Reproduced And Recovered: The First Chinese Keyboard-based MingKwai Typewriter

We all know what a typewriter looks like, and how this has been translated directly into the modern day computer keyboard, or at least many of us think we do. Many cultures do not use a writing system like the Roman or Cyrillic-style alphabets, with the Chinese writing system probably posing the biggest challenge. During the rise of mechanical typewriters, Chinese versions looked massive, clumsy and slow as they had to manage so many different symbols. All of them, except for one prototype of the MingKwai, which a group of Chinese enthusiasts have recently built themselves using the patent drawings.

Interestingly, when they started their build, it was thought that every single prototype of the MingKwai had been lost to time. That was before a genuine prototype was found in a basement in New York and acquired by Stanford University Libraries, creating the unique experience of being able to compare both a genuine prototype and a functional recreation.

Considered to be the first Chinese typewriter with a keyboard, the MingKwai (明快打字機, for ‘clear and fast’) was developed by [Lin Yutang] in the 1940s. Rather than the simple mechanism of Western typewriters where one key is linked directly to one hammer, the MingKwai instead uses the keys as a retrieval, or indexing mechanism.

Different rows select a different radical from one of the multiple rolls inside the machine, with a preview of multiple potential characters that these can combine to. After looking at these previews in the ‘magic eye’ glass, you select the number of the target symbol. In the video by the Chinese team this can be seen in action.

Although [Lin]’s MingKwai typewriter did not reach commercialization, it offered the first glimpse of a viable Chinese input method prior to computer technology. These days the popular pinyin uses the romanized writing form, which makes it somewhat similar to the standard Japanese input method using its phonetic kana system of characters. Without such options and within the confined system of 1940s electromechanical systems, however, the MingKwai is both an absolute marvel of ingenuity, and absolutely mindboggling even by 2020s standards.

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Regular Old Diodes Can Be More Photosensitive Than You Think

[Dhananjay Gadre] happened across a useful little trick the other day. Take any old 1N4148 or 1N914 glass-package signal diode and wire it up right, and you’ve got yourself a nifty little IR detector.

It’s that simple.

The trick is to treat the diode just like you would a proper IR photodiode. The part should be reverse biased with a resistor inline, and the signal taken from the anode side. Point an IR remote at your little diode and you’ll readily see the modulated signal pop up on a scope, clear as day.

The phenomenon is discussed at length over on Stack Exchange. Indeed, it’s a simple fact that most semiconductor devices are subject to some sort of photoelectric effect or another. It’s just that we stick the majority of them in opaque black packages so it never comes up in practice. In reality, things like photodiodes and phototransistors aren’t especially different from the regular parts—they’re just put in transparent packages and engineered and calibrated to give predictable responses when used in such a way.

Is this the way you’d go if your project needed an IR detector? Probably not—you’d be better served buying the specific parts you need from the outset. But, if you find yourself in a pinch, and you really need to detect some IR signals and all you’ve got on hand is glass-package signal diodes? Yeah, you can probably get it to work.

While this trick is well known to many oldheads, it’s often a lightbulb moment for many up-and-coming engineers and makers to realize this. Glass-packaged diodes aren’t the only light-sensitive parts out there, either. As we’ve explored previously, certain revisions of Raspberry Pi would reboot if exposed to a camera flash, while you can even use regular old LEDs as sensors if you’re so inclined. If you’ve got your own secret knowledge about how to repurpose regular components in weird ways, don’t hesitate to notify the tipsline!

Print in place board holder

Print-and-Clamp: Rubber Band PCB Stand Slides Into Duty

When it comes to soldering on a PCB it almost always helps to have some way to hold the board off your workbench, allowing leads to pass though with out making it unstable and keeping it level while working with tiny components. This project sent in by [Mel] was born out of necessity he was going to be teaching a soldering class and needed a way to keep boards in place, and so designed this Print-in-place PCB holder.

While there are certainly a long list of products designed to serve this function [Mel] took advantage of some idle 3D printers to turn out PCB stands that require no assembly, just the addition of a rubber band and they are ready for use. Part of the challenge of print in place 3D prints is dialing in the tolerances of your design and printer, and for this [Mel] printed some smaller slider mechanisms that were quick to print and iterate with until he was happy and could start turning out the larger design using those values.

The full PCB holder includes 3 independent sliders allowing for boards of all shapes and sizes to be held. To tension the board mounts there is a slow lower down on the uprights to allow for a rubber band to be added pulling all three towards the center. Finally [Mel] included small trays between the 3 sliders to give you a convenient place to components are you assemble your board. The 3D print falls are all available for download and [Mel] also included the small slider as a 3D print for you to check your printer tollerances before you run off the final design. Thanks [Mel] for sending in your soldering tool design, it’s a great addition to some of our other soldering assistant devices we’ve featured.

Dual-Arm Mobile Bot Built On IKEA Cart Costs Hundreds, Not Thousands

There are many incredible open-source robotic arm projects out there, but there’s a dearth of affordable, stable, and mobile robotic platforms with arms. That’s where XLeRobot comes in. It builds on the fantastic LeRobot framework to make a unit that can be trained for autonomous tasks via machine learning, as well as operated remotely.

XLeRobot, designed by [Vector Wang], has a pretty clever design that makes optimal use of easy to obtain parts. In addition to the mostly 3D-printed hardware, it uses an IKEA cart with stacked bin-like shelves as its main frame.

The top bin holds dual arms and a central stalk with a “head”. There’s still room left in that top bin, a handy feature that gives the robot a place to stow or carry objects.

The bottom of the cart gets the three-wheeled motion unit. Three omnidirectional wheels provide a stable base while also allowing the robot to propel itself in any direction and turn on a dime. The motion unit bolts to the bottom, but because the IKEA cart’s shelf bottoms are a metal mesh, no drilling is required.

It’s all very tidy, and results in a mobile robotics platform that is cheap enough for most hobbyists to afford, while being big enough to navigate indoor environments and do useful tasks.

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MCE Blaster Translates TTL For Modern(ish) Monitors

VGA isn’t much used anymore, but it’s not hard to get a hold of monitors with that input. How about the older standards like EGA, CGA, or MDA? Well, it’s good luck on eBay or at the recycling yard to get a period-appropriate monitor, but the bulky, fragile CRTs seem to have been less likely to survive than computers that drove them. That’s what [Scrap Computer]’s MCE Blaster is for: it sits betwixt the retrocomputer’s TTL output and the VGA input of a (more) modern monitor, be it CRT or LCD.

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Folding Lamp Becomes A Tasty Reverb Tank

If you’re a musician and you want a reverb effect, there are lots of ways to go about it. You can use software plugins, all kinds of rack-mount effects, or pedals. Or, as [David] has done, you could go with a lamp.

[David’s] build is straightforward enough in concept—he just chose a relatively unconventional item to use as a reverb tank. The lamp might seem like an odd choice, but it actually does a decent job at resonating because of its metal construction and the multiple springs that tension the structure. [David] turns the lamp into a reverb by fitting it with a Vidsonix Ghost audio transducer to put sound into the structure—picture the magnetic driver of a loudspeaker without the cone fitted, and you get the idea. Piezo elements were then used as contact mics to pick up reverberations from the lamp itself. Everything was assembled with a bunch of lab stands that give the build a rather nice aesthetic. The reverb time isn’t particularly long, but the sound is hauntingly beautiful.

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Repurposing Dodgy Android TV Boxes As Linux Boxes

Marketplaces and e-waste recycling centers are practically overflowing with the things: ARM-based streaming TV boxes that run some — usually very outdated and compromised — version of Android. While you can use them for their promised streaming purposes, they’re invariably poorly optimized and often lie about their true hardware specifications. Which leaves the most important question: can you install Linux on these SBCs and use them as a poor man’s Raspberry Pi alternative? The answer, according to [Oleksii’s Tech] on YouTube is ‘sorta’.

The fake H313 TV box SBC in all its glory. (Credit: Oleksii's Tech, YouTube)
The fake H313 TV box SBC in all its glory. (Credit: Oleksii’s Tech, YouTube)

The commonly seen X96Q clone Android TV box that [Oleksii] bought for $10 is a good example. The clone advertises itself as based on a quad-core Cortex-A53 AllWinner H313 SoC, like the genuine X96Q, but actually has a Rockchip RK3229 inside with correspondingly far lower performance. After you have determined what the actual hardware inside the box is, you can get a copy of Armbian for that particular SoC. Here, the Rk322x-box minimal image was used, with the box booting straight off an SD card. Some Android TV boxes require much more complicated methods to even boot off external media, so this was a lucky break.

Continuing the hardware scam, it was advertised as having 2 GB of RAM and 16 GB of Flash, but it actually has just 1 GB of RAM and 8 GB of eMMC Flash. This was enough to get Armbian desktop up and running, but that’s about all you can do. Desktop application performance was atrocious, mostly due to the CPU’s quad Cortex-A7 cores struggling to keep up.

As also suggested in the comments, the best use for these low-spec SBCs is probably to run light server applications on them, including Pi-Hole, Samba, an IRC bouncer, and so on. They’re pretty low-power, often have the requisite Ethernet built in, and it keeps another bit of potential e-waste from getting scrapped.

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