[Ashhar Farhan]’s Done It Again!

March 14, 2017 by 15 Comments

If you are a regular follower of these pages as well as a radio amateur, you may well have heard of [Ashhar Farhan, VU2ESE]. He is the designer of the BitX, a simple single-sideband transceiver that could be built for a very small outlay taking many of its components from a well-stocked junk box.

In the years since the BitX’s debut there have been many enhancements and refinements to the original, and it has become something of a standard. But it’s always been a single-band rig, never competing with expensive commercial boxes that cover the whole of the available allocations.

With his latest design, he’s changed all that. The uBITX (Micro-BITX when spoken aloud), is an SSB and CW transceiver that covers all of the HF amateur bands, and like the original is designed for the home constructor on a budget. It shows its heritage in the use of bi-directional amplifiers, but diverges from the original with a 45 MHz first IF and an Arduino/SI5351 clock generator in the place of a VFO. It looks to be an excellent design in the spirit of the original, and we can’t wait to see them in the wild.

He’s put up a YouTube video which we’ve placed below the break. His write-up is extensive and fascinating, but it is his closing remarks which sum up the project and the reason why you should build one. We don’t often reproduce entire blocks of text, but this one says it so well:

As a fresh radio amateur in the 80s, one looked at the complex multiband radios of the day with awe. I remember seeing the Atlas 210x, the Icom 720 and Signal One radios in various friends’ shacks. It was entirely out of one’s realm to imagine building such a general coverage transceiver in the home lab.

Devices are now available readily across the globe through online stores, manufacturers are more forthcoming with their data. Most importantly, online communities like the EMRFD’s Yahoo group, the BITX20’s groups.io community etc have placed the tribal knowledge within the grasp of far flung builders like I am.

One knows that it was just a matter of breaking down everything into amplifiers, filters, mixers and oscillators, but that is just theory. The practice of bringing a radio to life is a perpetual ambition. The first signal that the sputters through ether, past your mess of wires into your ears and the first signal that leaps out into the space from your hand is stuff of subliminal beauty that is the rare preserve of the homebrewer alone.

At a recent eyeball meet, our friend [Dev(VU2DEV)] the famous homebrewer said “Now is the best time to be a homebrewer”. I couldn’t disagree.

If you build a uBITX, please share it with us!

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Hands-On Nvidia Jetson TX2: Fast Processing For Embedded Devices

March 14, 2017 by 74 Comments

The review embargo is finally over and we can share what we found in the Nvidia Jetson TX2. It’s fast. It’s very fast. While the intended use for the TX2 may be a bit niche for someone building one-off prototypes, there’s a lot of promise here for some very interesting applications.

Last week, Nvidia announced the Jetson TX2, a high-performance single board computer designed to be the brains of self-driving cars, selfie-snapping drones, Alexa-like bots for the privacy-minded, and other applications that require a lot of processing on a significant power budget.

This is the follow-up to the Nvidia Jetson TX1. Since the release of the TX1, Nvidia has made some great strides. Now we have Pascal GPUs, and there’s never been a better time to buy a graphics card. Deep learning is a hot topic that every new CS grad wants to get into, and that means racks filled with GPUs and CUDA cores. The Jetson TX1 and TX2 are Nvidia’s strike at embedded deep learning, or devices that need a lot of processing power without sucking batteries dry.

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The Altair Shield

March 14, 2017 by 24 Comments

From PDPs to Connection Machines, the Hackaday crowd are big fans of blinkenlights. While this project isn’t an old CPU, RAM, ROM, and an S-100 bus wrapped up in a fancy enclosure, it is a great recreation of the Altair 8800, the historic kit computer that supposedly launched the microcomputer revolution.

[Justin] says his project is just another Altair 8800 clone, but this one is cut down to the size of an Arduino shield. This is in stark contrast to other Altair recreations, whether they are modern PCs stuffed in an old case, modern replicas, or a board that has the same functionality using chunky toggle switches.

On board [Justin]’s pocket-sized Altair are a few LEDs, some DIP switches, and an octet of spring-loaded dual throw switches that wouldn’t look out of place in a 40-year old computer.

This shield targets the Arduino Due rather than the Mega, but only because the Due performs better running an Altair simulation. Everything is there, and a serial terminal is available ready to run BASIC or any other ancient OS.

Zero-Intrusion Wireless Light Switch

March 14, 2017 by 51 Comments

What do you do if your light switch is too far from your desk, and you’re in a rental property so you can’t put in extra wiring to install an electronic control for it? Get up and turn it on or off by hand? Of course not!

If you are [Guyfromhe], you solve this problem with a servo attached to a screw-on light switch faceplate, and you control it with a pair of Arduino/nRF24L01 combos. It’s a pretty simple arrangement, the wireless link simply takes the place of a serial cable that instructs the Arduino on the light switch to operate the servo that in turn moves the switch. The whole thing is triggered through his home automation system, which in turn responds to an Amazon Dash button on his desk. Yes, it’s complex. But turning on the light has been automated without intrusion into his landlord’s domain, and that’s all that matters.

On a more serious note, he’s put some Arduino code up on his write-up, as well as a YouTube video we’ve put below the break.

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Build Your Own Animated Turn Signals

March 13, 2017 by 79 Comments

Automotive lighting used to be strictly controlled, particularly in the United States — anyone remember sealed beam headlamps? These days, pretty much anything goes. You can even have an animated turn signal, because a simple flash isn’t fancy enough these days. You can get a scanning-LED turn signal on your new model Audi, among others. [Shravan] wanted this on their Mazda and set about building an animated turn signal and daytime running lights setup for their car.

It’s not a complicated build by any means; an off-the-shelf WS2812B strip provides the blinkums, an Arduino Nano the smarts. Using a modified library to drive the LEDs allowed [Shravan] to get things running with a minimum of fuss. We’d love to see a little more of the gritty reality of this build — how the Nano is getting directional signals from the car, and how it’s all wired up and bolted on. When you’re installing custom hardware onto a vehicle, the devil really is in the details. It’s supremely difficult to create something that looks tidy and functions well.

It’s amazing to think about how far we’ve come. When high-brightness LEDs first came on to the market in the 1990s, you would have been on the hook for wiring your own loom to connect the 20+ LEDs, building your own driver circuitry, and likely etching a custom PCB — all the while you programmed a PIC in assembly as it dangled off a parallel-port programmer. But then again, our cave-dwelling ancestors didn’t even have matches. Time marches on. Use today’s technology to build the very best things you can.

We love seeing car mods, particularly those that are well executed. Check out [Dave]’s interior lighting mods to the Nissan Juke — a car this writer has weighty opinions about. Video after the break.

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Robot Hand Goes Wireless

March 13, 2017 by 7 Comments

We can’t decide if [MertArduino’s] robotic hand project is more art or demonstration project. The construction using springs, fishing line, and servo motors isn’t going to give you a practical hand that could grip or manipulate anything significant. However, the project shows off a lot of interesting construction techniques and is a fun demonstration for using nRF24L01 wireless in a project. You can see a video of the contraption, below.

A glove uses homemade flex sensors to send wireless commands to the hand. Another Arduino drives an array of servo motors that make the fingers flex. You don’t get fine control, nor any real grip strength, but the hand more or less will duplicate your movements. We noticed one finger seemed poorly controlled, but we suspect that was one of the homemade flex sensors going rouge.

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Tea Making The Mechanical Way

March 13, 2017 by 34 Comments

For some of those who are aficionados of the drink, tea making can be serious business. For them, strong, black, leaf tea left for ages to stew in a stained teapot that would strip the hairs off your chest (like it should be made) just won’t do. These beverage anarchists demand a preparation process of careful temperature regulation and timing, and for some reason repeatedly dunking a teabag in the water.

For them, [Dorian Damon] has an automated solution to getting the crucial dunking process right. He’s made an automatic tea bag dunker. The teabag is mounted on a slide operated by a crank, and the crank is driven through a pair of bicycle hubs. Motive power comes from a mains shaded-pole motor, an unusual bi-directional one of which he only uses one side. He measured his personal dunking rate at about 50 per minute, so he only needed a 4:1 reduction to match the motor at 200 RPM.

The resulting machine will happily dunk his tea bag at that rate for as long as it’s left switched on. He’s put a few videos up, of which we’ve posted one below the break.

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