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.

Several shirts side by side, each with a custom design

3D Print A Custom T-Shirt Design, Step-by-Step

October 15, 2021 by Donald Papp 14 Comments

Want to make a t-shirt with a custom design printed on it? It’s possible to use a 3D printer, and Prusa Research have a well-documented blog post and video detailing two different ways to use 3D printing to create colorful t-shirt designs. One method uses a thin 3D print as an iron-on, the other prints directly onto the fabric. It turns out that a very thin PLA print makes a dandy iron-on that can survive a few washes before peeling, but printing flexible filament directly onto the fabric — while more complicated — yields a much more permanent result. Not sure how to turn a graphic into a 3D printable model in the first place? No problem, they cover that as well.

Making an iron-on is fairly straightforward, and the method can be adapted to just about any printer type. One simply secures a sheet of baking paper (better known as parchment paper in North America) to the print bed with some binder clips, then applies glue stick so that the print can adhere. A one- or two-layer thick 3D print will stick to the sheet, which can then be laid print-side down onto a t-shirt and transferred to the fabric by ironing it at maximum temperature. PLA seems to work best for iron-ons, as it preserves details better. The results look good, and the method is fairly simple.

Direct printing to the fabric with flexible filament can yield much better (and more permanent) results, but the process is more involved and requires 3D printing a raised bed adapter for a Prusa printer, and fiddling quite a few print settings. But the results speak for themselves: printed designs look sharp and won’t come loose even after multiple washings. So be certain to have a few old shirts around for practice, because mistakes can’t be undone.

A very thin 3D print makes a decent iron-on that survives a few washes.

A 3D-printed bed adapter enables direct printing onto fabric for better results.

That 3D printers can be used to embed designs directly onto fabric is something many have known for years, but it’s always nice to see a process not just demonstrated as a concept, but documented as a step-by-step workflow. A video demonstration of everything, from turning a graphic into a 3D model to printing on a t-shirt with both methods is all in the short video embedded below, so give it a watch.

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Software Removes The Facebook From Facebook’s VR Headset (Mostly)

October 13, 2021 by Donald Papp 18 Comments

It’s not a jailbreak, but [basti564]’s Oculess software nevertheless allows one the option to remove telemetry and account dependencies from Facebook’s Oculus Quest VR headsets. It is not normally possible to use these devices without a valid Facebook account (or a legacy Oculus account in the case of the original Quest), so the ability to flip any kind of disconnect switch without bricking the hardware is a step forward, even if there are a few caveats to the process.

To be clear, the Quest devices still require normal activation and setup via a Facebook account. But once that initial activation is complete, Oculess allows one the option of disabling telemetry or completely disconnecting the headset from its Facebook account. Removing telemetry means that details about what apps are launched, how the device is used, and all other usage-related data is no longer sent to Facebook. Disconnecting will log the headset out of its account, but doing so means apps purchased from the store will no longer work and neither will factory-installed apps like Oculus TV or the Oculus web browser.

What will still work is the ability to sideload unsigned software, which are applications that are neither controlled nor distributed by Facebook. Sideloading isn’t on by default; it’s enabled by putting the headset into Developer Mode (a necessary step to installing Oculess in the first place, by the way.) There’s a fairly active scene around unsigned software for the Quest headsets, as evidenced by the existence of the alternate app store SideQuest.

Facebook’s control over their hardware and its walled-garden ecosystem continues to increase, but clearly there are people interested in putting the brakes on where they can. It’s possible the devices might see a full jailbreak someday, but even if so, what happens then?

Front view of vintage radio, with small screen inset into tuner.

Vintage Radio Gets Internet Upgrade

October 12, 2021 by Donald Papp 14 Comments

There’s nothing quite like vintage hardware, and the way it looks and works is something that can be worth celebrating. [Old Tech. New Spec] did that with his loving modification of a 1964 Dansette portable radio, bringing it into the modern era by giving it the ability to play Internet radio stations while keeping all the original controls and appearance. As he says, you’d hardly know it has been modified unless you turned it on.

Internet radio station logos scrolling across small LCD screen — A full color LCD behind a convex lens matches the radio’s aesthetic.

A real centerpiece of this conversion is that the inner part of the tuning dial has been replaced with a full color LCD display that shows, among other things, the logo of whatever Internet radio station is currently playing. The combination of LCD and convex lens looks fantastic, and blends beautifully into the aesthetic.

Inside the device is a Raspberry Pi, some simple Python scripts, and a Pirate Audio board. Together, they handle the job of audio streaming and output, displaying album art, and accepting inputs for playback controls. A large power bank ensures the result remains portable, and as usual with vintage hardware, there’s no worry about fitting everything inside. Watch it in action in the video embedded below. (And if the name of the audio board got you excited, but you’re disappointed to discover there’s no actual pirate broadcasting happening? Well, the Raspberry Pi can do that, too.)

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LED Matrix Hourglass Knows Which Way Is Up

October 8, 2021 by Donald Papp 6 Comments

[Fearless Night]’s slick dual hourglass doesn’t just simulate sand with LEDs, it also emulates the effects of gravity on those simulated particles and offers a few different mode options.

The unit uses an Arduino (with ATMEGA328P) and an MPU-6050 accelerometer breakout board to sense orientation and movement, and the rest is just a matter of software. Both the Arduino and the MPU-6050 board are readily available and not particularly expensive, and the LED matrix displays are just 8×8 arrays of red/green LEDs, each driven by a HT16K33 LED controller IC.

The enclosure and stand are both 3D-printed, and a PCB not only mounts the components but also serves as a top cover, with the silkscreen layer of the PCB making for some handy labels. It’s a clever way to make the PCB pull double-duty, which is a technique [Fearless Night] also used on their earlier optical theremin design.

Those looking to make one of their own will find all the design files and source code handily available from the project page. It might not be able to tell time in the classical sense, but seeing the hourglass displays react to the device’s orientation is a really neat effect.

Upside-down c-clamp held in a frame, forming a crude press

C-Clamp Becomes Light-Duty Arbor Press

October 7, 2021 by Donald Papp 8 Comments

[ThingaUser] made a tool to solve a specific problem of theirs, but the design also happens to be a pretty good way to turn a c-clamp into a poor man’s light duty arbor press.

The frame is made for a common 4-inch c-clamp.

The problem they had was a frequent need to press nuts and occasionally bearings into other parts. Some kind of press is really the best tool for the job, but rather than buy a press, they opted to make their own solution. By designing and 3D printing an adapter for a common 4-inch c-clamp, a simple kind of light duty press was born.

Sure, one has to turn the handle on the clamp to raise and lower the moveable jaw, and that’s not the fastest operation. But the real value in the design is that the clamp can now stand by itself on a tabletop, leaving the operator to dedicate one hand to manipulating the part to be pressed, while twisting the clamp’s handle with the other hand. There’s no need for a third hand to keep the clamp itself stable in the process. As a bonus, it can print without supports and the clamp secures with zip ties; no other fasteners or glue needed.

Not all c-clamps are the same, so there is a risk that this frame that fits [ThingaUser]’s clamp might not fit someone else’s. In those cases, it’s best to have access to not just the STL file, but also to a version in a portable CAD format like STEP to make it easy to modify. But there are still ways to make changes to an STL that isn’t quite right.

3D Printering: Corrugated Plastic For Cheaper & Easier Enclosures

October 6, 2021 by Donald Papp 37 Comments

Clear acrylic panels have long been a mainstay of 3D printer enclosure designs, but they can also add significant cost in terms of money, shipping, weight, and hassle. An alternative material worth looking at is corrugated plastic (also known by its trade name coroplast) which is cheap, light, an excellent insulator, and easy to work with. Many enclosure designs can be refitted to use it instead of acrylic, so let’s take a closer look at what it has to offer.

What’s Wrong With Acrylic?

It’s not just the purchase price that makes acrylic a spendy option. Acrylic is fairly heavy, and shipping pieces the size of enclosure panels can be expensive. Also, cutting acrylic without special tools can be a challenge because it cracks easily if mishandled. Acrylic cuts beautifully in a laser cutter, but most laser cutters accessible to a hobbyist are not big enough to make enclosure-sized panels. If you are stuck with needing to cut acrylic by hand, here are some tips on how to get by with the tools you have.

It is best to source acrylic from a local shop that can also cut it to size with the right tools for a reasonable price, but it is still far from being a cheap material. There’s another option: corrugated plastic has quite a few properties that make it worth considering, especially for a hobbyist.

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