Product Review: The TinySA, A Shirt-Pocket Sized Spectrum Analyzer

November 9, 2020 by Dan Maloney 39 Comments

I suppose most of us have had the experience of going to the mailbox and seeing that telltale package in the white plastic bag, the sign that something has just arrived from China. This happened to me the other day, and like many of you it was one of those times when I puzzled to myself: “I wonder what I bought this time?”

With so many weeks or months between the time of your impulsive click on the “Buy Now” button on AliExpress or eBay and the slow boat from China actually getting the package to your door, it’s easy enough to forget what exactly each package contains. And with the price of goods so low, the tendency to click and forget is all the easier. That’s not necessarily a good thing, but I like surprises as much as the next person, so I was happy to learn that I was now the owner of a tinySA spectrum analyzer. Time for a look at what this little thing can do.

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New Raspberry Pi 400 Is A Computer In A Keyboard For $70

November 2, 2020 by Elliot Williams 248 Comments

The newest Raspberry Pi 400 almost-all-in-one computer is very, very slick. Fitting in the size of a small portable keyboard, it’s got a Pi 4 processor of the 20% speedier 1.8 GHz variety, 4 GB of RAM, wireless, Ethernet, dual HDMI outputs, and even a 40-pin Raspberry Standard IDE-cable style header on the back. For $70 retail, it’s basically a steal, if it’s the kind of thing you’re looking for because it has $55 dollars worth of Raspberry Pi 4 inside.

In some sense, it’s getting dangerously close to fulfilling the Raspberry Pi Dream. (And it’s got one more trick up it’s sleeve in the form of a huge chunk of aluminum heat-sinked to the CPU that makes us think “overclocking”.)

We remember the founding dream of the Raspberry Pi as if it were just about a decade ago: to build a computer cheap enough that it would be within everyone’s reach, so that every school kid could have one, bringing us into a world of global computer literacy. That’s a damn big goal, and while they succeeded on the first count early on, putting together a $35 single-board computer, the gigantic second part of that master plan is still a work in progress. As ubiquitous as the Raspberry Pi is in our circles, it’s still got a ways to go with the general population.

The Raspberry Pi Model B wasn’t, and isn’t, exactly something that you’d show to my father-in-law without him asking incredulously “That’s a computer?!”. It was a green PCB, and you had to rig up your own beefy 5 V power supply, figure out some kind of enclosure, scrounge up a keyboard and mouse, add in a monitor, and only then did you have a computer. We’ve asked the question a couple of times, can the newest Raspberry Pi 4B be used as a daily-driver desktop, and answered that in the affirmative, certainly in terms of it having adequate performance.

But powerful doesn’t necessarily mean accessible. If you want to build your own cyberdeck, put together an arcade box, screw a computer into the underside of your workbench, or stack together Pi Hats and mount the whole thing on your autonomous vehicle testbed, the Raspberry Pi is just the ticket. But that’s the computer for the Hackaday crowd, not the computer for everybody. It’s just a little bit too involved.

The Raspberry Pi 400, in contrast, is a sleek piece of design. Sure, you still need a power supply, monitor, and mouse, but it’s a lot more of a stand-alone computer than the Pi Model B. It’s made of high-quality plastic, with a decent keyboard. It’s small, it’s light, and frankly, it’s sexy. It’s the kind of thing that would pass the father-in-law test, and we’d suggest that might go a long way toward actually realizing the dream of cheaply available universal (open source) computing. In some sense, it’s the least Hackaday Raspberry Pi. But that’s not saying that you might not want one to slip into your toolbag.

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Inputs Of Interest: The OrbiTouch Keyless Keyboard And Mouse

October 12, 2020 by Kristina Panos 19 Comments

I can’t remember how exactly I came across the OrbiTouch keyboard, but it’s been on my list to clack about for a long time. Launched in 2003, the OrbiTouch is a keyboard and mouse in one. It’s designed for people who can’t keyboard regularly, or simply want a different kind of experience.

The OrbiTouch was conceived of by a PhD student who started to experience carpal tunnel while writing papers. He spent fifteen years developing the OrbiTouch and found that it could assist many people who have various upper body deficiencies. So, how does it work?

It’s Like Playing Air Hockey with Both Hands

To use this keyboard, you put both hands on the sliders and move them around. They are identical eight-way joysticks or D-pads, essentially. The grips sort of resemble a mouse and have what looks like a special resting place for your pinky.

One slider points to groups of letters, numbers, and special characters, and the other chooses a color from a special OrbiTouch rainbow. Pink includes things like parentheses and their cousins along with tilde, colon and semi-colon. Black is for the modifiers like Tab, Alt, Ctrl, Shift, and Backspace. These special characters and modifiers aren’t shown on the hieroglyphs slider, you just have to keep the guide handy until you memorize the placement of everything around the circle.

You’re gonna need a decent amount of desk space for this. Image via OrbiTouch

The alphabet is divided up into groups of five letters which are color-coded in rainbow order that starts with orange, because red is reserved for the F keys. So for instance, A is orange, B is yellow, C is green, D is blue, E is purple, then it starts back over with F at orange. If you wanted to type cab, for instance, you would start by moving the hieroglyph slider to the first alphabet group and the color slider to green.

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That Elusive Valve Amp Sound, For Not A Lot! (There Has To Be A Catch)

September 1, 2020 by Jenny List 54 Comments

It was with considerable interest last month that I set out to track down where in the world there are still factories making tubes. My research found them in Slovakia, Russia, and China, and it’s fairly certain I didn’t find all the manufacturers by any means. There appeared to be a whole class of mundane tubes still in production that weren’t to be found on their glossy websites. A glance at any outlet through which Chinese modules can be bought will find this type of tube in small audio amplifier projects, and some of them can be astoundingly cheap. When faced with cheap electronics of course I’m tempted to buy some, so I parted with about £10 ($12.50) and bought myself a kit for a two-tube device described as a stereo preamplifier and headphone amplifier.

An Unusual Tube Choice For Audio

What I received for my tenner was a press-seal bag with a PCB and a pile of components, and not much else. No instructions, which would have been worrisome were the board not clearly marked with the value of each component. The circuit was on the vendor’s website and is so commonly used for these sort of kits that it can be found all over the web — a very conventional twin common-cathode amplifier using a pair of 6J1 miniature pentodes, and powered through a +25 V and -25 V supply derived from a 12 VAC input via a voltage multiplier and regulator circuit. It has a volume potentiometer, two sets of phono sockets for input and output, and the slightly naff addition of a blue LED beneath each tube socket to impart a blue glow. I think I’ll pass on that component.

The 6J1 seems to be ubiquitous throughout the Chinese kits, which is surprising when you understand that it’s not an audio tube at all. Instead it’s a small-signal VHF amplifier, a rough equivalent of the European EF95, and would be much more at home in an FM radio receiver or turret TV tuner from the 1950s. I can only assume that somewhere in China there’s a tube factory tooled up for radio tube production that is targeting this market, because another tube you will see in audio power amplifier kits is the FU32 or QQV03-20 in European parlance, a large power beam tetrode that might have been found in a 1950s military radio transmitter. Still just as if you were to use an RF transistor in an audio circuit it would give good account of itself, so it is with an RF tube. There is no reason a 6J1 won’t do an acceptable job in a circuit such as this one.

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Hands-On: Wireless Login With The New Mooltipass Mini BLE Secure Password Keeper

July 23, 2020 by Maya Posch 34 Comments

Remembering passwords is one of those things which one just cannot seem to escape. At the very least, we all need to remember a single password: namely the one for unlocking a password manager. These password managers come in a wide variety of forms and shapes, from software programs to little devices which one carries with them. The Mooltipass Mini BLE falls into the latter category: it is small enough to comfortably fit in a hand or pocket, yet capable of remembering all of your passwords.

Heading into its crowdfunding campaign, the Mooltipass Mini BLE is an evolution of the Mooltipass Mini device, which acts as a USB keyboard by default, entering log-in credentials for you. With the required browser extension installed, this process can also be automated when browsing to a known website. Any new credentials can also be saved automatically this way.

Where the Mooltipass Mini BLE differs from the original is in that it also adds a Bluetooth (BLE) mode, enabling it to be used easily with any BLE-capable device, including laptops and smartphones, without having to dig around for a USB cable and/or OTG adapter.

I have already been using the original Mooltipass Mini for a while, and the Mooltipass team was kind enough to send me a prototype Mooltipass Mini BLE for evaluation and comparison. Let’s take a look.

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Review: Calculator Kit Is Just A Few Hacks From Greatness

July 2, 2020 by Tom Nardi 48 Comments

While most people are satisfied with a calculator application on their smartphone these days, there’s still something to be said for the old fashioned desk calculator. Maybe it’s the fact the batteries last long enough that you can’t remember the last time you changed them, or the feel of physical buttons under your fingers. It could even be the fact that it keeps your expensive smartphone from needing to sit out on the workbench. Whatever the reason, it’s not uncommon to see a real-life calculator (or two) wherever solder smoke tends to congregate.

Which is precisely the idea behind this DIY calculator kit. Available from the usual overseas retailers for about $15 USD, it has some hobbyist-oriented features such as the ability to decode resistor color bands, convert hexadecimal numbers, and calculate resistor values for driving LEDs. If you’re going to keep a knock-around calculator on your bench, why not build the thing yourself?

Given the dual nature of this product, a DIY electronics kit and a functional desk calculator for electronic hobbyists, it seems only appropriate to review both aspects of it individually. Which is good, since there may be more to this product than just the sum of its parts.

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Books You Should Read: The Boy Who Harnessed The Wind

May 14, 2020 by Steven Dufresne 30 Comments

For many of us, our passion for electronics and science originated with curiosity about some device, a computer, radio, or even a car. The subject of this book has just such an origin. However, how many of us made this discovery and pursued this path during times of hunger or outright famine?

That’s the remarkable story of William Kamkwamba that’s told in the book, The Boy Who Harnessed the Wind. Remarkable because it culminates with his building a windmill (more correctly called a wind turbine) that powered lights in his family’s house all by the young age of fifteen. As you’ll see, it’s also the story of an unyielding thirst for knowledge in the face of famine and doubt by others.

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