A Laser With Mirrors Makes A CRT-like Display

November 26, 2024 by Maya Posch 22 Comments

[bitluni]’s laser-based display pretending to be a an old-school vector CRT.

Phosphor-based displays like CRTs rely on the phosphor to emit light for a set amount of time after being activated, allowing them to display a seemingly persistent image with one drawing beam per color. Translated to UV-sensitive PLA filament, this means that you can totally use a printed sheet of this material in combination with a 405 nm laser diode to create a display that doesn’t look dissimilar to an early CRT. This is exactly what [bitluni] did in a recent video, meshing together said laser diode, UV-sensitive PLA, stepper motors and two mirrors with an Arduino-based controller to create a rather interesting vector display.

In the video, [bitluni] goes over the development steps, including a range of improvements like being able to turn off the laser when moving between the end of a line and the beginning of a new one. While the Arduino Nano board does the driving of the stepper motor controllers, an ESP32 provides the drawing instructions. The STL and other project files including Nano & ESP32 firmware can be found on the GitHub project page.

While far from being a practical display with a single-digit Hz refresh rate, it does provide an interesting demonstration of these types of persistence of vision based displays, and without the use of exotic MEMS mirror modules or the like.

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A beige computer monitor with a green glow sits atop a flat, beige Apple IIc with a mouse next to it on a dark wooden table. A vase full of bright pink flowers is in the background.

G4 Mac Mini Is A Wolf In Apple IIc Clothing

September 15, 2024 by Navarre Bartz 4 Comments

Restomods let us relive some of the glory days of industrial design with internals that would blow the socks off the original device. [Mental Hygiene] decided to update an Apple IIc with a G4 brain.

Starting with a broken IIc, they pulled the internals, including the venerable 6502, and transplanted the parts from a G4 Mac mini into the case. There was plenty of room for the small desktop and its power supply. We love how they were able to repurpose the 5 1/4″ floppy access on the side of the IIc as a DVD drive.

The original keyboard was adapted with an Arduino Teensy into a USB unit for the mini, but the internals of the mouse were replaced with a modern USB laser mouse running the signals over the original connector. What really sells this particular restomod is the “VGA adapter that outputs monochrome NTSC via RCA” allowing a vintage Apple CRT to make this look like a device that somehow upgraded all the way to OSX.

This mod looks to be from 2012, so we’re wondering if it’s time someone did this with an Apple Silicon mini? We’ve previously covered a few different minis inside G4 iMacs. We’ve even seen someone tackle the Compact Macintosh with an iPad mini.

Designing For The Small Grey Screen

May 3, 2022 by Jenny List 23 Comments

With the huge popularity of retrocomputing and of cyberdecks, we have seen a variety of projects that use a modern computer such as a Raspberry Pi bathed in the glorious glow of a CRT being used as a monitor. The right aesthetic is easily achieved this way, but there’s more to using a CRT display than simply thinking about its resolution. Particularly a black-and-white CRT or a vintage TV has some limitations due to its operation, that call for attention to the design of what is displayed upon it. [Jordan “Ploogle” Carroll] has taken a look at this subject, using a 1975 Zenith portable TV as an example.

The first difference between a flat panel and a CRT is that except in a few cases it has a curved surface and corners, and the edges of the scanned area protrude outside the edges of the screen. Thus the usable display area is less than the total display area, meaning that the action has to be concentrated away from the edges. Then there is the effect of a monochrome display on colour choice, in other words the luminance contrast between adjacent colours must be considered alongside the colour contrast. And finally there’s the restricted bandwidth of a CRT display, particularly when it fed via an RF antenna socket, which affects how much detail it can reasonably convey. The examples used are games, and it’s noticeable how Nintendo’s design language works well with this display. We can’t imagine Nintendo games being tested on black-and-white TV sets in 2022, so perhaps this is indicative of attention paid to design for accessibility.

While they require a bit of respect due to the presence of dangerous voltages, there’s a lot of fun to be had bringing a CRT into 2022. Get one while you still can, and maybe you could have a go at a retro cyberdeck.