Author: Al Williams

4509 Articles

How’s That 2.5D Printer Working For You?

September 9, 2019 by 35 Comments

We’ve noticed a trend lately that advanced 3D printing people are calling their normal print setup as 2.5D, not 3D. The idea is that while the machine has 3 axes, the actual geometry generation is typically only in the X and Y axis. The Z axis simply lifts up to the next layer unless you are working in vase mode. [Teaching Tech] wanted to experiment with real 3D printing where the Z axis actually helps build the shape of the printed object, not just advancing with each step.

As it turns out his first investigation linked back to one of our early posts on the topic. There’s been more recent work though, and he found that too. It took a little surgery to get more Z clearance, but nothing too serious — just a movement of a fan.

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Cheap Stereo Microscope Helps With SMD

September 8, 2019 by 22 Comments

Soldering is best done under magnification. Parts become ever smaller and eyes get weaker, so even if you don’t need magnification now, you will. [Makzumi] didn’t want to shell out $400 or more for a good microscope so he hacked one from some cheap binoculars from the toy section on Amazon.

A lot of magnifiers aren’t really good for soldering because the distance between the work and the lens isn’t very large. The hacked ‘scope has about 4 inches of working distance, which is plenty of room to stick some solder and a hot iron under there. The resulting magnification is about 12 or 15X and he claims that the cell phone pictures he’s included aren’t as good as really looking through the eyepieces yourself.

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An RFID Ring For The Body Mod Squeamish

September 8, 2019 by 27 Comments

Some people get inked, while others get henna or those water transfer tattoos you might find in a box of Cracker Jack. [Becky] wanted the benefits of having an RFID tag in her finger — unlock doors or log into your computer with a swipe of your finger — but wasn’t ready to get an implant. Her solution: make an artistic ring that conceals a tiny glass capsule RFID tag.

Besides not having to shove some tech under your epidermis, there are a few other advantages: you can change out tags as easy as changing rings, for one. You can also easily loan your ring to someone just as you might give them keys to your door.

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Linux Fu: Interactive SSH Applications

September 6, 2019 by 4 Comments

[Drew DeVault] recently wrote up some interesting instructions on how to package up interactive text-based Linux commands for users to access via ssh. At first, this seems simple, but there are quite a few nuances to it and [Drew] does a good job of covering them.

One easy way — but not very versatile — is to create a user and make the program you want to run the default shell. The example used is to make /usr/bin/nethack the shell and now people can log in as that user and play nethack. Simple, right? However, there are better ways to get there.

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Ham Radio Company Wins Big

September 5, 2019 by 39 Comments

It is sort of the American dream: start a company in your garage and have it get crazy big. After all, Steve Jobs, Bill Gates, and even Bill Hewlett and Dave Packard did it. Seems hard to do these days, though. However, one ham radio company that has been pushing the edge of software defined radio appears to be well on the way to becoming more than its roots. FlexRadio has teamed with Raytheon to undertake a major project for the United States Air Force.

The Air Force has given Raytheon and FlexRadio $36 million to develop an HF radio based on the existing SmartSDR/Flex-6000. ARRL news reports quote FlexRadio’s CEO as saying that the investment in the military radios will pay dividends to the firm’s ham radio customers.

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TinyGo Brings Go To Arduino

September 4, 2019 by 25 Comments

Go — a modern programming language with roots at Google — is one of the new generation languages that would like to unseat C (and C++) for what we think of as traditional programming. It is only for PCs, though, right? Not so fast! TinyGo provides a compiler that — in their words — is for small places. How small? They can target code for the Arduino Uno or the BBC micro:bit. It can also produce code for x86 or ARM Linux (both 32- and 64-bit) as well as WebAssembly. They claim that a recent project to add ESP8266 and EPS32 support to LLVM will eventually enable TinyGo to target those platforms, too.

As you would expect, there are some subtle differences between TinyGo and the full-blown version. The compiler handles the entire program at once which is slower but offers more for optimization. Certain optimizations for interface methods are not used in TinyGo, and global variable handling changes to accommodate moving data from flash to RAM efficiently. TinyGo passes parameters in registers.

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RISC-V Uses Carbon Nanotubes

August 31, 2019 by 3 Comments

In a recent article in Nature, you can find the details of a RISC-V CPU built using carbon nanotubes. Of course, Nature is a pricey proposition, but you can probably find the paper by its DOI number if you bother to look for it. The researchers point out that silicon transistors are rapidly reaching a point of diminishing returns. However, Carbon Nanotube Field Effect Transistors (CNFETs) overcome many of these disadvantages.

The disadvantage is that the fabrication of CNFETs has been somewhat elusive. The tubes tend to clump and yields are low. The paper describes a method that allowed the fabrication of a CPU with over 14,000 transistors. A wafer gets nanotubes grown all over it and then some of them are removed. In addition, some design rules mitigate other problems.

In particular, a small percentage of the CNFETs will become metallic and have little to no bandgap. However, the DREAM design rules can increase the tolerance of the design to metallic CNFETs with no process changes.

Before you get too excited, limitations in channel length and contact size keep the processor running at a blazing 10 kHz. To paraphrase Weird Al, your operating system boots in a day and a half. The density isn’t great either since working around stray and metallic CNFETs means each transistor has multiple nanotubes in use.

On the other hand, it works. New technology doesn’t always match old technology at first, but you have to crawl before you walk, and walk before you run.

We imagine you won’t be able to buy this for $8 any time soon even if you wanted to. At 10 kHz, it probably isn’t going to make much of a desktop PC anyway.