an older VNA for a few hundred on eBay a steal, and [W3AXL] has just such a device in an HP 8714C. It’s the height of 1990s tech with a floppy drive and a green-screen CRT, but he’s homing right in on the VGA monitor port on the back. Time for a colour LCD upgrade!

There are two videos below the break, posted a year apart, because as we’re sure many of you will know, events have a habit of getting in the way of projects. In the first, we see the removal of the CRT module and safe extraction of its electronics, followed by the crafting of a display bezel for the LCD. Meanwhile, the second video deals with the VNA itself, extracting the VGA signal and routing it forward to the new module. Continue reading “A 1990s VNA Gets An LCD” →

Shelf Life Extended: Hacking E-Waste Tags Into Conference Badges

December 3, 2025 by Matt Varian 10 Comments

Ever wonder what happens to those digital price tags you see in stores once they run out of juice? In what is a prime example of e-waste, many of those digital price tags are made with non-replaceable batteries, so once their life is over they are discarded. Seeing an opportunity to breathe new life into these displays, [Tylercrumpton] went about converting them to be the official badge of the Phreaknic 26 conference.

Looking for a solution for a cheap display for the upcoming conference badge, [Tylercrumpton] recalled seeing the work [Aaron Christophel] did with reusing electronic shelf labels. Looking on eBay, he picked up a lot of 100 ZBD 55c-RB labels for just $0.70 a piece. When they arrived, he got to work liberating the displays from their plastic cases. The long-dead batteries in the devices ended up being easily removed, leaving behind just the display and the PCB that drives it.

Another hacker assisting with the badge project, [Mog], noticed that the spacing of the programming pads on the PCB was very close to the spacing of a DB9/DE9 cable. This gave way to a very clever hack for programming the badges: putting pogo pins into a female connector. The other end of the cable was connected to a TI CC Debugger which was used to program the firmware on the displays. But along the way, even this part of the project got an upgrade with moving to an ESP32 for flashing firmware, allowing for firmware updates without a host computer.

The next challenge was how to handle customizing 200 unique badges for the conference. For this, each badge had a unique QR code embedded in the back of the 3D printed case that pointed to an online customization tool. The tool allowed the user to change which of the images was used for the background, as well as input the name they wanted to be displayed on the badge. Once finished, the server would provide a patched firmware image suitable for flashing the badge. The original intent was to have stations where attendees could plug in their badge and it would update itself; however, due to some 11th hour hiccups, that didn’t pan out for this conference. Instead, [Tylercrumpton] ran the update script on his machine, and it gave him a great opportunity to interact with conference attendees as they stopped by to update their badges.

For the Phreaknic 27 badge, the plan is to once again use electronic shelf labels, but this time to utilize some of the advanced features of the tags such as the EEPROM and wireless communications. We’re eager to see what the team comes up with.

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How To Design Custom LCDs For Your Own Projects

October 4, 2025 by Zoe Skyforest 10 Comments

These days, you can buy full graphical LCD or OLED displays for just a few dollars. However, if you’re so inclined, you can actually get your own segmented LCDs made to suit your own projects. [Icoso Labs] explains how it’s done, with plenty of handy tips along the way.

There are three primary things you need to do to design a segmented LCD. First, you need to design it visually, laying out all the individual elements you want on the display. Then you need to determine how you want to split them up into segments. Some elements you’ll just want to be a single monolithic on-or-off shape, while other areas you might want to create things like seven-segment numerals for displaying numbers and so on. With that done, you also need to specify various engineering details—such as whether you want a transmissive, reflective, or transflective display, and thicknesses, colors, and other important things. Armed with all that, you can take your design to a manufacturer and get them to make a bunch for you. Often, there’s a moderately high tooling cost to start a run, but you can then turn out more examples of your design for just a few bucks apiece.

It’s a neat guide to designing something few of us have ever considered sourcing for ourselves. We’ve featured other insights into the world of segmented LCDs before, too. Video after the break.

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