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In-Band Signaling: Dual-Tone Multifrequency Dialing

September 5, 2017 by 43 Comments

One late night many decades ago, I chanced upon a technical description of the Touch-Tone system. The book I was reading had an explanation of how each key on a telephone sends a combination of two tones down the wire, and what’s more, it listed the seven audio frequencies needed for the standard 12-key dial pad. I gazed over at my Commodore 64, and inspiration hit — if I can use two of the C64’s three audio channels to generate the dual tones, I bet I can dial the phone! I sprang out of bed and started pecking out a Basic program, and in the wee hours I finally had it generating the recognizable Touch-Tones of my girlfriend’s phone number. I held the mouthpiece of my phone handset up to the speaker of my monitor, started the program, and put the receiver to my ear to hear her phone ringing! Her parents were none too impressed with my accomplishment since it came at 4:00 AM, but I was pretty jazzed about it.

Since that fateful night I’ve always wondered about how the Touch-Tone system worked, and in delving into the topic I discovered that it’s part of a much broader field of control technology called in-band signaling, or the use of audible or sub-audible signals to control an audio or video transmission. It’s pretty interesting stuff, even when it’s not used to inadvertently prank call someone in the middle of the night. Continue reading “In-Band Signaling: Dual-Tone Multifrequency Dialing” →

Bye Bye Solaris, It Seems.

September 5, 2017 by 97 Comments

For readers of A Certain Age, this may bring a tear to the eye. Reports have been circulating of the decision by Oracle to lay off a significant portion of the staff behind its Solaris operating system and SPARC processors, and that move spells the inevitable impending demise of those products. They bore the signature of Sun Microsystems, the late lamented workstation and software company swallowed up by the database giant in 2009.

So why might we here at Hackaday be reaching for our hankies over a proprietary UNIX flavour and a high-end microprocessor, neither of which are likely to be found on many of the benches of our readers in 2017? To answer that it’s more appropriate to journey back to the late 1980s or early 1990s, when the most powerful and expensive home computers money could buy were still connected to a domestic TV set as a monitor.

If you received a technical education at a university level during that period the chances are that you would have fairly soon found yourself sitting in a lab full of workstations, desktop computers unbelievably powerful by the standards of the day. With very high resolution graphics, X-windows GUIs over UNIX, and mice that weren’t just used for a novelty paint package, these machines bore some resemblance to what we take for granted today, but at a time when an expensive PC still came with DOS. There were several major players in the workstation market, but Sun were the ones that seemed to have the university market cracked.

You never forget your first love, and therefore there will be a lot of people who will never quite shake that association with a Sun workstation being a very fast desktop computer indeed. Their mantra at the time was “The network is the computer”, and it is the memory of a significant part of a year’s EE students trolling each other by playing sound samples remotely on each other’s SPARCStations on that network that is replaying in the mind of your scribe as this is being written.

A Raspberry Pi with a Raspbian desktop probably outperforms one of those 1980s SPARCStations in every possible way, but that is hardly the point and serves only to demonstrate technological progress. It feels as though something important died today, even if it may be a little difficult to remember what it was when sat in front of a multi-core x86 powerhouse with a fully open-source 64-bit POSIX-compliant operating system running upon it.

Unsurprisingly we’ve featured no hardware hacks with such high-end computing. If you’d like to investigate some Sun Microsystems hardware though, take a look at the Centre for Computing History’s collection.

Non-standard circuit boards

Non-standard Circuits: Jazz For Electrons

September 5, 2017 by 41 Comments

How creative are you when you make your circuit boards? Do you hunt around for different materials to use for the board? As long as it’s an insulator and can handle the heat of a soldering iron, then anything’s fair game. Or do you use a board at all? Let’s explore some options, both old favorites and some you may not have seen before, and see if we can get our creative juices flowing.

Transparent Circuit Boards

Glass circuit board with LED matrix
Glass clock circuit
Triangular part for keytar
Attempted circuit on acrylic

Let’s start with the desire to show more circuit and less board. For that we can start with [CNLohr]’s circuits on glass, usually microscope slides. What’s especially nice about his is that he provides detailed videos of the whole process, including all the failed things he tried along the way. Since he didn’t start with copper clad board, he instead glued his copper sheet to the glass using Loctite 3301. That was followed by the usual etching process, though with plenty of gotchas along the way.

In the end, he made a number of circuits, including an LED clock with the LEDs on the glass itself, and even attempted leading the community in making a glass keytar. The latter didn’t work out, but the resulting glass circuits are a work of art anyway.

What about making a transparent circuit board out of acrylic? [Frank Zhao] attempted just that by laser cutting troughs into the acrylic for the traces, and then drawing in nickel ink. But something in the ink ate into the acrylic, and as if that wasn’t bad enough, the voltage drop across the nickel was too high for his circuit. Suggestions were made in the comments for how to solve these problems, but unless we missed it, we haven’t seen another attempt yet.

But we’ve only just begun. What if you wanted even more transparency?

Continue reading “Non-standard Circuits: Jazz For Electrons” →

Rolling Around A 4th Axis

September 3, 2017 by 23 Comments

[Perry] was interested in adding a 4th axis to his CNC machine, but not very excited at the prospect of spending hundreds of dollars on the parts and electronics to make it work. There is a very clever and very inexpensive way to add a 4th axis to a CNC machine, though, and after a bit of fabrication, he was able to add a ‘rolling’ 4th axis to his machine.

[Bob]’s ‘rolling’ 4th axis.
The idea for this build comes from [Bob] over on the CNC Shark forums. Instead of adding a motor to rotate a work piece around, [Bob]’s build simply mounts it between two jaws, and rolls everything around against the bed of the CNC router. Don’t have a clue what that means? Check out the picture to the right, and you’ll see brilliance built in Delrin and HDPE.  By mounting two rack gears to the bed and two geared jaws to the carriage of the machine, moving the router in the Y axis also rotates the 4th axis. This is far, far too clever; it doesn’t require any additional electronics and the only software tweaks are a bit of G-code hacking.

[Perry] took one look at [Bob]’s project and decided this would be the perfect build to get him a 4th axis. The parts for this build were fabricated out of black HDPE, with the only real change to the design being a ‘variable length’ 4th axis. Instead of two rack gears mounted to the bed of the machine, [Perry]’s build only uses one rack, with the other end simply rolling on the bed.

There are a lot of clever inventions that don’t work, so what’s the verdict with this CNC hack? It actually looks pretty good. [Perry] was able to turn some square stock into round stock, and able to engrave a spiral around a cylinder. You can check out those videos below.

Continue reading “Rolling Around A 4th Axis” →

Make Cars Safer By Making Them Softer

September 3, 2017 by 78 Comments

Would making autonomous vehicles softer make them safer?

Alphabet’s self-driving car offshoot, Waymo, feels that may be the case as they were recently granted a patent for vehicles that soften on impact. Sensors would identify an impending collision and adjust ‘tension members’ on the vehicle’s exterior to cushion the blow. These ‘members’ would be corrugated sections or moving panels that absorb the impact alongside the crumpling effect of the vehicle, making adjustments based on the type of obstacle the vehicle is about to strike.

Continue reading “Make Cars Safer By Making Them Softer” →

Stunning Fake Polaroid Camera Performs Magic

August 31, 2017 by 39 Comments

It’s high time us Muggles got our hands on the hardware used to take Magical Photographs as seen in The Daily Prophet. The first pioneering step in that direction has been taken by [Abhishek] who built this moving picture taking polaroid-ish camera, which he’s calling the “Instagif NextStep”. It’s a camera that records a short, three second video, converts it to GIF and ejects a little cartridge which displays the animated photo.

This amazing piece of hardware has been painstakingly built, and the finished product looks great. The nice thing about building such projects, in [Abhishek]’s own words, is that “it involves a bunch of different skill sets and disciplines – hardware, software, 3D modeling, 3D printing, circuit design, mechanical/electrical engineering, design, fabrication etc that need to be integrated for it to work seamlessly.”
Continue reading “Stunning Fake Polaroid Camera Performs Magic” →

Way To Go, Einstein; His Time Spent Being Wrong

August 31, 2017 by 116 Comments

When you hear someone say “Einstein”, what’s the first thing that pops into your head? Is it high IQ… genius… or maybe E=MC2? Do you picture his wild grey hair shooting in all directions as he peacefully folds the pages back from his favorite book?  You might even think of nuclear bombs, clocks and the Nobel Prize. It will come as a surprise to many that these accomplishments were a very small part of his life. Indeed, Einstein turned the world of classical physics upside down with his general theory of relativity. But he was only in his early twenties when he did so.

What about the rest of his life? Was Einstein a “one-hit-wonder”? What else did he put his remarkable mind to? Surely he tackled other dilemmas that plagued the scientific world during his moment in history. He was a genius after all… arguably one of the smartest people to have ever walked the earth. His very name has become synonymous with genius. He pulled the rug out from under Isaac Newton, whose theories had held the universe together for over 300 years. He talked about enigmatic concepts like space and time with an elegance that laid bare the beauty hidden within their simplicity. Statues have been made of him. His name and face are recognizable across the globe.

But when you hear someone say “Einstein”, do you think of a man who spent the better half of his life… being wrong?  You should.

Continue reading “Way To Go, Einstein; His Time Spent Being Wrong” →