Turning OLEDs And Acrylic Into Faux Nixie Tubes

Love ’em or hate ’em, Nixies and the retro clocks they adorn are here to stay. At least until the world’s stock of surplus Soviet tubes is finally depleted, that is. The glow discharge tubes were last mass manufactured in the 1980s, and while they’re not too hard to get a hold of yet, they will be eventually. And what better way to get ready for that dreaded day than by rolling your own OLED faux Nixie tubes?

Granted, [Derek]’s faux Nixies, appropriately dubbed “Fixies,” require just a touch of willing suspension of disbelief. We’ve never see Nixies with tiny jam jars as envelopes, so that’s probably the first giveaway. But looking past that, the innards of these fake displays do a pretty convincing job of imitating the texture of the real thing.

The numbers themselves are displayed on a 128×64 white OLED display using a Nixie-like True Type font. An orange acrylic filter in front of the display gives it that warm amber Nixie glow, with laser etchings mimicking both the fine hexagonal anode grid and the ghostly cathodes of the non-illuminated numerals. The tubes looked convincing enough that a clock was in order, and after sorting through an I2C bottleneck with the help of a multiplexer, [Derek] had a pretty decent faux-Nixie clock, complete with a solenoid-actuated mechanical gong. The double-digit display for the seconds will no doubt cause some consternation among Nixie purists, but that’s probably part of the fun.

Of course, just because Nixies aren’t being mass-produced today doesn’t mean you can’t get new ones. You just have to be willing to pay for them, and [Dalibor Farný] will gladly set you up with his handmade artisanal Nixies, or even a clock kit using them.

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Flex PCBs Make Force-Mapping Pressure Sensor For Amputee

What prosthetic limbs can do these days is nothing short of miraculous, and can change the life of an amputee in so many ways. But no matter what advanced sensors and actuators are added to the prosthetic, it has to interface with the wearer’s body, and that can lead to problems.

Measuring and mapping the pressure on the residual limb is the business of this flexible force-sensing matrix. The idea for a two-dimensional force map came from one of [chris.coulson]’s classmates, an amputee who developed a single-channel pressure sensor to help him solve a painful fitting problem. [chris.coulson] was reminded of a piezoresistive yoga mat build from [Marco Reps], which we featured a while back, and figured a scaled-down version might be just the thing to map pressure points across the prosthetic interface. Rather than the expensive and tediously-applied web of copper tape [Marco] used, [chris] chose flexible PCBs to sandwich the Velostat piezoresistive material. An interface board multiplexes the 16 elements of the sensor array to a PIC which gathers and records testing data. [chris] even built a test stand with a solenoid to apply pressure to the sensor and test its frequency response to determine what sorts of measurements are possible.

We think the project is a great application for flex PCBs, and a perfect entry into our Flexible PCB Contest. You should enter too. Even though [chris] has a prototype, you don’t need one to enter: just an idea would do. Do something up on Fritzing, make a full EAGLE schematic, or just jot a block diagram down on a napkin. We want to see your ideas, and if it’s good enough you can win a flex PCB to get you started. What are you waiting for?

There Are 10 Kinds Of Computers In The World

There’s an old joke that there are 10 kinds of people in the world. Those who know binary, those who don’t, and those who didn’t see a base three joke coming. Perhaps [Dmitry Sokolov] heard that joke because he’s built a ternary (base 3) computer. He claims it is the first one to be built in the last 50 years. You can see a video about the device below. There’s also a video of the device with a nixie tube output.

You may not think of it often, but bit is a contraction of binary digit, so a ternary computer doesn’t have those. It has trits. The CPU operates on 3 trit words and uses nothing but multiplexers as building blocks. Instructions use 5 trits, some of which are a two-trit opcode and a 3 trit address of one of the 13 registers. The allure of using ternary, by the way, is that you can represent more numbers in fewer bits — um, trits, rather.

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Why Only Use One Controller When You Can Use ALL Of Them?

After booting up his RetroPie system, [jfrmilner] had the distinct feeling that something was off. Realizing that the modern Xbox 360 controller didn’t fit right when reliving the games of his youth, he rounded up all his old controllers to make sure he always had the right gamepad for the game.

Wanting to keep the controllers unmodified — so they could still be used on the original systems — he had to do a bit of reverse-engineering and source some controller sockets before building his controller hub. Using shift-in registers, shift-out registers, and some multiplexers, he designed a large circuit selector — which acts as a shield for an Arduino Micro — so all the controllers remain connected. A potentiometer allows him to select the desired controller and a few arcade buttons which access RetroPie shortcuts really round out the hub. Check out the demo after the break!

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A Few Of Our Favorite Chips: 4051 Analog Mux

Raindrops on roses, and whiskers on kittens? They’re alright, I suppose. But when it comes down to it, I’d probably rather have a bunch of 4051, 4052, and 4053 analog multiplexers on the component shelf. Why? Because the ability to switch analog signals around, routing them at will, under control of a microcontroller is tremendously powerful.

Whether you want to read a capacitive-sensing keyboard or just switch among audio signals, nothing beats a mux! Read on and see if you agree.

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Neopixels Light The Way In Pressure-Sensitive Floor

It’s got a little “Saturday Night Fever” vibe to it, but this pressure-sensitive LED floor was made for gaming, not for dancing.

Either way, [creed_bratton_]’s build looks pretty good. The floor is a 5×6 grid of thick HDPE cutting boards raised up on a 2×4 lumber frame. Each cell has a Neopixel ring and a single force-sensitive resistor to detect pressure on the pad. Two 16-channel multiplexers were needed to consolidate the inputs for the Arduino that’s running the show, and a whole bunch of wall warts power everything. The video below shows a little of the build and a look under the tiles. It’s not clear exactly what game this floor is for, but you can easily imagine a maze or some other puzzle that needs to be solved with footsteps.

Light-up floors are nothing new here, what with this swimming pool dance floor. But this interactive dance floor comes close to the gaming aspect of [creed_bratton_]’s build.

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