The Conductive Paper That Sparked A Revolution

September 28, 2015 by Kristina Panos 27 Comments

Legendary electrical engineer and linear IC trailblazer Bob Widlar was just like you. What I mean is that he would use everything available to him to mock up circuits, create prototypes, and make things work. One of the simplest and coolest tools he used was a conductive paper called Teledeltos. This wonderful stuff allowed him to define and test various configurations for the oddly-shaped ballast resistors he used in some of his high-performance circuit designs. But it wasn’t created for people like you and Bob. Teledeltos paper was created and trademarked by communications giant Western Union to drastically improve the convenience of telegrams.

Development of the electric telegraph ushered in the era of global communication. Suddenly, people could send messages to the other side of the world in a fraction of the time it took by post. The telegraph absolutely revolutionized human communication. It was the e-mail and the Twitter of its time. The telegraph’s efficiency made the Pony Express pretty much obsolete by the 1860s. And for a very long time it was much cheaper for people to send a telegram than make a long-distance phone call.

The Advantages of Facsimile

Translated from ancient Greek, ‘teledeltos’ basically means writing tablet at a distance. Western Union began developing Teledeltos paper in the 1930s for the purpose of transmitting telegrams by facsimile, a method that would greatly reduce the time it took to input messages into the system and get them out on the other side. As long as both the sender and the receiver had facsimile machines, a handwritten telegram could be transmitted without having to be typed by a clerk or translated into code. Teledeltos paper was also used in a variety of chart recorders, like seismographs and map plotters. The ability to feed a handwritten message, a photograph, or a map of enemy territory into a machine that transmitted an exact copy was a real game changer.

Because of its composition, Teledeltos paper could be easily marked without an electrolyte. It marked so well that photographs and other graphic information could be transmitted, and no processing was required on the receiving end. A dry recording paper is also much less sensitive to light and to temperature extremes. More importantly, properly stored dry paper is impervious to fungal growth. Teledeltos paper could sit around indefinitely without becoming useless. The only real disadvantage to this type of paper was the somewhat laborious process that went into achieving the desired resistance. Fax machines eventually moved on to digital transmission and thermal printing technology.

Sparking a Revolution

Teledeltos paper has a light gray electro-sensitive coating on one side, and the other side is carbon black. When a current is applied with a stylus to the coated side of the paper, the coating is instantly burned away, revealing the carbon black. Teledeltos paper could be marked using either AC or DC. Polarity didn’t matter, either, but the boys in the lab at Western Union had better luck when they used a positive stylus with DC rather than a negative one.

Teledeltos paper was made in two types—“L” for low resistance and “H” for high. The resistivity of a roll of Teledeltos paper depended on the quality of the conductive fibers that went into it. The paper’s electrical characteristics were also influenced by the fiber beating process and the distribution of the conductive fibers by the supercalender, a system of hard rollers used in papermaking and other processes that press and smooth paper and other materials to increase the density.

Teledeltos to the Rescue

The Western Union Telecar printed telegrams on the go and delivered them to homes and businesses. Image credit: Modern Mechanix

Western Union was eager to extend its reach into private businesses and public places so that patrons who weren’t heavy telegram users didn’t have to visit a telegram office in order to share a bit of good news or to send their condolences. The company’s Telefax division came up with several types of machines to serve different business needs.

Some messages continued to be delivered by hand, but they weren’t printed at the central office. Western Union created a Telecar service to print telegrams transmitted to the car by the central office and deliver them to people’s homes. Messages were printed onto recording blanks that were cut automatically by a Telefax recorder situated in the car’s passenger area. The Telecar’s radio and amplification equipment was in the trunk.

The standard Telefax machine for office use was fairly large, like an early microwave oven. A smaller version called the DeskFax was only about the size of a breadbox, and these units occupied the desks of many businessmen and secretaries because of their convenience.

A Western Union DeskFax unit. Image from [B. Hilpert]http://www.cs.ubc.ca/~hilpert/e/deskfax/ — A Western Union DeskFax unit. Image from [B. Hilpert]

Both the Telefax and the DeskFax scanned and recorded telegrams using a rotary drum mechanism. A message could either be typed or handwritten onto a telegram blank. The sender then wrapped the telegram around a drum and set the machine to send. The machine would scan the message optically and then transmit it to the central office.

Before sending it on to the recipient, an attendant at the telegram office had to remove the incoming message and wrap it around the drum of a transmitting machine. Once connected to the receiving party’s line, the far end unit would buzz to arouse attention. The receiving patron would then load a blank on to their DeskFax’s roller and set their machine to receive.

Teledeltos for Hacking and Education

Measuring potential differences. Image from https://physics.ucsd.edu/students/courses/summer2010/physicslabs/SS2101BLLab03.pdf — Measuring potential differences.
Image from UCSD

Conductive paper like Teledeltos has many applications aside from fax machines and Fathometers. For starters, it’s great for making one-offs of both standard and variable resistors. Conductive paint can be used as connection points for wires. The paper is also well-suited for simulating current flow through circuits using a fraction of the current intended in production. Vacuum tube designers used Teledeltos for modeling potentials. Teledeltos can also be used to visualize electromagnetic potentials and perform field plotting.

We’re sure that at least a few of our readers out there used Teledeltos or something like it in school or on the job. Did you know you can still buy it? Teledeltos paper itself is still available from two companies in the UK, Better Equipped and Timstar. In the US, you can get it from Pasco in packs of 50 and 100 sheets, with and without a grid pattern.

[Teledeltos paper image is a product photo from Better Equipped]

The Netflix And Chill Button

September 27, 2015 by Brian Benchoff 57 Comments

While the people at Netflix were busy killing weekends around the world with marathon viewings of 90s sitcoms, they also found time to release the Netflix Switch. It’s a small device with a single button that will control your TV, turn off the lights, and order a pizza. Remember, time you enjoy wasting is not wasted time.

The Netflix Switch is a relatively simple device powered by a Particle Core, an Arduino-compatible development board with on-board WiFi. Also in this box is a LiPo battery, a few LEDs, and an IR transmitter that will send the same IR signal as the Netflix button on your TV remote, should your remote have a Netflix button.

In an unprecedented break from reality, this astute corporate branding of electronics tinkering also has design files, schematics, and real instructions that come along with it. Netflix released all of the mechanical files for their switch in Solidworks format; for the low, low price of only $4000 per Solidworks license, you too can Netflix and Chill.

Although Netflix’ implementation of tapping into a DIY electronics movement that has been around for 100 years is lacking, the spirit of the build is laudable. A single button connected to the Internet is a universal tool, and whether you want to order a pizza or make a ‘do not disturb’ button for your phone, the only limitation for the Netflix and Chill button is your imagination.

Hacking When It Counts: GI Ingenuity

September 25, 2015 by Dan Maloney 59 Comments

For most of us, hacking is a hobby, a pleasant diversion from reality. Yes, a lot of us work on projects which have the potential to change the world – witness the 2015 Hackaday Prize semifinalist list. But in general, almost any of us could walk away from the shop at any time without dire consequences. Indeed, that’s the reason a lot of our work benches are littered with projects started with the best of intentions but left unfinished for lack of funds, lack of interest, or lack of time. We’re free to more or less willingly shelve a project and come back to it whenever we please, or not at all.

But not everyone has that luxury. For some people, hacking is much more than a hobby – it’s a means of survival. Sometimes people are thrown into situations where they have to cobble together a solution to an immediate problem with whatever is at hand, when the penalty for failure is much higher than a cluttered bench and a bruised ego. I’ve already covered one such case, where biohacked insulin saved hundreds of lives in occupied Shanghai in WWII.

In this occasional series I’ll explore historical cases where hacking really counted; cases where lives were saved or improved by a hack performed under desperate conditions.

A Bustle in the Hedgerow

Unsurprisingly, war offers a lot of opportunities for field expedient solutions under dire circumstances, and battlefield conditions might be the most extreme example of hacking when it counts.

In the early days of the Invasion of Normandy during WWII, Allied forces were having a difficult time dealing with the bocage terrain of northern France. A mixture of pasture and woodland, the Normandy bocage was a natural killing field for Allied tanks because the woodlands took the form of hedgerows – earthen dikes topped with thick tangles of brush. Hedgerows separated pastures and kept livestock controlled, but also made things tough on infantry and mechanized cavalry alike. Climbing the steep hedgerows exposed the vulnerable bottom hull of the tanks to enemy fire, and waiting for engineers to demolish the hedgerows with explosive made them sitting ducks for German artillery. The Allied advance was seriously hampered by the hedgerows, and both men and materiel were being winnowed down from fixed German positions chosen specifically to take advantage of the bocage terrain.

curtis cullin — Sgt. Curtis G. Culin (source: Cranford (NJ) Patch)

Enter Sgt. Curtis Grubb Culin III. Sgt. Culin, a tanker himself, was acutely aware of how vulnerable he was in his Sherman M4. The hedgerows were the problem, one apparently known to Allied command prior to the invasion for which no provision had been made. In the tradition of soldiers at the front of every battle throughout history, Sgt. Culin and his fellow tankers had to improvise a solution.

While kicking around ideas, one of the men suggested setting saw teeth on the front of a tank to cut through the hedgerows. He later attributed the comment to “A Tennessee hillbilly named Roberts”, and it was met with general laughter from the group as a crackpot scheme. But Sgt. Culin saw the potential in the idea, and began to develop it into a prototype.

Yanks_of_60th_Infantry_Regiment_advance_into_a_Belgian_town_under_the_protection_of_a_heavy_tank._-_NARA_-_531213 — Rhino-equipped tank (source: Wikipedia)

Raw materials for his prototype were not hard to come by. Czech hedgehogs, giant anti-tank barriers made of crossed steel beams, still littered the Normandy beaches. The failed German defenses were harvested with a cutting torch and welded to the underside of a tank to form a series of “tusks” across the hull between the tracks. Equipped with these tusks, the tank could now blast through the tangled roots of the brush-covered earth of the hedgerow dykes.

When demonstrated for General Omar Bradley, he was impressed enough to order them built in quantity for the tanks. Eventually the prototype became an engineered product (dubbed the “Culin Rhino Device”) that was fitted to many tanks before being shipped over from England. Rhino-equipped tanks ripped across Normandy and shredded the German battle plan, which assumed the hedgerows would funnel Allied forces through heavily defended chokepoints.

Without Sgt. Culin’s battlefield hack, and his inspiration by a hillbilly named Roberts whom history otherwise forgets, the invasion of Europe might have taken a very different course. The fact that he did the hack while under fire makes it all the more impressive, and is a perfect example of hacking when it counts.

Know of any more examples of hacking when it counts? Send us a tip for use in a future Hacking When it Counts article.

[Main image of Czech Hedgehog by Jesse CC-BY-SA 3.0]

Hackaday Dictionary: The ESP8266

September 24, 2015 by Richard Baguley 40 Comments

In August of 2014, something new started showing up in the markets of Shenzhen, the hi-tech area of China where the majority of the world’s electronics components are made. This is the ESP8266, a WiFi SoC (System on a Chip) that can connect to 802.11b/g/n networks on the 2.4GHz band. It can be addressed with SPI or a serial connection, and has an AT command set that makes it behave rather like an old-style modem. Basically, it has everything you would need to connect a device to a WiFi network, with the ESP8266 chip itself handling the complicated business of finding, joining and transmitting/receiving over a WiFi network.

That’s nothing particularly new in itself: WiFi connection devices like the TI CC3000 have been around for longer, and do much the same thing. The difference was the price. While the TI solution costs about $10 if you buy several thousand of them, the ESP8266 costs less than $7 for an individual board that can plug straight into an Arduino or similar. Buy the chip in bulk, and you can get it for less than $2.

The ESP8266 is more than just a WiFi dongle, though: it is a fully fledged computer in itself, with a megabyte of flash memory and a 32-bit processor that uses a RISC architecture. This can run applications, turning the ESP8266 into a standalone module that can collect and send data over the Internet. And it can do this while drawing a reasonably low amount of power: while receiving data, it typically uses just 60mA, and sending data over an 802.11n connection uses just 145mA. That means you can drive it from a small battery or other small power source, and it will keep running for a long time.

It wasn’t an easy ship to write applications for in the early days, though: it was poorly documented and required a dedicated toolchain to work with. This made it more of a challenge than many hackers were comfortable with. That changed earlier this year, though, when the Arduino IDE (Integrated Development Environment) was ported to the chip. This meant that you could use the much easier to write Arduino functions and libraries to write code for the chip, bringing it within reach of even the most casual hacker.

Continue reading “Hackaday Dictionary: The ESP8266” →

Ethics In Engineering: Volkswagen’s Diesel Fiasco

September 23, 2015 by Brian Benchoff 360 Comments

Every so often – and usually not under the best of circumstance – the field of engineering as a whole is presented with a teaching moment. Volkswagen is currently embroiled in a huge scandal involving emissions testing of 11 Million diesel cars sold in recent years. It’s a problem that could cost VW dearly, to the tune of eighteen Billion dollars in the US alone, and will, without a doubt, end the careers of more than a few Volkswagen employees. In terms of automotive scandals, this is bigger than Unsafe at Any Speed. This is a bigger scandal than the Ford Pinto’s proclivity to explode. This is engineering history in the making, and an enormously teachable moment for ethics in engineering.

Continue reading “Ethics In Engineering: Volkswagen’s Diesel Fiasco” →

Why Are You Still Making PCBs?

September 21, 2015 by Al Williams 223 Comments

Few things have had the impact on electronics that printed circuit boards (PCBs) have had. Cheap consumer electronics would not be as cheap if someone still had to wire everything (although by now we’d be seeing wiring robots, I’m sure). Between removing the human from the wiring process and providing many excellent electrical properties (at least, on a well-designed board), it isn’t surprising that even the cheapest examples of electronics now use PCBs.

For many years, the hallmark of being a big-time electronic hacker was the ability to make your own PCBs. There have been many ways that people have tried to bring PCB manufacturing into the hacker’s garage: stick on decals, light-sensitive blank PCBs, and even using laser printer toner (that last one spurred me to write a book on PCB layout many years back). You also see a lot of people using 3D printers or CNC mills to create PCBs. Hardly a week goes by that someone doesn’t ask me how to make a PCB in a home or small business lab.

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This Is What A Real Bomb Looks Like

September 21, 2015 by Adam Fabio 403 Comments

In 1980, Lake Tahoe, Nevada was a popular tourist spot. The area offered skiing, sailing, hiking in the mountains, and of course, gambling on the Nevada side of the lake. It was in this somewhat unlikely place where the authorities found the largest improvised bomb seen to that date in the USA.

Harvey’s casino was opened by former butcher Harvey Gross in 1944. In less than 20 years it grew to a 192 room, 11 story hotel casino. Thousands of people played Harvey’s slot machines and table games. Some were winners, but most were losers. John Birges was one of the latter. Formerly a successful landscaping company owner worth millions, he lost all of it to his gambling addiction.

Born in Hungary in 1922 as János Birges, John grew up in Budapest. When WWII hit, he flew an Me-109 for the Luftwaffe. He was arrested by the Gestapo for disobeying orders during the war, but was released. After the war, he again found himself in hot water – this time with the Russians. He was arrested in 1948 and charged with espionage. His sentence was 25 years of hard labor in the Gulag. The stories vary, but most agree that Birges was able to escape his work camp by detonating a bomb as a diversion.

In 1957 Birges and his wife Elizabeth immigrated to California. He changed his name from János to John to fit in. The couple had two sons, Johnny and Jimmy. John built up a successful landscaping business and bought a restaurant, working his way into the millionaires’ club. From the outside, they were the perfect example of the American dream.

Appearances can be deceiving. Behind closed doors, Birges was a right bastard to his family. He beat his wife and his children, even forcing them to kneel on gravel when they disobeyed him. Eventually, Johnny left home to escape his father’s fists. Elizabeth filed for divorce, and was later found dead under mysterious circumstances. Birges began gambling heavily, especially at Harvey’s Wagon Wheel casino in Lake Tahoe. He eventually burned through his personal savings, as well as the income from his businesses. The once millionaire was now penniless, but he had a plan. Just as a bomb had helped him escape the Gulag, he’d use a bomb to extort his money back from Harvey’s.

Continue reading “This Is What A Real Bomb Looks Like” →