Unique Seven-Segment Display Relies On FR-4 Fluorescence

October 16, 2021 by Dan Maloney 11 Comments

It’s interesting what you see when you train a black light on everyday objects. We strongly suggest not doing this in a hotel room, but if you shine UV light on, say, a printed circuit board, you might see what [Sam Ettinger] did, which led him to build these cool low-profile seven-segment fluorescent PCB displays.

As it turns out, at least some FR-4 PCBs fluoresce under UV light, giving off a ghostly blue-green glow. Seeing the possibilities, [Sam] designed a PCB with cutouts in the copper and solder mask in the shape of a traditional seven-segment display. The backside of the PCB has pads for UV LEDs and current-limiting resistors, which shine through the board and induce the segments to glow. Through-slots between the segments keep light from one segment from bleeding over into the next; while [Sam] left the slots unfilled, they could easily be filled with solder. The fluorescent property of FR-4, and therefore the brightness and tint of the segments, seems to vary by board thickness and PCB manufacturer, but it looks like most PCBs will show pretty good results.

We’d say the obvious first improvement might be to cover the back of the display with black epoxy, to keep stray light down, and to improve contrast. But they look pretty great just as they are. We can also see how displays with other shapes, like icons and simple symbols. Or maybe even alphanumeric characters — say, haven’t we seen something like that before?

The Pi 400 As A PC Peripheral

October 16, 2021 by Jenny List 15 Comments

The Raspberry Pi 400 all-in-one computer is a neat little unit that is powerful enough to take on most humdrum computing tasks while doing an excellent job of freeing up valuable desktop space. But what about those moments when both the Pi and a PC are needed on the same desktop? How can the Pi and the bulky PC keyboard share the same space?

[Gadgetoid] may have the answer, with a clever bit of software that presents the Pi’s mouse and keyboard as peripherals on its USB-C power port. If your PC has a high-power USB socket that can run the Pi then it can use the small computer’s input devices just as well as the Pi itself can. It’s fair to say that the Pi 400’s keyboard is not it’s strongest point, but we can see some utility in the idea.

Running it is simply a case of running an executable from the Pi. Control can be wrested back to Raspberry Pi OS with a simple keystroke. Perhaps it’s not the ultimate desktop experience, but if you’re a die-hard Pi-head there’s plenty of appeal.

Within a few weeks, it’s a year since the launch of the Pi 400. We’ve not seen as many of them as the other Pi models, but you might find our original review to be of interest.

Thanks [Itay] for the tip.

Learn DMX512 Basics

October 15, 2021 by Al Williams 11 Comments

If you’ve done anything with modern lighting effects, you’ve probably heard of DMX, also known as DMX512. Ever wonder what’s really happening under the hood? If so, then you should have a look at [EEForEveryone’s] video on the topic, which you can see below.

At the core, the DMX512 uses RS485, but adds software layers and features. The video uses the OSI model to show how the system works.

Continue reading “Learn DMX512 Basics” →

Better History Through X-Rays

October 15, 2021 by Al Williams 7 Comments

Even if you aren’t a giant history buff, you probably know that the French royal family had some difficulties in the late 1700s. The end of the story saw the King beheaded and, a bit later, his wife the famous Marie Antoinette suffered the same fate. Marie wrote many letters to her confidant, and probable lover, Swedish count Axel von Fersen. Some of those letters have survived to the present day — sort of. An unknown person saw fit to blot out parts of the surviving letters with ink, rendering them illegible. Well, that is, until now thanks to modern x-ray technology.

Anne Michelin from the French National Museum of Natural History and her colleagues were able to foil the censor and they even have a theory as to the ink blot’s origin: von Fersen, himself! The technique used may enable the recovery of other lost portions of historical documents and was published in the journal Science Advances.

Continue reading “Better History Through X-Rays” →

OAK-D Depth Sensing AI Camera Gets Smaller And Lighter

October 15, 2021 by Donald Papp 9 Comments

The OAK-D is an open-source, full-color depth sensing camera with embedded AI capabilities, and there is now a crowdfunding campaign for a newer, lighter version called the OAK-D Lite. The new model does everything the previous one could do, combining machine vision with stereo depth sensing and an ability to run highly complex image processing tasks all on-board, freeing the host from any of the overhead involved.

Animated face with small blue dots as 3D feature markers. — An example of real-time feature tracking, now in 3D thanks to integrated depth sensing.

The OAK-D Lite camera is actually several elements together in one package: a full-color 4K camera, two greyscale cameras for stereo depth sensing, and onboard AI machine vision processing with Intel’s Movidius Myriad X processor. Tying it all together is an open-source software platform called DepthAI that wraps the camera’s functions and capabilities together into a unified whole.

The goal is to give embedded systems access to human-like visual perception in real-time, which at its core means detecting things, and identifying where they are in physical space. It does this with a combination of traditional machine vision functions (like edge detection and perspective correction), depth sensing, and the ability to plug in pre-trained convolutional neural network (CNN) models for complex tasks like object classification, pose estimation, or hand tracking in real-time.

So how is it used? Practically speaking, the OAK-D Lite is a USB device intended to be plugged into a host (running any OS), and the team has put a lot of work into making it as easy as possible. With the help of a downloadable application, the hardware can be up and running with examples in about half a minute. Integrating the device into other projects or products can be done in Python with the help of the DepthAI SDK, which provides functionality with minimal coding and configuration (and for more advanced users, there is also a full API for low-level access). Since the vision processing is all done on-board, even a Raspberry Pi Zero can be used effectively as a host.

There’s one more thing that improves the ease-of-use situation, and that’s the fact that support for the OAK-D Lite (as well as the previous OAK-D) has been added to a software suite called the Cortic Edge Platform (CEP). CEP is a block-based visual coding system that runs on a Raspberry Pi, and is aimed at anyone who wants to rapidly prototype with AI tools in a primarily visual interface, providing yet another way to glue a project together.

Earlier this year we saw the OAK-D used in a system to visually identify weeds and estimate biomass in agriculture, and it’s exciting to see a new model being released. If you’re interested, the OAK-D Lite is available at a considerable discount during the Kickstarter campaign.

Here’s A 100 MHz Pin-Compatible 6502 Replacement

October 15, 2021 by Lewin Day 94 Comments

The MOS Technology 6502 CPU was a popular part in its day. In various modified versions, it powered everything from the Commodore 64 to the Nintendo Entertainment System, and showed up in a million other applications too. A popular variant is the 65C02, and [Jürgen] decided to whip up a pin-compatible FPGA version that runs at a blazing 100MHz.

The CPU core was borrowed from work by [Arlet Ottens] and extended with 65C02 functionality by [Ed Spittles] and [David Banks]. [Jürgen] then packaged that core in a Spartan-6 FPGA and placed it on a small PCB the size of the original 65C02’s 40-pin dual inline package.

The FPGA is set up to access the external CPU bus with the timing matched to the clock of the host machine. However, internally, the CPU core runs at 100MHz. It copies RAM and ROM from the host machine into its own internal 64 kilobyte RAM, minus the areas used for memory-mapped I/O by the host. The CPU then runs at full 100MHz speed except when it needs to talk to those I/O addresses.

It allows the chip to accelerate plenty of tasks without completely flipping out when used with older hardware that can’t run at anywhere near 100MHz. The pin-compatible design has been tested successfully in an Apple II and a Commodore 8032, as well as a variety of vintage chess computers.

We’ve seen the opposite before too, with a real 6502 paired with a FPGA acting as the rest of the computer. If you’ve got any cutting-edge 6502 hacks of your own (not a misprint!), let us know!

[Thanks to David Palmer for the tip]

Hackaday Remoticon: Call For Proposals Extended To October 20th

October 15, 2021 by Kristina Panos No comments

In just a few short weeks, we’ll all be meeting up online for the second Hackaday Remoticon on November 19th and 20th. This is the year of the Talk, and who better than you, dear reader, to give one? Good news — we’ve extended the deadline for proposals to Wednesday, October 20th. We’ve all got at least one or two subjects that we could happily bloviate about for hours, be it hardware, software, skill sets, or the stuff that inspires you to stop dreaming and start doing. Why not share your wit and wisdom with the rest of the community?

So, what are you waiting for? Submit your talk proposal today! We’re not looking for you to pack the whole talk into the description box, but we would like to know what your talk will be about, and why it’s relevant to an audience of geeks, hackers, and engineers. Talks are typically 30 minutes in length, but we can likely accommodate shorter or longer talks if needed.

Everyone has something worth sharing, and the fact is, we are always looking for first-time speakers to showcase. Just share the things you’re doing that you’re passionate about, and you’re bound to have a great talk that generates excitement all around.

So grab some go-juice and start brainstorming the outline of your talk — give us enough information that we’ll be thirsty for more. Have you got terrible stage fright? Then encourage your outgoing hackerspace buddy to give one and cheer from the sidelines. Although we would rather see all of you in person, moving this conference online comes with the flexibility to hear from hackers all over the world, and no one has to leave home.