There was a time when no self-respecting electronics engineer would build a big project without at least one panel meter. They may be a rare part here in 2024, but we find ourselves reminded of them by [24Eng]’s project. It’s a 3D printed housing for one of those common small OLED displays, designed to be mounted on a panel with just a single round hole. Having had exactly this problem in the past trying to create a rectangular hole, we can immediately see the value in this.

It solves the problem by encasing the display in a printed shell, and passing a coarsely threaded hollow cylinder behind it for attachment to the panel and routing wires. This is where we are reminded of panel meters, many of which would have a similar sized protrusion on their rear housing their mechanism.

The result is a neatly made OLED display mounting, with a hole that’s ease itself to create. Perhaps now you’ll not be afraid to make your own panels.

This DIY lasertag project designed by [Nii], which he brought to Tokyo Maker Faire back in September, is a treasure trove. It’s all in Japanese and you’ll need to visit X (formerly Twitter) to see it, but the images do a fine job of getting the essentials across and your favorite translator tool will do a fair job of the rest.

There’s a whole lot to admire in this project. The swing-out transparent OLED display is super slick, the electronics are housed on a single PCB, the back half of the grip is in fact a portable USB power bank that slots directly in to provide power, and there’s a really smart use of a short RGB LED strip for effects.

The optical elements show some inspired design, as well. An infrared LED points forward, and with the help of a lens, focuses the beam tightly enough to make aiming meaningful. For detecting hits, the top of the pistol conceals a custom-made reflector that directs any IR downward into a receiver, making it omnidirectional in terms of hit sensing but only needing a single sensor.

Want to know more? Check out [Nii]’s earlier prototypes on his website. It’s clear this has been in the works for a while, so if you like seeing how a project develops, you’re in for a treat.

As for the choice of transparent OLED displays? They are certainly cool, and we remember how wild it looks to have several stacked together.

These days displays are increasingly expected to be bidirectional devices, accepting not only touch inputs, but also to integrate fingerprint sensing and even somehow combine a camera with a display without punching a hole through said display. Used primarily on smartphone displays, these attempts have been met with varying degrees of success, but a recently demonstrated version in Nature Communications which combines an OLED with photosensors in the same structure might provide a way to make such features much more effective.

The article by [Chul Kim] and colleagues of the Samsung Display Research Center in South Korea the construction of these bidirectional OLED displays is described, featuring the standard OLED pixels as well as an organic photodiode (OPD) placed side-by-side. Focusing on the OLED’s green light for its absorption characteristics with the human skin, the researchers were able to use the produced OLED/OPD hybrid display for fingerprint recognition, as well as a range of cardiovascular markers, including heart rate, blood pressure, etc.

The basic principle behind these measurements involves photoplethysmography, which is commonly used in commercially available pulse oximeters. Before these hybrid displays can make their way into commercial devices, there are still a few technical challenges to deal with, in particular electrical and optical leakage. The sample demonstrated appears to work well in this regard, but the proof is always in the transition from the lab to mass-production. We have to admit that it would be rather cool to have a display that can also handle touch, fingerprints and record PPG data without any special layers or sensor chips.