NES On RISC-V

March 14, 2019 by 19 Comments

RISC architecture might change the world, but it runs an NES emulator right now. That’s thanks to MaixPy, the new MicroPython for the K210, the recently released RISC-V microcontroller that’s making waves in the community. [Robot Zero One] has the tutorial and [Other Dave] of EEVBlog has a video of the thing in action.

The Sipeed K210 came to the English-speaking world in the form of a weird pre-order thing on Taobao last October promising a dual-core RISC-V CPU for just a few bucks. Seeed, the same people who brought the ESP8266 into mass distribution quickly latched on and started selling modules last February. Now, Seeed is looking at a Raspberry Pi hat using a Sipeed module, and the future for RISC-V microcontrollers is looking great. Now someone just needs to write some software. That’s exactly what the engineers at Sipeed did, and somewhere in one of the released binaries there’s an NES emulator.

The parallel to the question of if something can run Doom is if something can run an NES emulator, so with the release of MicroPython support for the K210, the obvious thing to do is to release an NES emulator. The hardware required is a Maix M1w Dock, available from Seeed and Banggood.

The new support for MicroPython is great, and an NES emulator is amazing, but this should really come as no surprise. From our first hands on with the first Open Source microcontroller two years ago, RISC-V was obviously faster. Now it’s cheap, and we can’t wait to see what’ll come next.

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Simple Sensor Provides Detailed Motion Capture For VR Hands

March 14, 2019 by 7 Comments

Consider the complexity of the appendages sitting at the end of your arms. The human hands contain over a quarter of the entire complement of bones in the body, use dozens of muscles both in the hand itself and extending up the forearm, and are capable of almost infinite variance in the movements they can create. They are exquisite machines.

And yet when it comes to virtual reality, most simulations treat the hands like inert blobs. That may be partly due to their complexity; doing motion capture from so many joints can be computationally challenging. But this pressure-sensitive hand motion capture rig aims to change that. The product of an undergraduate project by [Leslie], [Hunter], and [Matthew], the idea was to provide an economical and effective way to capture gestures for virtual reality simulators, which generally focus on capturing large motions from the whole body.

The sensor consists of a sandwich of polyurethane foam with strain gauge sensors embedded within. The user slips his or her hand into the foam and rests the fingers on the sensors. A Teensy and twenty lines of code translate finger motions within the sandwich into five axes of joystick movement, which is then sent to Unreal Engine, where finger motions were translated to a 3D-model of a hand to play a VR game of “Rock, Paper, Scissors.”

[Leslie] and her colleagues have a way to go on this; testers complained that the flat hand posture was unnatural, and that the foam heated things up quickly. Maybe something more along the lines of these gesture-capturing gloves would work?

Emulating An Altair 8800 On An Apple II

March 13, 2019 by 5 Comments

The Altair 8800 was, to its creators, a surprise hit. Despite looking nothing like what we would today consider to be a computer, it sold thousands of units almost immediately upon its launch, way back in 1975. A few years later, the Apple II burst onto the scene, and the home computer revolution began in earnest.

Emulating older machines on newer hardware has always been a thing, and [option8] has coded an Altair 8800 emulator for the Apple II. Of course, if you don’t have one lying around, you can run this emulator on an Apple II emulator right in your browser. Honestly, it’s emulators all the way down.

As far as emulators go, this is a particularly charming one, with the Altair’s front panel displayed in glorious color on the Apple’s 40 column screen. Replete with a full set of switches and blinking LEDs, it’s a tidy low-resolution replica of the real thing. Instructions to drive it are available, along with those for another similar emulator known as Apple80.

If that still hasn’t quenched your thirst, check out this Game Boy emulator that lives inside emacs.

ATtiny Gets A Tiny Software UART

March 13, 2019 by 27 Comments

Modern microcontroller platforms spoil us with their performance and expansive spec sheets. These days it’s not uncommon to be developing for a cheap micro that has a clock rate well in excess of 100MHz, with all manner of peripherals baked in. DACs, WiFi, you name it – it’s in there, with a bunch of libraries to boot. It wasn’t always this way, and sometimes you would even find yourself lacking hardware serial support. In these cases, the bitbanged software UART is your friend, and [MarcelMG] decided to document just how it’s done.

The amateur programmer’s first recourse may be to use delays to properly time the output data stream. This has the drawback of wasting processor cycles and doesn’t let the microcontroller do much else useful. Instead, [Marcel] discusses the proper way to do things, through the use of interrupt service routines and hardware timers.

[Marcel]’s implementation is for the ATtiny24A, though it should be easily portable to other AVR8 processors. Taking up just 2 bytes of RAM and 276 bytes of program space, it’s compact – which is key on resource-limited 8-bit devices. The code is available on Github if you fancy trying it out yourself.

It’s a technique that is more than familiar to the old hands, but useful to those new to the art. It can be particularly useful if you need to get data out of a legacy platform with limited options. As times change, it’s important to pass on the techniques of yesteryear to the new generation. Of course, if things are really tight, you can even do a half-duplex UART on a single pin.

 

3D Scanning Via DIY Photogrammetry

March 13, 2019 by 21 Comments

For those with 3D printers, taking a 3D model and spitting out a physical object is so routine as to be blasé. The reverse is something a little different. There are many ways to create a digital 3D model of a physical object, of varying complexity. [Eric Strebel] favors photogrammetry, and has shared a useful guide for those interested in using this technique.

In its most basic sense, photogrammetry refers to taking measurements from photographs. In the sense being discussed here, it more precisely refers to the method of creating a 3D model from a series of photographs of a physical object. By taking appropriate images of an object, and feeding them through the right software, it’s possible to create a digital representation of the object without requiring any special hardware other than a camera.

[Eric] shares several tips and tricks for getting good results. Surface preparation is key, with the aim being to create a flat finish to avoid reflections causing problems. A grey primer is first sprayed on the object, followed by a dusting of black spots, which helps the software identify the object’s contours. Camera settings are also important, with wide apertures used to create a shallow depth-of-field that helps the object stand out from the background.

With the proper object preparation and camera technique taken care of, the hard work is done. All that’s then required is to feed the photos through the relevant software. [Eric] favors Agisoft Metashape, though there are a variety of packages that offer this functionality.

We first reported on photogrammetry back in 2016. If cameras aren’t your thing, you can always give lasers a try. Video after the break.

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Do-It-Yourself Scratch Cards

March 13, 2019 by 15 Comments

The lottery is to some a potential bonanza, to others a tax on the poor and the stupid. The only sure-fire way to win a huge fortune in the lottery does remain to start with an even bigger fortune. Nevertheless, scratch-off tickets are the entertainment that keep our roads paved or something. [Emily] over on Instructables came up with a way to create your own scratch-off cards, and the process is fascinating.

For [Emily]’s scratchers, there are five layers of printing on the front of the card. From back to front, they are the gray ‘security confusion layer’ printed with a letterpress, black printing for the symbols and prize amounts, also printed on a letterpress, a scratch-off surface placed onto the card with a Silhouette cutter, the actual graphics on the card, printed in blue with a letterpress, and a final layer of clear varnish applied via screen printing. There’s a lot that goes into this, but the most interesting (and unique) layer is the actual scratch-off layer. You can just buy that, ready to cut on a desktop vinyl cutter. Who knew.

After several days worth of work, [Emily] had a custom-made scratcher, ready to sent out in the mail as a Christmas card. It’s great work, and from the video below we can see this is remarkably similar to a real scratch-off lottery ticket. Not that any of us would know what scratching a lottery ticket would actually be like; of course that’s only for the gullible out there, and of course none of us are like that, oh no. You can check out a video of the scratch-off being scratched off below.

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Become The Next Fabergé With A Rose Engine Lathe

March 13, 2019 by 12 Comments

The basics of a skill may take a long time to master, but there is always something else to learn about regardless of the craft. Building a piece of fine furniture out of hardwood or being able to weld together a bicycle from scratch are all impressive feats, but there are fine details that you’ll only learn about once you get to this level of craftsmanship. One such tool that will help with these intricacies is known as the rose engine lathe.

This tool is based on an average lathe, typically used for creating round things out of stock which is not round. A rose engine lathe has a set of cams on it as well which allow the lathe to create intricate patterns in the material it’s working with, such as flower type patterns or intricate spirals. One of the most famous implementations of this method was on the Fabergé eggs. While this might make it sound overly complex, this how-to actually shows you how to build your own rose engine lathe out of a piece of MDF and a large number of miscellaneous pieces of hardware.

We recently featured another build which performs a similar function called engine turning. While similar, this is the method responsible for creating overlapping spirals on a piece of metal. Either way, both projects are sure to spice up your metal or woodworking endeavors.

Thanks to [PWalsh] for the tip!