Radio Amateuring Like It’s 1975

December 7, 2017 by 33 Comments

It was a tweet from an online friend in the world of amateur radio, featuring a transmitter design published in Sprat, the journal of the G-QRP club for British enthusiasts of low-power radio. The transmitter was very simple, but seriously flawed: keying the power supply line would cause it to exhibit key clicks and frequency instability. It would probably have been far better leaving the oscillator connected full-time and keying the supply to the amplifier, with of course a suitable key click filter.

[M0CVO]'s Tweet that started it all
[M0CVO]’s Tweet that started it all
We’ve all probably made projects that get the job done at the expense of a bit of performance and economy, and from one angle this circuit is a fantastic example of that art. But it’s not the shortcomings of direct PSU keying a small transmitter that has brought it here, but observation instead of what it represents. Perhaps my social group of radio amateurs differs from the masses, but among them the universal lament is that there is nothing new in a simple transistor transmitter that could just as well have been published in 1977 as 2017.

To explain why this represents a problem, it’s worth giving some background. Any radio amateur will tell you that amateur radio is a wonderful and diverse pastime, in fact a multitude of pastimes rolled into one. Working DX? Got you covered. Contesting? UR 599 OM QRZ? Digital modes pushing the envelope of atmospheric propagation? Satellites? SDRs? GHz radio engineering? All these and many more can be yours for a modest fee and an examination pass. There was a time when radio was electronics, to all intents and purposes, and radio amateurs were at the vanguard of technology. And though electronics has moved on from those days of purely analogue communications and now stretches far beyond anything you’d need a licence and a callsign to investigate for yourself, there are still plenty of places in which an amateur can place themselves at the cutting edge. Software defined radio, for instance, or digital data transmission modes. With an inexpensive single board computer and a few components it is now possible to create a software-defined digital radio station with an extremely low power output, that can be copied on the other side of the world. That’s progress, it’s not so long ago that you would have required a lot of dollars and a lot of watts to do that. Continue reading “Radio Amateuring Like It’s 1975” →

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Hackaday Links: December 3, 2017

December 3, 2017 by 29 Comments

Remember the Psion? Back when PDAs were a thing, the Psion was the best you could get. It was, effectively, a palm-top computer with a real qwerty keyboard. It didn’t have Bluetooth, it couldn’t browse the web, and it didn’t have WiFi, but this was an AA-powered productivity machine that could fit in your pocket. Now there’s a new palmtop from Psion engineers. The Gemini PDA is basically a smartphone with a real keyboard that runs Ubuntu. It’s also has a smaller battery than other devices with this form factor, meaning the TSA thinks it’s a smartphone. This thing is going to be cool.

TechShop, Inc. has reached an agreement to sell the company to TechShop 2.0, LLC. New ownership seeks to re-open, continue running makerspaces. Details coming soon.

Arcade monitors are cool, and vector monitors are even cooler. [Arcade Jason] created a gigantic 36″ vector monitor. It’s thirty-six inches of Gravitar, in all its vector glory.

A few links posts ago, I pointed out someone was selling really awesome, really cheap LED panels on eBay. I got my ten panels, and [Ian Hanschen] bought sixty or some other absurd amount. Now, these panels are going for $300 for a 10-pack instead of $50. Sorry about that. Nevertheless, the reverse engineering adventure is still ongoing, and eventually, someone is going to play Mario on these things.

The ESP32 is finding its way into all sorts of consumer electronics. Check this thing out. It’s an ESP32, four buttons, and a circular display. If you want to make your own Nest thermostat, or anything else that needs an awesome circular display, there you go.

Speaking of circular displays, are there any non-CRT displays that come with a polar coordinate system? Every circular LCD or OLED I’ve ever seen uses a Cartesian system, which doesn’t really make sense when you can’t see 30% of the pixels.

Hold the phone, this is far too clever. [Eduardo] needed to flash an ESP-12 module before soldering it onto a PCB. The usual way of doing this is with an absurd pogo pin jig. You know what’s cheaper than pogo pins? Safety pins. Clever overwhelming.

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Hackaday Links: November 26, 2017

November 26, 2017 by 11 Comments

Hey, it’s sometime between Black Friday and Cyber Monday. We’re blowing out everything in the Hackaday Store. There’s some great deals in there. Tindie, our lovable robot dog is also heading up hundreds of Tindie deals for Cyber Monday. If you want some electronic stuff direct from the people who make it, this is the sale to check out.

Looking for some other Black Friday/Cyber Monday sales? Adafruit has compiled a list of retailers so I don’t have to. Thanks, Phil. There are deals from Lulzbot to Makerbot, LittleBits to Sparkfun.

The engineer responsible for Dieselgate has been sentenced to 40 months in prison. There are two takeaways from this: 1) The Nuremberg Defense doesn’t work. 2) Don’t build a business plan around breaking the law, despite what the libertarian hellscape of Hacker News tells you.

The theme for next year’s DEF CON has been announced. It’s, “1983”. What does that mean? Brutalist architecture, first of all. They’re also going for a ‘year before 1984’ thing, where everyone installs always-on, far-field microphones in their house and connects them to the Internet. In other news, Alexas and Google Homes are on sale this Black Friday. Big props for the official DEF CON style guide with typefaces and colors, though.

Over on Hackaday.io, [Frank] has created a very interesting and very cool game for the Vectrex. It’s called Bloxorz, and you can think of it as a cross between Marble Madness and Q*Bert. It’s a puzzle game, and now it’s a project on Kickstarter. Want to check out what this game looks like? Take a look at the video. It’s big into the tradition of early-90s puzzle games (a genre we wish would come back), and if I had a Vectrex, I’d buy one.

I told you SparkleCon tickets are on sale, right?

Here’s an argument you can settle. What is the grit designation of sandpaper? Sandpaper comes in various grits, from 60 (very coarse) to 1500, 2000, and 6000 (for polishing, basically). Here’s a question: how are these numbers derived? I have a vague memory from my youth where someone who probably didn’t know what they were talking about said grit sizes are the number of abrasive particles per some unit of area. A 60-grit sandpaper would have sixty particles of aluminum oxide per square quarter inch, for example. This sounds too stupid to be correct, doesn’t fit with the mesh sizes of different grades of sandpaper, and a cursory Googling does not tell me how sandpaper grit sizes are derived. What say you, Hackaday peanut gallery? Where do the numbers on the back of a sheet of sandpaper actually come from?

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Hackaday Links: November 19, 2017

November 19, 2017 by 26 Comments

[Peter]’s homebuilt ultralight is actually flying now and not in ground effect, much to the chagrin of YouTube commenters. [Peter Sripol] built a Part 103 ultralight (no license required, any moron can jump in one and fly) in his basement out of foam board from Lowes. Now, he’s actually doing flight testing, and he managed to build a good plane. Someone gifted him a ballistic parachute so the GoFundMe for the parachute is unneeded right now, but this gift parachute is a bit too big for the airframe. Not a problem; he’ll just sell it and buy the smaller model.

Last week, rumors circulated of Broadcom acquiring Qualcomm for the sum of One… Hundred… Billion Dollars. It looks like that’s not happening now. Qualcomm rejected a deal for $103B, saying the offer, ‘undervalued the company and would face regulatory hurdles.’ Does this mean the deal is off? No, there are 80s guys out there who put the dollar signs in Busine$$, and there’s politicking going on.

A few links posts ago, I pointed out there were some very fancy LED panels available on eBay for very cheap. The Barco NX-4 LED panels are a 32×36 panels of RGB LEDs, driven very quickly by some FPGA goodness. The reverse engineering of these panels is well underway, and [Ian] and his team almost have everything figured out. Glad I got my ten panels…

TechShop is gone. With a heavy heart, we bid adieu to a business with a whole bunch of tools anyone can use. This leaves a lot of people with TechShop memberships out in the cold, and to ease the pain, Glowforge, Inventables, Formlabs, and littleBits are offering some discounts so you can build a hackerspace in your garage or basement. In other TechShop news, the question on everyone’s mind is, ‘what are they going to do with all the machines?’. Nobody knows, but the smart money is a liquidation/auction. Yes, in a few months, you’ll probably be renting a U-Haul and driving to TechShop one last time.

3D Hubs has come out with a 3D Printing Handbook. There’s a lot in the world of filament-based 3D printing that isn’t written down. It’s all based on experience, passed on from person to person. How much of an overhang can you really get away with? How do you orient a part correctly? God damned stringing. How do you design a friction-fit between two parts? All of these techniques are learned by experience. Is it possible to put this knowledge in a book? I have no idea, so look for that review in a week or two.

Like many of us, I’m sure, [Adam] is a collector of vintage computers. Instead of letting them sit in the attic, he’s taking gorgeous pictures of them. The collection includes most of the big-time Atari and Commodore 8-bitters, your requisite Apples, all of the case designs of the all-in-one Macs, some Pentium-era PCs, and even a few of the post-97 Macs. Is that Bondi Blue? Bonus points: all of these images are free to use with attribution.

Nvidia is blowing out their TX1 development kits. You can grab one for $200. What’s the TX1? It’s a really, really fast ARM computer stuffed into a heat sink that’s about the size of a deck of cards. You can attach it to a MiniITX breakout board that provides you with Ethernet, WiFi, and a bunch of other goodies. It’s a step above the Raspberry Pi for sure and is capable enough to run as a normal desktop computer.

Huge 74181 Is A Classic ALU You Can Actually Understand

November 18, 2017 by 22 Comments

You can no longer buy a brand-new 74181, they’ve been out of production for years. All is not lost though, for [Dave’s Dev Lab] have created a facsimile of one on a printed circuit board, using modern single-gate 74-series chips.

Why on earth would you want an oversized replica of an outdated logic chip from nearly five decades ago, we hear you ask? The answer lies in education. If you were to embark on learning about the internals of a microprocessor by taking a modern example such as the one that powers the device on which you are reading this, you would find it to be a daunting task. Over six decades of progress in computer technology have delivered the performance enhancements that put a supercomputer in your smartphone, but at the expense of a contemporary microprocessor being an extremely complex machine which you can’t peer into for any level of understanding.

Simple enough to work your way through the logic

The starting point for the student of microprocessor internals often lies in the past. The technology of the early 1970s holds the fundamentals from which a modern processor can be understood, but remains simple enough to grasp in its entirety as a beginner. Registers, instruction decoders, counters, and an arithmetic/logic unit, or ALU. And for decades the 74181, as an all-in-one 4-bit ALU on a chip that you might have found in a minicomputer at the turn of the 1970s, represented the most convenient way to teach the operation of these devices. Electronic engineers and computer scientists of all ages will have encountered them as they gained their qualifications.

The PCB version of the 181 faithfully follows the original, but with modern 74LVC gates laid out as they would be in the circuit diagram of the chip, and LEDs to show logic state at the different parts of the circuit. Thus when it is used to teach ALU operation it can show every part of the device in detail in a way a real 74181 would never have done.

If the 74181 has caught your interest, we’ve previously brought you [Ken Shirriff]’s reverse engineering of the device in detail using breathtaking images of the silicon.

Modernizing A 170 Year Old Antique Grandfather Clock

November 17, 2017 by 28 Comments

Frankly, we let out a yelp of despair when we read this in the tip line “Antique Grandfather clock with Arduino insides“! But before you too roll your eyes, groan, or post snark, do check out [David Henshaw]’s amazing blog post on how he spent almost eight months working on the conversion.

Before you jump to any conclusions about his credentials, we must point out that [David] is an ace hacker who has been building electronic clocks for a long time. In this project, he takes the antique grandfather clock from 1847, and puts inside it a new movement built from Meccano pieces, stepper motors, hall sensors, LEDs, an Arduino and lots of breadboard and jumper wires while making sure that it still looks and sounds as close to the original as possible.

He starts off by building a custom electro-mechanical clock movement, and since he’s planning as he progresses, meccano, breadboard and jumper wires were the way to go. Hot glue helps preserve sanity by keeping all the jumper wires in place. To interface with all of the peripherals in the clock, he decided to use a bank of shift registers driven from a regular Arduino Uno. The more expensive DS3231 RTC module ensures better accuracy compared to the cheaper DS1307 or similar clones. A bank of RGB LEDs acts as an annunciator panel inside the clock to help provide various status indications. The mechanical movement itself went through several iterations to get the time display working with a smooth movement of the hands. Besides displaying time, [David] also added a moon phase indicator dial. A five-rod chime is struck using a stepper motor driven cam and a separate solenoid is used to pull and release three chime hammers simultaneously to generate the loud gong sounds.

And here’s the amazing part – he did all of this before laying his hands on the actual grandfather clock – which was shipped to him in California from an antique clock specialist in England and took two months to arrive. [David] ordered just the clock housing, dial/face and external parts, with none of the original inner mechanism. Once he received it, his custom clock-work assembly needed some more tweaking to get all the positions right for the various hands and dials. A clock like this without its typical “ticktock” sound would be pretty lame, so [David] used a pair of solenoids to provide the sound effect, with each one being turned on for a different duration to produce the characteristic ticktock.

At the end of eight months, the result – christened Judge – was pretty satisfying. Check the video below to judge the Judge for yourself. If you would like to see some more of [David]’s clockwork, check out Dottie the Flip Dot Clock and A Reel to Reel Clock.

Continue reading “Modernizing A 170 Year Old Antique Grandfather Clock” →

LEDs Give HP 3457A DDM’s LCD Display The Boot

November 15, 2017 by 18 Comments

Have you ever been so frustrated with a digital display that you wanted to rip the whole thing out and create a better one? That is exactly what [xi] did. Replacing their constantly used HP 3457A multimeter’s LCD display with a brighter LED one was a necessary project — and a stress reducing one at that.

While this digital multimeter is well-known for its reliability, its standard display is rather lacking. In fact, there are several mods already out there that simply add a backlight. However, as [xi] notes, LCD screens always have a certain angle where they still don’t quite show properly. So this hack reverses the LCD’s protocol and details the process of creating new LED display.

The issue of dim displays that comes with traditional digital multimeters is not a new one. One solution to this that we have seen before is a hack where someone decided to add a backlight onto their cheap multimeter. [Ken Kaarvik] got around the dimness altogether by giving his multimeter a wireless remote display of his choosing. It is interesting to see the different solutions that are made to the same nuisance. The first item on the agenda of [xi]’s hack was to successfully analyze the HP LCD protocol. With the aid of an ATmega32, the digits were decoded throughout the transmission frames.

Continue reading “LEDs Give HP 3457A DDM’s LCD Display The Boot” →