A Strange Display Gives Up Its Secrets

Providing a display for a project in 2020 is something of a done deal. Standard interfaces and off-the-shelf libraries for easily available and cheap modules mean that the hardest choice you’ll have to make about a display will probably relate to its colour. Three decades ago though this was not such a straightforward matter though, and having a display that was in any way complex would in varying proportion take a significant proportion of your processing time , and cost a fortune. [AnubisTTP] has an unusual display from that era, a four-digit LED dot matrix module, and the take of its reverse engineering makes for a fascinating read.

The LITEF 104267 was made in 1986, and is a hybrid circuit in a metal can with four clear windows , one positioned over each LED matrix. Inside are seven un-encapsulated chips alongside the LED matrices on a golf plated hybrid substrate. The chips themselves are not of a particularly high-density process, so some high-resolution photography was able to provide a good guess at their purpose. A set of shift registers drive the columns through buffers, while the rows are brought out to a set of parallel lines. Thus each column can be illuminated sequentially with data presented on the rows. It’s something that would have saved a designer of the day a few extra 74-series chips, though we are guessing at some significant cost.

This display may seem antiquated to us today, but it wasn’t the only option for 1980s designers. There’s one display driver from back then that’s very much still with us today.

Take Security Up A Notch By Adding LEDs

All computers are vulnerable to attacks by viruses or black hats, but there are lots of steps that can be taken to reduce risk. At the extreme end of the spectrum is having an “air-gapped” computer that doesn’t connect to a network at all, but this isn’t a guarantee that it won’t get attacked. Even transferring files to the computer with a USB drive can be risky under certain circumstances, but thanks to some LED lights that [Robert Fisk] has on his drive, this attack vector can at least be monitored.

Using a USB drive with a single LED that illuminates during a read OR write operation is fairly common, but since it’s possible to transfer malware unknowingly via USB drives, one that has a separate LED specifically for writing operations will help alert a user to any write operations that might be trying to fly under the radar. A recent article by [Bruce Schneier] pointed out this flaw in USB drives, and [Robert] was up to the challenge. His build returns more control to the user by showing them when their drive is accessed and in what way, which can also be used to discover unique quirks of one’s chosen operating system.

[Robert] is pretty familiar with USB drives and their ups and downs as well. A few years ago he built a USB firewall that was able to decrease the likelihood of BadUSB-type attacks. Be careful going down the rabbit hole of device security, though, or you will start seeing potential attacks hidden almost everywhere.

A Supercapacitor Might Just Light Your Way One Day

Sometimes the simplest hacks are the most useful ones, and they don’t come much simpler than the little supercapacitor LED flashlight from serial maker of cool stuff [Jeremy S. Cook]. Little more than an LED, a supercapacitor, USB plug, and couple of resistors, it makes a neat little flashlight that charges from any USB A power socket and delivers usable light for over half an hour.

It’s neat, but on its own there’s not much to detain the reader until it is revealed as a “Hello World” supercapacitor project from an article in which he delves into the possibilities of these still rather exotic components. Its point is to explore their different properties when compared to a battery, for example a linear voltage drop in contrast to the sharp drop-off of a chemical cell. In the video below the break we see him try a little boost regulator to deliver a constant voltage, with consequent severe loss of lighting time for the LED. It’s by this type of experimentation that we learn our way around a component unfamiliar to us, and the article and video are certainly worth a look if you’ve never used a supercapacitor before.

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A Simple POV Globe Via APA102

POV builds come in all shapes and sizes, and typically rely on LEDs for their high light output and fast response time. With this in mind, [Great Scott] grabbed some LED strip off the shelf and set about whipping up a POV LED globe.

Being a spinning POV build, it’s necessary to consider how to get power to the rotating elements. [Great Scott] decided to go with a simple solution of putting a LiPo battery on the rotating assembly, which runs the LEDs and Arduino Nano at the heart of the operation. The LEDs in question are of the APA102 type, making them readily addressable and capable of a wide color gamut. It’s all spun by a simple brushed DC motor, running from a separate supply at the base of the platform.

It’s very much a hacker build, held together with duct tape and zipties. Despite this, it looks tidy when in operation, as all of the important hardware is hidden at the centre of the globe. There’s a bit of a vibration problem, but [Great Scott] reckons this can be fixed with some frame modifications.

We’d love to see the build run some more advanced operations, like a representation of the Earth, or some kind of sun clock. If you’re interested in learning more about POV displays, we’ve got the primer you need. Video after the break.

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Diurnal Reef Control Realistically Insolates Your Aquarium

[Phillip]’s project is not just great for learning new words, it also shows just how complex natural systems can be. 

As we know from news around the word, reefs are delicate systems prone to damage from just about any imaginable threat. Escaped aquarium fish, sunscreen, and the wayward feet of well meaning tourists to name a few. So it’s no wonder that aquarium hobbyists sometimes go to incredible lengths to simulate the natural environments these creatures live in.

While [Phillip] is still tinkering with his designs for this project, we found the data he included really interesting. His goal is to be able to plug in any coordinate on the earth and have the lights replicate the location. That includes not just the sun, but also the light from the moon as many corals seem to only spawn during certain tides. Of course no LED is perfect so he’s even experimenting with putting light sensors under the water to provide a feedback loop to make it perfect.

We really like the ambition of this project and we hope he continues.

The Fun Is On The Christmas Tree With This Playable Duck Hunt Decoration

‘Tis the season for leftovers, be they food, regifted presents, or the decorations left behind in the wake of the festivities. Not to mention the late tips we get for holiday-themed builds, like this Duck Hunt ornament that’s completely playable.

Details are sparse in [wermy]’s video below, but there’s enough there to get the gist. The game is based on the Nintendo classic, where animated ducks fly across the screen and act as targets for a light pistol. Translating that to something suitable for decorating a Christmas tree meant adding an Arduino and an IR LED to the original NES light pistol, and building a base station with a Feather and a small LCD screen into a case that looks like [The Simpsons] TV. An LED on each 3d-printed duck target lights in turn, prompting you to blast it with the gun. An IR sensor on each duck registers hits, while the familiar sound effects are generated by the base, which also displays the score. Given a background of festive blinkenlights, it’s harder than it sounds – see it in action briefly below.

[wermy] has done some interesting builds before, like a RetroPie in an Altoids tin and a spooky string of eyes for Halloween. We hope he’ll come through with a more detailed build video for this project at some point – we’re particularly interested in those beautiful multi-color 3D-prints.

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PoE Powers Christmas Lights, But Opens Up So Much More

Addressable LEDs are a staple of homemade Christmas decorations in our community, as is microprocessor control of those LEDs. So at first sight [Glen Akins]’ LED decorated Christmas tree looks pretty enough, but isn’t particularly unusual. But after reading his write-up you’ll discover there’s far more to the project than meets the eye, and learn a lot about the technologies behind it that has relevance far beyond a festive light show.

The decoration is powered exclusively from power-over-Ethernet, with a PIC microcontroller translating Art-Net DMX-over-Ethernet packets into commands for the LED string. The control board is designed from the ground up and includes all the PoE circuitry, and the write-up  gives a very thorough introduction to this power source that takes the reader way beyond regarding PoE as simply another off-the-shelf black box. Along the way we see all his code, as well as learn a few interesting tidbits such as the use of a pre-programmed EEPROM containing a unique MAC address.

So if your house has CAT5 wiring and you want an extra dimension to your festive splendour, you’ve officially got a whole year to build your own version. He’s featured here before, with his buzzer to break the Caps Lock habit.

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