Cable Butchering For Logic-Level Serial

Early PCs and other computers had serial ports, sometimes as their main interfaces for peripherals. Serial ports still survive, but these days they are more likely to have a USB connection into the main computer. However, when you are working with a microcontroller, you probably don’t want a proper RS232 port with its plus and minus 12 volt signals.

You can get converters that specifically output logic-level signals but you probably can’t pick one up at the local office supply store. They might, though, have a normal USB to serial cable. [Aaron] had the same problem so he hacked into a cable to pull out the logic level signals.

On the one hand, hacks like this are a good inspiration for when you have a similar problem. On the other hand, you probably won’t wind up with the same cable as [Aaron]. He got lucky since the board inside his cable was clearly marked. Just to be sure, he shorted the transmit and receive lines to see that he did get an echo back from a terminal program.

Unsurprisingly, you can also repurpose an ESP8266 to perform this same task. Or, you can use a cable as an I/O device.

Filed under: Microcontrollers

Gutting And Rebuilding A Classic Watch

No, that watch isn’t broken. In fact, it’s better.

[Lukas] got so used to his binary-readout ez430 Chronos watch that when the strap disintegrated he had to build his own to replace it. But most DIY wristwatches are so clunky. [Lukas] wanted something refined, something small, and something timeless. So he shoe-horned some modern components, including an MSP430, into a Casio F-91W watch.

The result is a watch that tells time in binary, has a built-in compass, and with some more work will be updatable through an IR receiver that he also managed to fit in there somehow. Now he has the watch that Casio would make today, if fashion had stayed stuck firmly in the early 1990s. (Or not. Apparently, Casio still makes and sells the F-91W. Who knew?)

Anyway, back to an epic and pointless hack. Have a look at the tiny, tiny board that [Lukas] made. Marvel in the fact that he drove the original LCD screen. Dig the custom Kicad parts that match the watch’s originals. To get an accurate fit for the case, [Lukas] desoldered the piezo buzzer contact and put the board onto a scanner, which is a great trick when you need to get accurate dimensions. It’s all there, and well-documented, in his GitHub, linked above.

All in all, it’s an insane hack, but we love the aesthetics of the result. And besides, sometimes the hacking is its own reward.

Filed under: clock hacks

Hackaday Dictionary: Software Defined Radio (SDR)

We are entering a new era of radio technology. A new approach to building radios has made devices like multi-band cell phones and the ubiquitous USB TV receivers that seamlessly flit from frequency to frequency possible. That technology is Software Defined Radio, or SDR.

A idealized radio involves a series of stages. Firstly, an antenna receives the radio signal, converting it into an electrical signal. This signal is fed into a tuned resonator which is tuned to a particular frequency. This amplifies the desired signal, which is then sent to a demodulator, a device which extracts the required information from the carrier signal. In a simple radio, this would be the audio signal that was encoded by the transmitter. Finally, this signal is output, usually to a speaker or headphones.

A replica foxhole crystal set. Photo: Bill Jackson
A replica foxhole crystal set. Photo: Bill Jackson

That’s how your basic crystal radio works: more sophisticated radios will add features like filters that remove unwanted frequencies or additional stages that will process the signal to create the output that you want. In an FM radio, for example, you would have a stage after the demodulator that detects if the signal is a stereo one, and separates the two stereo signals if so.

To change the frequency that this radio receives, you have to change the frequency that the resonator is tuned to. That could mean moving a wire on a crystal, or turning a knob that controls a variable capacitor, but there has to be a physical change in the circuit. The same is true of the additional mixing stages that refine the signal. These circuits may be embedded deeply in the guts of the radio, but they are still there. This is the limitation with normal receivers: the radio can’t receive a signal that is outside the range that the resonator circuit can tune to, or change the way it is demodulated and processed. If you want to receive multiple frequency bands or different types of signals, you need to have separate pathways for each band or type of signal, physically switching the signal between them. That’s why you have physical AM/FM switches on radios: they switch the signal from an AM radio processing path to an FM one.

Software Defined Radios remove that requirement. In these, the resonator and demodulator parts of the radio are replaced by computerized circuits, such as analog to digital converters (ADCs) and algorithms that extract the signal from the stream of data that the ADCs capture. They can change frequencies by simply changing the algorithm to look for another frequency: there is no need for a physical change in the circuit itself. So, an SDR radio can be tuned to any frequency that the ADC is capable of sampling: it is not restricted by the range that a resonator can tune to. Similarly, the demodulator that extracts the final signal you want can be updated by changing the algorithm, changing the way the signal is processed before it is output.

This idea was first developed in the 1970s, but it didn’t really become practical until the 1990s, when the development of flexible field-programmable gate array (FPGA) chips meant that there was enough processing power available to create single chip SDR devices. Once programmed, an FPGA has no problem handing the complex tasks of sampling, demodulating and processing in a single device.

Most modern SDRs don’t just use a single chip, though. Rather than directly converting the signal to digital, they use an analog front end that receives the raw signal, filters it and converts it down to a fixed frequency (called the intermediate frequency, or IF) that the ADCs in the FPGA can more easily digitize. This makes it cheaper to build: by converting the frequency of the signal to this intermediate frequency, you can use a simpler FPGA and a cheaper ADC, because they don’t have to directly convert the maximum frequency you want to receive, only the IF. As long as the front end can convert a band of signals down to an intermediate frequency that the FPGA can digitize, the SDR can work with it.

The BladeRF, a modern SDR device that can receive and transmit signals between 300 MHz and 3 GHz

This flexibility means that SDR devices can handle a huge range of signals at relatively low cost. The $420 BladeRF, for instance, can receive and transmit signals from 300 MHz to 3.8 GHz at the same time, while the $300 HackRF One can work with signals from 1 MHz up to an incredible 6 GHz. The ability of the BladeRF to both receive and transmit means that you can use it to build your own GSM phone network, while the low cost of the HackRF One makes it a favorite of radio hackers who want to do things like make portable radio analyzers. Mass produced models are even cheaper: by hacking a $20 USB TV receiver that contains an SDR, you can get a radio that can, with a suitable antenna, do things
like track airplanes or receive satellite weather images. And all of this is possible because of the idea of Software Defined Radio.

[Main image source: DVB dongle by Dsimic on Wikipeda CC-BY-SA]

Filed under: Hackaday Columns, news

A Barcade And Hackerspace, All In One

Hamvention was last weekend, and just like Hackaday’s expedition to Maker Faire, it was only fitting to find a bunch of Hackaday fans and take over a bar. This was in Dayton, Ohio, and you would think the nightlife for Hamvention would be severely lacking. Not so, as downtown Dayton is home to Proto BuildBar, a bar, arcade, and hackerspace all wrapped into one.

We’ve heard about Proto BuildBar a few years ago when it first opened. The idea is relatively simple; instead of having a hackerspace, with alcohol and video games on the side, Proto BuildBar is first and foremost a bar, with 3D printing services, a few workstations for soldering, and a few arcade games. It’s the perfect place for an impromptu meetup.

A Very Big Claw Machine

Somewhere on a corner in downtown Dayton, Ohio is a world record holder. It’s the world’s largest crane game. Those arcade machines with a joystick, a bin full of stuffed animals, and a tiny little crane? Yeah, the largest one of those. It’s $5 a go, and the prizes are either large inflatable balls, or the rare large hamster ball with a t-shirt inside.

The claw rides along a fairly standard steel track, using skateboard bearings
An electric wheelchair motor

For a world record, the world’s largest claw machine is surprisingly simple. It’s really just angle iron, an electric wheelchair motor, and a few large motor drivers. The joystick, while very large, uses standard arcade button switches. It’s an extremely impressive build, but you’re immediately struck by how easy this would be to replicate.

3D Printing And Soldering

Proto BuildBar is loaded up with 3D printers, mostly Makerbot, including a single Thing-O-Matic that actually works. That, in itself, is exceedingly rare. Anyone can walk in off the street and have something printed. The price is about $10 for each hour of machine time – slightly expensive if you’re using this as a tool, but just about right for an ‘introduction to 3D printing’ that is so desperately needed among the general population.

An Arcade

Saturday night is apparently Proto BuildBar’s gaming night, and for that they trucked out a few classic gaming consoles onto a few tables. It was SNES, Genesis, and Sega CD all the way, and a few multicade bartop and standup units. By far the most impressive arcade machine is War of the Currents, a custom arcade game featuring a Street Fighter style rendition of the greatest battle of all time: Edison vs. Tesla.

War of the Currents is your standard fighting game. It does have one trick up its sleeve, though: the loser is shocked. Literally, through a conductive joystick.


War of the Currents wasn’t at Proto BuildBar during the impromptu Hackaday meetup. It was sleeping quietly while Hamvention was closed. I got to play it with some of the guys from Proto BuildBar, and yes, this is a proper, shocking Street Fighter clone.

What’s Proto BuildBar like? Great. If you’re in the area, you should check it out. If Hackaday heads out to Hamvention next year, we know where to plan our meetup.

Filed under: cons

Hackaday Prize Needs You: Build for Citizen Scientists

Humanity is better when we work together. Nowhere is this more true than when it comes to Citizen Scientists — the concept that scientific advancement isn’t reserved to the trained professionals, but benefits when a larger population of thinkers collaborates with the community of trained researchers. This is the goal of the Citizen Scientist challenge round for the Hackaday Prize. Let’s build something that enables citizens to be scientists.

We’ll divide $20,000 evenly between twenty projects that target Citizen Scientists. Enter now and build your prototype by July 11th for your chance to win. Even better, if you are selected as one of those 20 finalists you’ll compete for the top prizes, $150k and a residency at the Supplyframe Design Lab in Pasadena. Second through fifth place finishers will get $25k, $10k, $10k, and $5k.

ramanPi You love design challenges and this one has powerful potential. We’ve seen builds like this in the finals during previous years of the Hackaday Prize. In 2014, RamanPi was recognized as the 5th place winner. The project seeks to reduce the expense of acquiring a Raman Spectrometer which is used for analyzing chemical substances. The design used parametric models for the optic jigs used by the machine. The idea is that a university could buy their own optics, adjust the models for the properties of those lenses and mirrors, then 3D print the parts to build the apparatus.

open-science-tricorderAlso a winner in 2014, the Open Science Tricorder was recognized as the fourth place finisher. Based on the form factor and functionality of the iconic Star Trek technology, the Open Science Tricorder combines three or more sensor technologies with a user interface. It provides a hands-on experience for students learning about the properties of the world around them, and a handheld sensor suite to anyone interested in undertaking their own research projects.

The Citizen Scientist challenge round begins right now. Get started on your build today and show us what you can do to solve a technology problem with your prototyping skills. Good luck!

The HackadayPrize2016 is Sponsored by:

Filed under: Hackaday Columns, The Hackaday Prize

Pixelmator 3.5

Adds the Quick Selection Tool and Magnetic Selection Tool, plus a new Pixelmator Retouch Extension for Photos. ($29.99 new, free update, 54.4 MB)


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Making Springs At Home

[This Old Tony] teaches us how to make springs on a lathe in this video done in the style of How It’s Made. Mixed in with snark, in his usual style, is a lot of useful information.

The Machinery’s Handbook certainly has all the information one would need to design the basic spring shapes, but it’s not always necessary. [Tony] points out that cheating is entirely acceptable. For example, if you need a spring that’s close to the dimensions of a standard spring, simply copy over the values from the standard spring. He explains all the terminology needed to decrypt the pages in your engineering tome of choice.

He shows the basics of winding a spring on a mandrel (or that round metal thing, if you want to use the industry term). First wind the inactive coils, then set your lathe to the desired spring pitch. Engage it as if threading, then disengage and wind the final inactive coils. A quick trip to the sander squares the ends of a standard coil spring. However, the tools can also be used to make torsion springs, or even exotic combination springs.

For a good… educational laugh, watch the whole video after the break.

Filed under: hardware

Hackaday Links: May 29, 2016

Hackaday has a store‽ Yes, it’s true, and we have a Memorial Day sale going on right now. Get a cool robot had t-shirt, a cool clock, or a GoodFET. Spend money. Consume.

Learn COBOL. Seriously, you should learn COBOL. It’s a fact of nature that every computer-minded person will eventually hear that COBOL developers make bank, and you’ll have job security for the rest of your life. Now look at the Hello World for COBOL. Yes, there’s a reason COBOL devs make bank, and they’re still vastly underpaid. [Folkert] figured a way around this problem: he built a Brainfuck to COBOL compiler. Mainframe programming for the rest of us.

[fbustamante] got his hands on an old GP2X Wiz, one of those ARM-based portable media player/emulator things from a few years ago. This is a complete computer, and like the Pandora, it’ll do everything one of those Raspberry Pi laptops can do. The Wiz doesn’t have a keyboard, so [fbustamante] created his own. He etched his own PC, repurposed a keyboard controller from a USB keyboard, and stole the keycaps from an old Sharp digital organizer.

Speaking of portable consoles, [Element18592] built this incredible Nintendo 64 portable. He’s done an XBox 360 laptop and stuffed a Pi into an old brick Game Boy. This N64 mod is great, uses a 3D printed enclosure, and has truly amazing vinyl graphics.

To the surprise of many, [Photonicinduction] is not dead. The drunk brit with a penchant for high voltage electrics and a very, very confused power company is back making videos again. His latest video is a puzzle. It’s a plastic block with a light bulb socket, a UK power outlet, and a switch. Plug in a light bulb, flip the switch, and it turns on. Plug a blender into the outlet, and that turns on too. No wires, so how is he doing it?

Introduced at CES last January, Monoprice – yes, the same place you get HDMI and Ethernet cables from – has released their $200 3D printer. This one is on our radar and there will be a review, but right away the specs are fantastic for a $200 printer. The build area is 120mm³, it has a heated bed, and appears to be not completely locked down like the DaVinci printers were a few years ago.

Filed under: Hackaday Columns, Hackaday links

Toa Mata Lego Band Actually Rocks

[Opificio Sonico] has been at the Lego-based robot music making business for a while now, and it shows. He’s released four videos on YouTube (all inlined below) and each shows a definite evolution of his style and the Lego ‘bots technical range.

Episode 4, a cover of Daft Punk’s “Alive”, is clearly the most polished. A sliding platform goes enables a Lego “Toa Mata” figure to play the melody on some kind of iDevice (?). The ‘bot playing the DS to hit its one note repeatedly with the stylus, and has an easier job thanks to Daft Punk’s compositional “efficiency”. Episode 3, Depeche Mode’s “Everything Counts” is fantastic, partly because he’s using piezo-miced junk as percussion (as did DM themselves) and partly because of the sliding stylophone. But watch them all.

There’s some serious production work going on here in addition to the obvious nerdery. Oh yeah, and there’s an Arduino buried in there somewhere doing the MIDI-to-Lego conversion. Toa Mata Band is nowhere near as metal as Compressorhead, but pound for pound, we’d give them the advantage.

Thanks [Johnyy] for the tip! How have we never covered these plastic guys before?

Filed under: musical hacks

Dragging Teletypes Into The 21st Century

If you are of a certain age you may have worked in an office in the days before the computer revolution, and the chances are that in the corner of your office there would have been a teletype machine. Like a very chunky typewriter with a phone attached, this was an electromechanical serial terminal and modem, and machines like it would have formed the backbone of international commerce in the days before fax, and then email.

Teletypes may have disappeared from the world of trade, but there are a surprising number still in private hands. Enthusiasts collect and restore them, and radio amateurs still use digital modes based on their output. The problem facing today’s teletype owner though is that they are becoming increasingly difficult to interface to a modern computer. The serial port, itself an interface with its early history in the electromechanical world, is now an increasingly rare sight.

[Eric] has a project which addresses the teletype owner’s interfacing woes, he’s created a board with all the necessary level shifters and an Atmega32u2 microcontroller to translate the teletype’s output to USB.

In his design he’s had to solve a few problems related to such an aged interface. Teletypes have a serial output, but it’s not the TTL or RS232 we may be used to. Instead it’s a high-voltage current loop designed to operate electromagnets, so his board has to incorporate an optocoupler to safely isolate the delicate computer circuitry. And once he had the teletype’s output at a safe level he then had to translate its content, teletypes speak 5-bit ITA2 code rather than our slightly newer 7-bit ASCII.

The result though is a successful interface between teletype and computer. The former sees another teletype, while the latter sees a serial terminal. If you have a teletype and wish to try it for yourself, he’s released the source code in a GitHub repository.

Teletypes have featured a few times here at Hackaday over the years. We’ve had one as an SMS client, another that monitors a Twitter feed, and while it’s not strictly a teletype, a close examination of an Olivetti mechanical serial terminal.

Filed under: classic hacks, hardware