Having the information shown on the display of a digital multimeter also recorded off-screen can be incredibly useful, but unless the device exposes something like SCPI on a network interface, you will have to get creative. In the case of the budget ANENG AN870 digital multimeter (DMM), [Bits und Bolts] really wanted to show its display clearly as an overlay in OBS instead of just the camera view, but with said DMM not offering an easy way he had to resort to just copying the data sent to its multiplexed LCD.
The GitHub project page contains the background information, as well as the instructions if you too have this DMM. It might of course also be useful as the jumping off point for your own DMM modification. In total the project requires three modules: an RP2040 Zero and HC-12 433 MHz transceiver on the DMM side, and another HC-12 plus ESP32-C3 module on the receiving side. A boost module is also added to generate 3.3 V out of the 2.4 V – 3 V provided by the meter’s two AA cells.
To be able to read the LCD signal lines, a custom PCB was created that is installed inside the DMM. With the LCD’s segments mapped, this meant being able to send a perfect copy of the display’s state to the ESP32-C3 and from there making it available via WiFi.
Counterpoint says rising AI memory demand helped drive smartphone shipments to their weakest second quarter since 2013 as DRAM and NAND costs climbed.
The post AI’s Memory Boom Is Reshaping the Smartphone Market appeared first on TechRepublic.
Counterpoint says rising AI memory demand helped drive smartphone shipments to their weakest second quarter since 2013 as DRAM and NAND costs climbed.
The post AI’s Memory Boom Is Reshaping the Smartphone Market appeared first on TechRepublic.
Integrated electronic modules like counters and displays are convenient and space-saving, which may also make them easy to take for granted. [Nagy Krisztián] demonstrates this by making three very different digital counter designs, each breadboarded with a 7-segment LED display. Push a button, and the displayed number increments by one for each press. It was a personal project that ended up educational in more ways than one.
The first version uses discrete components only, and even though it handles the counting with CD4026B decade counter ICs instead of building counters from scratch with NAND gates, it’s still by far the largest of the three. The second version simplifies driving the display with an AT28C64B EEPROM acting as a sort of hardware lookup table translating binary counts into 7-segment digit display patterns. The third uses an ATtiny24A microcontroller, and unsurprisingly has the smallest footprint.
All of this highlights two things. One is that implementing even a simple counter and 7-segment LED readout is a nontrivial affair when one gets right down to it, even when taking advantage of purpose-built ICs. The second is that the complexity that is on full display in the first version doesn’t simply disappear as the footprint and component count goes down. Rather, it moves into software and other infrastructure, like the need for compilers and chip programmers.
The whole thing is both educational and a reminder of how good the average hardware hacker has it today. There are so many effective electronic assemblies, available to just about anyone at low cost, that it can be very easy to take it all for granted and forget just how much breadboard space and wires were needed for even simple-seeming things.
[Nagy] is certainly no stranger to dealing with a lot of wires, as we’ve seen when he fooled a 286 processor into thinking it was plugged into a functioning vintage motherboard.
How old is the seven-segment display? Surely it is a product of the 1970s. After all, calculators started showing up, and the height of junior high humor was plugging 7734 into your calculator and showing it to someone upside down. Of course, for it to go mainstream, maybe they really originated in the 1960s, but no earlier than that, right? Actually, no. Sure, the LED seven-segment display had to wait for LEDs. But the actual idea is much older than that.
The concept of building numbers from a small set of reusable segments predates LED displays by decades. In fact, the basic idea appears in patents from the early 1900s and may have roots in even older mechanical signs and printing techniques.
The history isn’t entirely straightforward. Unlike vacuum tubes or transistors, segmented displays evolved gradually through a series of practical ideas rather than one defining invention.
While looking into the history of segmented displays, I was reminded of something I’d seen years ago in retail stores: reusable price tags printed with rows of eights.
Rather than printing every possible price, the clerk simply used a marker to black out portions of each figure, transforming an 8 into whatever digit was needed. Cover a few strokes, and the eight becomes a three. Remove a different set, and it becomes a zero or a five. It was, in essence, a manual segmented display.
Finding the exact origin of these price tags is akin to finding out where Romans bought sponges. They were inexpensive commercial supplies, not the sort of products that historians carefully documented. My recollection is from the middle of the twentieth century, but the underlying concept is almost certainly older.
George Mason’s 1898 21-segment display used 21 lamps and a complicated switch to display any digit or letter in a very stylish font. You can see a modern recreation of these ancient displays in the video below. While this is the basic idea, certainly, it is more ambitious than a simple 7-segment display.
I couldn’t determine that Mason’s displays were ever used for anything.
You could argue that an early 1903 invention by Carl Kinsley to draw characters telegraphically using six pens was an even better precursor, but using magnets to draw with pens on tapes hardly seems to qualify as a display, although figure 12 in the patent clearly shows the formation of numbers and even letters with this arrangement.
The direct parent of modern segmented digit displays appeared in the early 1900s (filed 1908; granted in 1910). Technically, this was an 8-segment display because it had a bar dedicated to forming a proper four, with the top-left part slanted. But removing that one segment is just an optimization. It may or may not have been the first, but by 1910, seven-segment displays were in use and not just curiosities on a workbench or dreams in a patent application.
Even for lit-up displays, the first implementations weren’t LEDs. Early displays used incandescent lamps or neon-filled tubes. By the 1930s and 1940s, segmented neon or incandescent indicators were appearing in industrial equipment and counters, instead of the common columns of ten neon bulbs, pointers, or rotating wheels.
Then, too, there were different approaches. Nixie tubes used individual character forms that lit up. Decatrons could count with ten different glowing points, each representing a digit.
The real explosion came in the late 1960s when practical LED displays arrived. Suddenly, segmented displays could be compact, rugged, inexpensive, and operate at low voltages. Calculators, clocks, frequency counters, digital multimeters, and every imaginable piece of consumer electronics adopted them almost overnight.
Of course, it wasn’t just LEDs. Numitrons used seven tiny incandescent filaments. Vacuum fluorescent displays used segments with phosphor that glowed when excited. LCDs adopted the same pattern, blocking or passing light to produce the segments. But the key idea was something that lights up, arranged in seven segments.
Early LED displays often had all the diodes on a single die to reduce cost. That made them very tiny. It wasn’t unusual to see displays with magnifying bubbles to make it easier to read.
The important point isn’t whether they used exactly seven segments. Many didn’t. Some divided the numerals differently or used additional pieces to produce more attractive typography. The insight was the same: begin with the most complex digit and selectively remove strokes to create all the others.
One of the reasons seven segments became the standard is that they strike a perfect balance (although not everyone agrees, as you can see in the video below). With fewer than seven elements, several decimal digits become difficult to distinguish. Adding more segments certainly improves appearance, but every additional segment increases wiring, decoding logic, manufacturing cost, and the number of possible failure points. Seven is the right number for — um — numbers. But what about letters?
You can make some compromises to show some letters. For example, old computers would display hex digits using seven segments, but the A would be uppercase and the B would be lowercase. You also had to light the top segment for the 6 to make it look different from a B. But you only need A-F for hex. If you need, say, the letter S, there’s no real way to make it not look like a 5 with 7 segments. But sometimes, the letters you can make are good enough.
There were also 8- and 9-segment displays that could do better with letters and special characters. You can increase the segments further to get more glyphs.
Today, you have a plethora of options for adding alphanumeric screens to just about anything. Yet, you still see 7-segment displays hanging around.
The seven-segment display isn’t successful because it’s beautiful. It isn’t even especially flexible. It’s successful because it’s close to the minimum solution that works. It delivers readable numbers with very little hardware, whether the technology behind it is incandescent bulbs, neon, vacuum fluorescence, LEDs, LCDs, or even ink on a printed price tag.
Perhaps that’s why it has survived every technological transition for more than a hundred years. Good engineering ideas often outlive the technologies that first bring them to life.
And once you start looking for segmented displays, you’ll notice they’ve been hiding in plain sight for much longer than the digital age.
Featured image: [Arduino Enigma]’s marvelous Seven Segment Art Installation
We know, we know. Despite being called ESP32-Plane-Radar, this project from [Mateusz Juszczyk] isn’t actually using radar. But thanks to the round LCD this desktop gadget does a fantastic job of recreating a classic radar display, and by pulling in Automatic Dependent Surveillance–Broadcast (ADS-B) data, the visuals even match nearby real-world aircraft.
Perhaps the best part of this project is just how easy it is for others to get in on the action. Although the presentation certainly looks professional — and expensive, if we’re being honest — there’s nothing particularly exotic going on here. Specifically, there’s ESP32-C3 Super Mini behind the scenes cranking through the ADS-B data and pushing it out to a circular GC9A01 display. A minimalistic 3D printed enclosure holds both components, and while it’s undeniably slick as-is, we can’t help but think there’s potential here for more elaborate designs.
As you probably guessed from the lack of a radio in the parts list, the code [Mateusz] provides doesn’t actually sniff ADS-B out of the air. It connects to the local network over WiFi, and then hits adsb.fi to pull in crowdsourced flight data. Since the device has to connect to the network anyway, the code also offers up a web-based configuration interface which puts a little more polish on what’s already an impressive presentation.
We used a round GC9A01 display on the Vectorscope back in 2023, so if anyone ports this over to their old Supercon badge we’d love to see it in action.
Thanks to [Mauricio] for the tip.
We all know the e-ink persistent displays, as they’re cheap and plentiful enough to have become ubiquitous in applications such as supermarket price labels. But we don’t often see some of the other technologies that almost did the same thing. The BBC Archive has a report from 1986 showing one of them, a prototype display from STC.
E-ink relies on flipping the arrangement of black and white particles in its pixels, while this one has a fluid in which the molecules are aligned to let light through, or dispersed randomly, at which point they block light. Frustratingly, we aren’t told what the liquid is, but we are given what might be the reason that we’ve never seen one. The activation voltage is rather high at 200 volts. It’s still a fascinating glimpse of something we might have had, with some tasty early-PC-era portables along the way.
The BBC archive has served up quite a bit of retro goodness over time, and we’ve certainly featured one or two of them over time. A recent one was this demonstration of email via a flight to Amsterdam, from the same year as today’s display.
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