Rescuing High-Res Displays From Older Macs

September 10, 2024 by Bryan Cockfield 26 Comments

When Apple started rolling out its Retina displays, it multiplied the amount of pixels compared to their standard, non-Retina displays by four. This increased pixel density while keeping the standard screen size — idea for those needing a lot of detail for their work. But, as is common with Apple, using these displays outside of the Apple ecosystem can be quite a challenge. Retina displays have been around for about a decade now, though, with some third-party hardware able to break them free of their cage. This post details how [Kevin] liberated the 5K display from a 2017 iMac for more general use with support for USB-C.

The first step was to find a used iMac for the right price, and then sell off most of its parts to recoup most of the initial cost. That brought the cost of the panel itself to about $250. The key to getting the display working without all of the Apple hardware is the R1811 driver board, which can be had for around $300. A new 156 watt power supply was added to the mix, and [Kevin] also put in a few extras like a USB cable extension and a latching push-button which kills the display’s power. Additionally, he attempted to get the original iMac speakers working with this setup too, but none of his attempts resulted in anything close to quality sound so he’s mostly abandoned that extra feature for now.

With that all buttoned up, he has a 27″ 5K display with USB-C input for around $650 which is quite a deal. The MacRumors thread that [Kevin] added his project to currently has around 1,700 posts about similar builds too, so it can be a wealth of information for all kinds of models. As Apple drops support for their older machines, these displays will become more and more common and projects like these can keep a lot of e-waste out of the landfill while also providing decent hardware at a bargain price. Don’t just look for iMacs and MacBooks though; there’s a similar process to use various iPad displays for other things as well.

A Little Optical Magic Makes This Floating Display Pop

August 29, 2024 by Dan Maloney 4 Comments

If there’s a reason that fancy holographic displays that respond to gestures are a science fiction staple, it’s probably because our current display technology is terrible. Oh sure, Retina displays and big curved gaming monitors are things of wonder, but they’re also things that occupy space even when they’re off — hence the yearning for a display that can appear and disappear at need.

Now, we’re not sure if [Maker Mac70]’s floating display is the answer to your sci-fi dreams, but it’s still pretty cool. And, as with the best of tricks, it’s all done with mirrors. The idea is to use a combination of a partially reflective mirror, a sheet of retroreflective material, and a bright LCD panel. These are set up in an equilateral triangle arrangement, with the partially reflective mirror at the top. Part of the light from the LCD bounces off the bottom surface of the mirror onto a retroreflector — [Mac] used a sheet of material similar to what’s used on traffic signs. True to its name, the retroreflector bounces the light directly back at the semi-transparent mirror, passing through it to focus on a point in space above the whole contraption. To make the display interactive, [Mac] used a trio of cheap time-of-flight (TOF) sensors to watch for fingers poking into the space into which the display is projected. It seemed to work well enough after some tweaking; you can check it out in the video below, which also has some great tips on greebling, if that’s your thing.

We suspect that the thumbnail for the video is a composite, but that’s understandable since the conditions for viewing such a display have to be just right in terms of ambient light level and the viewer’s position relative to the display. [Mac] even mentions the narrow acceptance angle of the display, touting it as a potential benefit for use cases where privacy is a concern. In any case, it’s very different from his last sci-fi-inspired volumetric display, which was pretty cool too.

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Original Game Boy Gets Display “Upgrade”

August 13, 2024 by Bryan Cockfield 16 Comments

Before LCD and LED screens were ubiquitous, there was a time when the cathode ray tube (CRT) was essentially the only game in town. Even into the early 2000s, CRTs were everywhere and continuously getting upgrades, with the last consumer displays even having a semi-flat option. Their size and weight was still a major problem, though, but for a long time they were cutting edge. Wanting to go back to this time with their original Game Boy, [James Channel] went about replacing their Game Boy screen with a CRT.

The CRT itself is salvaged from an old video conferencing system and while it’s never been used before, it wasn’t recently made. To get the proper video inputs for this old display, the Game Boy needed to be converted to LCD first, as some of these modules have video output that can be fed to other displays. Providing the display with power was another challenge, requiring a separate boost converter to get 12V from the Game Boy’s 6V supply. After getting everything wired up a few adjustments needed to be made, and with that the CRT is up and running.

Unfortunately, there was a major speed bump in this process when [James Channel]’s method of automatically switching the display to the CRT let the magic smoke out of the Game Boy’s processor. But he was able to grab a replacement CPU from a Super Game Boy, hack together a case, and fix the problem with the automatic video switcher. Everything now is in working order for a near-perfect retro display upgrade. If you’d like to do this without harming any original hardware, we’ve seen a similar build based on the ESP32 instead.

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A Lenticular Clock Spells Out The Hours

July 24, 2024 by Jenny List 1 Comment

So many are the clock projects which cross the Hackaday threshold, that it’s very rare indeed to see something that hasn’t already been done. We think we’ve not seen a lenticular clock before though, and we’re thus impressed by this one produced by [Moritz Sivers].

You may well be familiar with lenticular images from toys and novelties, an animation is sliced into lines and placed behind an array of multi-faceted linear lenses. It gives the effect of movement as from different viewing angles a different frame of the animation is perceived. In this clock the animation is replaced by the clock digits, and by rotating the whole with a servo driven by an ESP8266 microcontroller it can display different digits to the viewer. The write-up and the video below are of value both for the clock itself and the description of how these animations are produced. The clock itself doesn’t sacrifice usability for all its novelty, and we can see this technique might find a place in other projects requiring custom displays.

The lenticular lenses used here are off the shelf, but if you are of an adventurous mind, you could try printing some of your own.

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Go Forth With This Portable Programmer

June 29, 2024 by Bryan Cockfield 14 Comments

When choosing a low-level language, it’s hard to beat the efficiency of Forth while also maintaining some amount of readability. There are open source options for the language which makes it accessible, and it maintains its prevalence in astronomical and other embedded systems for its direct hardware control and streamlined use of limited resources even though the language started over 50 years ago. Unlike 50 years ago, though, you can now take your own self-contained Forth programmer on the go with you.

The small computer is built on a design that [Dennis] built a while back called my4TH which has its own dedicated 8-bit CPU and can store data in a 256 kB EEPROM chip. Everything else needed for the computer is built in as well but that original design didn’t include a few features that this one adds, most notably a small 40×4 character LCD and a keyboard. The build also adds a case to tie everything together, with ports on the back for I2C and power plus an RS232 port. An optional battery circuit lets the computer power up without an external power supply as well.

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An Easy Transparent Edge Lit Display

June 24, 2024 by Dave Rowntree 20 Comments

Displays are crucial to modern life; they are literally everywhere. But modern flat-panel LCDs and cheap 7-segment LED displays are, well, a bit boring. When we hackers want to display the progress of time, we want something more interesting, hence the plethora of projects using Nixie tubes and various incantations of edge-lit segmented units. Here is [upir] with their take on the simple edge-lit acrylic 7-segment design, with a great video explanation of all the steps involved.

Engraving the acrylic sheets by hand using 3D printed stencils

The idea behind this concept is not new. Older displays of this type used tiny tungsten filament bulbs and complex light paths to direct light to the front of the display. The modern version, however, uses edge-lit panels with a grid of small LEDs beneath each segment, which are concealed within a casing. This design relies on the principle of total internal reflection, created by the contrast in refractive indices of acrylic and air. Light entering the panel from below at an angle greater than 42 degrees from normal is entirely reflected inside the panel. Fortunately, tiny LEDs have a wide dispersion angle, so if they are positioned close enough to the edge, they can guide sufficient light into the panel. Once this setup is in place, the surface can be etched or engraved using a CNC machine or a laser cutter. A rough surface texture is vital for this process, as it disrupts some of the light paths, scattering and directing some of it sideways to the viewer. Finally, to create your display, design enough parallel-stacked sheets for each segment of the display—seven in this case, but you could add more, such as an eighth for a decimal point.

How you arrange your lighting is up to you, but [upir] uses an off-the-shelf ESP32-S3 addressable LED array. This design has a few shortcomings, but it is a great start—if a little overkill for a single digit! Using some straightforward Arduino code, one display row is set to white to guide light into a single-segment sheet. To form a complete digital, you illuminate the appropriate combination of sheets. To engrave the sheets, [upir] wanted to use a laser cutter but was put off by the cost. A CNC 3018 was considered, but the choice was bewildering, so they just went with a hand-engraving pick, using a couple of 3D printed stencils as a guide. A sheet holder and light masking arrangement were created in Fusion 360, which was extended into a box to enclose the LED array, which could then be 3D printed.

If you fancy an edge-lit clock (you know you do) check out this one. If wearables are more your thing, there’s also this one. Finally, etched acrylic isn’t anywhere near as good as glass, so if you’ve got a vinyl cutter to hand, this simple method is an option.

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Learning Morse Code With A DIY Trainer

June 22, 2024 by Bryan Cockfield 17 Comments

Morse code, often referred to as continuous wave (CW) in radio circles, has been gradually falling out of use for a long time now. At least in the United States, ham radio licensees don’t have to learn it anymore, and the US Coast Guard stopped using it even for emergencies in 1999. It does have few niche use cases, though, as it requires an extremely narrow bandwidth and a low amount of power to get a signal out and a human operator can usually distinguish it even if the signal is very close to the noise floor. So if you want to try and learn it, you might want to try something like this Morse trainer from [mircemk].

While learning CW can be quite tedious, as [mircemk] puts it, it’s actually fairly easy for a computer to understand and translate so not a lot of specialized equipment is needed. This build is based around the Arduino Nano which is more than up for the job. It can accept input from any audio source, allowing it to translate radio transmissions in real time, and can also be connected to a paddle or key to be used as a trainer for learning the code. It’s also able to count the words-per-minute rate of whatever it hears and display it on a small LCD at the front of the unit which also handles displaying the translations of the Morse code.

If you need a trainer that’s more compact for on-the-go CW, though, take a look at this wearable Morse code device based on the M5StickC Plus instead.

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