Speeding Up Drawing To MCU-Connected Serial Displays

Writing image data to serially connected (SPI/I2C) displays from a microcontroller is easy enough these days, courtesy of standards defined by the MIPI Alliance, yet there are some gotchas in it which may catch someone using it unaware. [Larry Bank] wrote up a good summary of how one can get maximum performance out of such a display link.

At the core is the distinction between pixel data and command transmissions. The change from command to pixel data mode requires signaling, which takes precious clock cycles away from transferring pixel data between the MCU and display. The common MIPI DCS instruction set allows for a big reduction in needed data transfers by allowing parts of the display to be addressed instead of requiring a full refresh. Yet by not properly segmenting command and data transfers, one ends up unnecessarily slowing down the process.

The result is that one can run something like a Pac-Man emulator on an AVR MCU with a sluggish 320×480 SPI LCD at 60 FPS, as one can see in the video that is embedded after the break. Check the article for another demo video as well.

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Windows 3.1 Screensavers, Now On Twitter

Back in the early dawn of the GUI age, cathode ray tubes were the dominant display technology for the personal computer. In order to avoid burn-in of static display elements, screensavers were devised to help prevent this problem. Out of love for the software of yesteryear, [Greg Kennedy] has put together a bot that posts Windows 3.1 screensavers on Twitter.

A Perl script runs the show in this case. Screensavers are packed into “units”, which are loaded by the script. A basic Windows 3.1 environment is then configured, and loaded into a specially patched DOSBOX that allows automated demo recording in a headless environment. Once up and running, video is recorded of the desktop and subsequent triggering of the screensaver. After a couple of minutes, the recording is stopped, and FFMPEG is used to transcode the video into a Twitter-suitable format. It’s then a simple job of Tweeting the video using the standard API.

It’s a fun project that makes sharing old screensavers easy. Be sure to check out the Twitter feed @dot_scr. If you’re addicted to the vintage aesthetic, try this Apple ][ screensaver hack on your Linux boxen. Video after the break.

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The Miniware TS100 As A USB-C Soldering Iron

Many readers will be familiar with the Miniware TS100 soldering iron, a lightweight temperature-controlled iron that is giving significantly more expensive soldering tools a run for their money. There is another model in the range, the TS80, which though it uses different tips than its sibling has the main distinguishing feature of USB-C power rather than a DC barrel jack. A cadre of users still prefer the TS100 for this reason, as an iron that can run from almost any low voltage DC power source. Any except USB-C, that is, an omission that [thinkl33t] has rectified with a USB-C adapter for the older model.

To achieve this, he’s used a readily-available ZYPDS USB-to-DC module and attached it to a barrel jack. For now, it’s simply held on by solder with a bit of heat-shrink over the top. [Thinkl33t] observes that this may not prove to be strong enough and he’ll eventually have to put it on a bit of cable. It’s a simple enough hack, but it serves as a quick introduction to these parts which perform the necessary USB-C magic to deliver a DC supply, as well as to highlight the relative scarcity of higher-power USB supplies.

At the moment there’s an inevitable move to USB-C All The Things, but it’s a trend that it seems many manufacturers of power sources have yet to catch up with. When a typical TS-80 owner finds their shiny new USB-C battery bank is, in reality, an older 5V USB bank with a USB-C connector fitted, it’s no wonder that their friends prefer the TS100. We hope that coming years will see a greater range of USB-C power options, but until then we like the versatility of the barrel jack on the TS100. Especially now that it can so readily be made to take USB-C power.

We reviewed the TS100 back in 2017, and two years of using it since then have not changed our opinion of it.

Thanks to the several tipsters including [thinkl33t]  himself who sent us this.

Control Lighting Effects Without Programming

Working in a theater or night club often requires a specialized set of technical skills that you might not instantly think about. Sure, the audio system needs to be set up and managed but the lighting system is often actively managed as well. For simple setups, this is usually not too difficult to learn. With more complicated systems you will need to get elbow-deep into some software. With [trackme518]’s latest tool, though, you will only need to be able to edit video.

Sure, this sounds like just trading one piece of software for another, but it’s more likely that professionals working in lighting will already know how to edit video rather than know programming or complicated proprietary lighting software. All you have to do to control a set of lights is to create a video, or use an existing one, and the lighting system will mimic the video on its own. If you do know programming, though, it’s written in Processing Java so changes aren’t too difficult to make.

The software (available on the project’s GitHub page) will also work outside of a professional environment, as well. It’s set up to work with DMX systems as well as LED strips so you could use it to run a large LED display board using only an input video as control. You could even use it to run the display on your guitar.

Photo courtesy of Rob Sinclair (Gribiche) [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)]

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Hackaday Links: September 22, 2019

Of all the stories we’d expect to hit our little corner of the world, we never thought that the seedy doings of a now-deceased accused pedophile billionaire would have impacted the intellectual home of the open-source software movement. But it did, and this week Richard Stallman resigned from the Computer Science and Artificial Intelligence Lab at MIT, as well as from the Free Software Foundation, which he founded and served as president. The resignations, which Stallman claims were “due to pressure on MIT and me over a series of misunderstandings and mischaracterizations”, followed the disclosure of a string of emails where he perhaps unwisely discussed what does and does not constitute sexual assault. The emails were written as a response to protests by MIT faculty and students outraged over the university’s long and deep relationship with Jeffrey Epstein, the late alleged pedophile-financier. This may be one of those stories where the less said, the better. If only Stallman had heeded that advice.

They may be the radio stations with the worst programming ever, but then again, the world’s atomic clock broadcasting stations can really keep a beat. One of the oldest of these stations, WWV, is turning 100 this year, and will be adding special messages to its usual fare of beeps and BCD-encoded time signals on a 100-Hz subcarrier. If you tune to WWV at 10 past the hour (or 50 minutes past the hour for WWVH, the time station located in Hawaii) you’ll hear a special announcement. There was also talk of an open house at the National Institute of Standards and Technology complete with a WWV birthday cake, but that has since been limited to 100 attendees who pre-registered.

For the machinists and wannabes out there, the Internet’s machine shop channels all pitched in this week on something called #tipblitz19, where everyone with a lathe or mill posted a short video of their favorite shop tip. There’s a ton of great tip out there now, with the likes of This Old Tony, Abom79, Stefan Gotteswinter, and even our own Quinn Dunki contributing timesaving – and finger saving – tips. Don’t stop there though – there’s a playlist with 77 videos at last count, many of them by smaller channels that should be getting more love. Check them out and then start making chips.

Most of us know that DLP chips, which lie behind the lens of the projectors that lull us to sleep in conference rooms with their white noise and warm exhaust, are a series of tiny mirrors that wiggle around to project images. But have you ever seen them work? Now you can: Huygens Optics has posted a fascinating video deep-dive into the workings of digital light processors. With a stroboscopic camera and a lot of fussy work, the video reveals the microscopic movements of these mirrors and how that syncs up with the rotation of a color filter wheel. It’s really fascinating stuff, and hats off to Huygens for pulling off the setup needed to capture this.

And speaking of tiny optics, get a load of these minuscule digital cameras, aptly described by tipster David Gustafik as “disturbingly small.” We know we shouldn’t be amazed by things like this anymore, but c’mon – they’re ridiculously tiny! According to the datasheet, the smaller one will occupy 1 mm² on a PCB; the larger stereo camera requires 2.2 mm². Dubbed NanEye, the diminutive cameras are aimed at the medical market – think endoscopy – and at wearables manufacturers. These would be a lot of fun to play with – just don’t drop one.

Getting The Heat On With A Thermal Camera

Need a quick way to tell your temperature before work tomorrow? Student maker [The Marpe] recently fashioned a sleek home-use thermal camera that even looks like a point and shoot. It works as an Android hardware add-on by integrating the readings from a MLX90640 far-infrared (FIR) thermal sensor with a STM32F042F6Px microcontroller. All this connects to an Android application via USB (MicroUSB or Type C).

On the app, users are able to view, take photos, and display the resulting thermal images from the open thermal camera. The code for the open Android application is also available on his GitHub.

The FIR sensors contain a small array of IR pixels, integrated to measure the ambient temperature of the internal chip, and supply sensor to measure the VDD. Each pixel on the sensor array responds to the IR energy focused on it to produce an electronic signal, which is processed by the camera processor to create a map of the apparent temperature of the object. The outputs of the sensors and VDD are stored in an internal RAM and are accessible through 3.3V I2C. They’re not only low-cost and fairly high resolution, but also available by order on Digi-Key.

The microcontroller is based on the STM32 platform, with 32-bit performance, low-power operation (at 2V to 3.6V and 48 MHz) and is fairly low-cost. The custom-designed PCBs are fitted inside a 3D-printed casing with M2.5 inserts to ease assembly. [The Marpe] used an Esra soldering iron to create a heat insert tool for easier assembly and more consistent results with the heat inserts, which made for a nicer overall finish.

The project has since been presented at the Ljublana Mini Maker Faire in Slovenia and the Trieste Mini Maker Faire in Italy. Here, the open thermal camera is being tested out on a faulty PCB with a shorted component, showing the location of the short on the Android application’s thermal camera display.

Other uses for the camera could be home insulation inspection, water leakage detection, wildlife observation, or even figuring out if your soldering iron is hot enough to use. We’ll say it’s a pretty useful DIY project!

Watch Legged Robot Run Circles Around Its Bigger Brethren

[Ben Katz] posted about bringing the Mini Cheetah (center, above) robot to the 2019 International Conference on Robotics and Automation (ICRA) held in Montréal, where it shared the floor with others for a workshop focusing on real-world deployment of legged robots. Those of you who haven’t been keeping up with legged robots may find yourselves delightfully surprised at the agility and fluid movements of this robot. Mini Cheetah may lack the effectors or sensors of the bigger units, but its nimbleness is undeniable.

[Ben] shared some footage of the robots together, and at about 7:22 in this video Mini Cheetah can be seen showing off a bit of flexing, followed by running around a larger unit. Another, shorter video is embedded below where you can see all the attendees moving about in a rare opportunity see them all together. You can even see the tiny one-legged hopping robot Salto if you watch closely!

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