3D Print Smoothing, With Lasers

As anyone who has used an FDM printer can tell you, it’s certainly not the magical replicator it’s often made out to be. The limitations of the platform are numerous — ranging from anisotropic material characteristics to visual imperfections in the parts. In an attempt to reduce the visual artifacts in 3D prints, [TenTech] affixed a small diode laser on a 3D printer.

Getting the 1.5 watt diode laser onto the printer was a simple matter of a bracket and attaching it to the control board as a fan. Tuning the actual application of the laser proved a little more challenging. While the layer lines did get smoothed, it also discolored the pink filament making the results somewhat unusable. Darker colored filaments seem to not have this issue and a dark blue is used for the rest of the video.

A half smoothed half unprocessed test printThe smoothing process begins at the end of a 3D print and uses non-planar printer movements to keep the laser at an ideal focusing distance. The results proved rather effective, giving a noticeably smoother and shiner quality than an unprocessed print. The smoothing works incredibly well on fine geometry which would be difficult or impossible to smooth out via traditional mechanical means. Some detail was lost with sharp corners getting rounded, but not nearly as much as [TenTech] feared.

For a final test, [TenTech] made two candle molds, one smoothed and one processed. The quality difference between the two resulting candles was minimal, with the smoothed one being perhaps even a little worse. However, a large amount of wax leaked into the 3D print infill in the unprocessed mold, with the processed mold showing no signs of leaking.

If you are looking for a bit safer of a 3D print post-processing technique, make sure to check out [Donal Papp]’s UV resin smoothing experiments!

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YouTube… Over Dial Up

In the days of yore, computers would scream strange sounds as they spoke with each other over phone lines. Of course, this is dial up, the predecessor to modern internet technology, offering laughable speeds compared to modern connections. But what if dial up had more to offer? Perhaps it could even stream a YouTube video. That’s what the folks over at The Serial Port set out to find out.

The key to YouTube over dial up is a little known part of the protocol added right around the time broadband was taking off called multilink PPP. This protocol allows for multiple modems connected to a PC in parallel for faster connections. With no theoretical limit in sight, and YouTube’s lowest quality requiring a mere 175 Kbps, the goal was clear: find if there is a limit to multilink PPP and watch YouTube over dialup in the process.

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Building A (Not Very) Portable Xbox

Modern handheld game consoles are impressive feats of engineering, featuring full fledged computers in near pocket-sized packages. So what happens if you take an original Xbox and sprinkle on some modern electronics and create a handheld? Well, if you’re [James] of James Channel, you end up with this sandwich of PCBs held together with hot glue and duck tape. 

The first order of miniaturization in this Xbox was replacing the hard drive. Because a CompactFlash card uses parallel ATA, that could be a simple drop in replacement. However, the Xbox locks the hard drive to the system requiring a mod chip for the CF card to work. Fortunately, the sacrificial Xbox came with a mod chip installed. After using an arcade machine to flash the card and copy over the contents of the drive, the CF card install was a breeze. 

For the screen and batteries, a portable DVD player that had remained unused since 2006 was repurposed. The battery cells were rather unhappy, but managed to get resurrected with some careful charging. As it turns out, the iPod 30 pin connector inside the portable screen contains an S-Video line. By tapping into that and adding in some power management for the batteries, the Xbox became a pile of PCBs that could maybe be taken places.

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Getting The Most Out Of ISM Transceivers Using Math

WiFi is an excellent protocol, but it certainly has its weaknesses. Its range in even a normal home is relatively limited, so you could imagine the sort of performance you’d expect through the hundred meters of dense woodland that [DO3RB] is trying to penetrate. So naturally the solution was to develop a new wireless transceiver for the ISM band. 

Of course, getting reliable packet transmission is tough. In a building with brick walls, WiFi will get around five to ten percent packet loss. For TCP to remain reliable, one percent packet loss is the maximum designed loss of this wireless protocol. In reality, the transceiver achieves 0.075% packet loss real world.

The crux of the magic behind this excellent reliability is the extended binary Golay code. By halving the bitrate, the Golay code is able to correct for up to four errors per codeword. While a more complicated scheme could have been used, the Golay code allowed for easy porting to an MCU thus simplifying the project. All this is encoded with frequency shift keying in the ISM band.

This magic is tied up inside an tiny SAMD21 paired with a RFM12BP wireless front end. Using TinyUSB, the interface shows up to the host as a USB Ethernet adapter making for seamless networking setups. With reliable bi-directional communication, you could theoretically use this as a home networking solution. However, this is realistically best for IoT devices as the speeds are around 56 kbit/s.

While this is an incredibly simple system, harking back to 90s networking, it certainly gets the job done in a neat and tidy manner. And if you too wish hark back to 90s radio communications, make sure to check out this satellite imagery hack next! 

Thanks [Bernerd] for the tip!

Making A Laptop With A Mechanical Keyboard

A laptop is one of the greatest tools at the disposal of a hacker. They come in all manner of shapes and sizes with all manner of features. But perhaps the greatest limit held by all laptops is their chiclet keyboard. While certainly serviceable, a proper mechanical keyboard will always reign supreme, which is why [flurples] built a laptop around a mechanical keyboard. 

Such a keyboard could not fit inside any normal laptop, so a custom machined case was in order. The starting point was a standard Framework Laptop 13. Its open source documentation certainly helped the project, but numerous parts such as the audio board and fingerprint sensor are not documented making for a long and tedious process. But the resulting machined aluminum case looks at least as good as a stock Framework chassis, all be it, quite a bit thicker.

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How Strong Of A Redbull Can You Make?

Energy drinks are a staple of those who want to get awake and energetic in a hurry. But what if said energy is not in enough of a hurry for your taste? After coming across a thrice concentrated energy drink, [Nile Blue] decided to make a 100 times concentrated Redbull.

Energy drinks largely consist of water with caffeine, flavoring and sugar dissolved inside. Because a solution can only be so strong, so instead of normal Redbull, a sugar free variant was used. All 100 cans were gathered into a bucket to dry the mixture, but first, it had to be de-carbonated. By attaching a water agitator to a drill, all the carbon dioxide diffused in the water fell out of solution. A little was lost, but the process worked extremely well.

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A Look At Not An Android Emulator

Recently, Linux has been rising in desktop popularity in no small part to the work on WINE and Proton. But for some, the year of the Linux desktop is not enough, and the goal is now for the year of the Linux phone. To that end, an Android Linux translation layer called Android Translation Layer (we never said developers were good at naming) has emerged for those running Linux on their phones.

Android Translation Layer (ATL) is still in very early days, and likely as not, remains unpackaged on your distro of choice. Fortunately, a workaround is running an Alpine Linux container with graphics pass through via a tool like Distrobox or Toolbox. Because of the Alpine derived mobile distribution postmarketOS, ATL is packaged in the Alpine repos.

In many ways, running Android apps on Linux is much easier then Windows apps. Because Android apps are architecture independent, hardware emulation is unnecessary. With such similar kernels, on paper at least, Android software should run with minimal effort on Linux. Most of what ATL provides is a Linux/Android hardware abstraction layer glue to ensure Android system calls make their way to the Linux kernel.

Of course, there is a lot more to running Android apps, and the team is working to implement the countless Android system APIs in ATL. For now, older Android apps such as Angry Birds have the best support. Much like WINE, ATL will likely devolve into a game of wack-a-mole where developers implement fresh translation code as new APIs emerge and app updates break. Still, WINE is a wildly successful project, and we hope to see ATL grow likewise!

If you want to get your Android phone to talk to Linux, make sure to check out this hack next!