Split Flap Display: If You Can’t Find It, Built It

October 4, 2014 by Mike Szczys 18 Comments

It’s pretty hard to deny that split-flap displays are incredibly awesome. This one has been a long time coming, and it’s not a refab or surplus build. [Tom] fabricated these beautiful alpha-numeric split flaps from scratch.

Having recently seen an alarm-clock split flap hack just a week or so ago we found ourselves wondering where in the world people manage to find this type of awesome mechanical hardware. If you can’t get it out of grampa’s attic, the next best thing is to build it from the ground up.

This was not a build to be taken lightly. [Tom] started years ago, and part way into the project we looked at some of the control hardware for the installation. Make sure that you dig deep into his blog posts. It’s the only way you’ll put together the whole picture of how he ended up with each belt and stepper motor driven character module.

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Sine Waves, Squares Waves, And The Occasional FFT

October 1, 2014 by Bil Herd 35 Comments

I became aware of harmonics and the sound of different shaped waveforms early in my electronics career (mid 1970’s) as I was an avid fan of [Emerson Lake and Palmer], [Pink Floyd], [Yes], and the list goes on. I knew every note of [Karn Evil 9] and could hear the sweeping filters and the fundamental wave shapes underneath it.

I remember coming to the understanding that a square wave, which is a collection of fundamental and (odd) harmonics frequencies, could then be used to give an indication of frequency response. If the high frequencies were missing the sharp edges of the square wave would round off. The opposite was then true, if the low frequencies were missing the square wave couldn’t “hold” its value and the top plateau would start to sag.

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A Nixie Clock With Neon Bulb Logic

September 29, 2014 by Brian Benchoff 27 Comments

This is an oldie, but oh, man is this ever good. It’s a Nixie clock made without a microcontroller. In fact, there aren’t any logic chips in this circuit, either. As far as we can tell, the logic in this clock is made with resistors, diodes, caps, and neon tubes.

The design of this is covered in the creator’s webpage. This clock was inspired by a few circuits found in a 1967 book Electronic Counting Circuits by J.B. Dance. The theory of these circuits rely on the different voltages required to light a neon lamp (the striking voltage) versus the voltage required to stay lit (the maintaining voltage). If you’re exceptionally clever with some diodes and resistors, you can create a counting circuit with these lamps, and since it’s pretty easy to get the mains frequency, a neon logic clock starts looking like a relatively easy project.

This clock, like a lot of the author’s other work, is built dead bug style, and everything looks phenomenal. It looks like this clock is mounted to a plastic plate; a good thing, because something of this size would be very, very fragile.

Video below, thanks [jp] for sending this one in.

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The LPT DAC

September 29, 2014 by Brian Benchoff 41 Comments

About 30 years ago, before every computer had CD quality audio built in, audio cards and chips were technological marvels. MIDI chips, FM synthesis, and synths on a chip reigned supreme but one little device – just a handful of resistors – sounded fantastic. it was the Covox Speech Thing, a simple resistor ladder wired up to the parallel port of a computer that would output 8-bit audio to an external amplifier. [FK] recently built his own Covox (Czech, Google translatrix) with just 18 resistors, and the results sound fantastic.

Instead of fancy chips, the original Covox Speech Thing used the 8 bit parallel port on a PC. Back in the olden days, this was the fastest way to get digital data out of a computer, but since it was digital only, a DAC was required to turn this into audio. A simple resistor ladder was sufficient, and this hardware was eventually supported by the old DOS games from Sierra and Id.

[FK] has a demo of this LPT DAC available here, but we’re not thinking that link will last long. If anyone has a better link, leave a note in the comments and we’ll update this post. Thanks [beavel] for sending this in.

Bring A Hack At World Maker Faire 2014

September 26, 2014 by Adam Fabio 3 Comments

After a hard Saturday at World Maker Faire, some of the best and brightest in the Hacker/Maker community descended on The Holiday Inn for “Bring A Hack”. Created by [Jeri Ellsworth] several years ago at the Bay Area Maker Faire, Bring A Hack (BAH) is an informal gathering. Sometimes a dinner, sometimes a group getting together at a local bar, BAH is has just one rule: You have to bring a hack!

[Sophi Kravitz] has become the unofficial event organizer for BAH in New York. This year she did a bit of live hacking, as she converted her Wobble Wonder headgear from wired to wireless control.

[Chris Gammell] brought his original Bench BudEE from Contextual Electronics. He showed off a few of his board customizations, including making a TSSOP part fit on the wrong footprint.

[Windell and Lenore] from Evil Mad Scientist Laboratories brought a few hacks along. They picked up an old Radio Shack music player chip at the Electronics Flea Market and built it up on a breadboard. Also on display was their new EggBot Pro. The Pro is a beautifully machined version of the eggbot. Everything is built strong to withstand the sort of duty an EggBot would see at a hackerspace or public library. [Windell] was full of surprises, as he also gave everyone chunks of Sal Ammoniac, which is a great way to bring the tin back to a tired soldering iron tip. The hack was that he found his Sal Ammoniac at a local Indian grocery in the Bay Area. Check out [Windell’s] blog entry for more information.

[Cal Howard] brought his DIY VR goggles. [Cal] converted a Kindle Fire into an Oculus Rift style head mounted display by adding a couple of magnifying lenses, some bamboo kebab sticks to hold the lenses in place. Judicious use of cardboard and duct tape completed the project. His current hurdle is getting past the Fire’s lack of an accelerometer. [Cal] planned to spend Sunday at Maker Faire adding one of his own!

As the hour grew late, everyone started to trickle out. Tired but happy from a long day at Maker Faire, the Bring A Hacker partygoers headed back to their hotels to get some sleep before World Maker Faire’s final day.

Low-Level Computing With Entry-Level Difficulty: DUO Light

September 20, 2014 by Mike Szczys 27 Comments

The hardware can’t get much simpler. The DUO Light uses an ATmega328 (commonly found on Arduino boards) along with an external SRAM chip to provide a low-level computer programming experience that will suit those new to programming and some more experienced tinkerers.

At the time of writing the modest Kickstarter goal of $1100 was just $18 shy of success. We’d wager that this is partly due to the availability of so much support material on [Jack’s] website. (fyi- a lot of the links on that page are zip files)

The SD card slot accepts a FAT16 card with byte code for the programs. The available Psuedo C compiler, and assembler let you pick your poison, or you can simply dig into the byte code directly. We didn’t see a schematic, but the firmware and BOM are both available. You should be able to easily figure out connections from those.

We’ve been a fan of [Jack’s] work for quite some time. His TTL computer and 16-core ATmega-based offerings are sure to delight, even if you remember seeing them go by the first time. This isn’t his first stab at educational models either. Though we still found his logic chip computer a bit daunting.

Stepping Through Code On A Pace 4000 Set Top Box

September 19, 2014 by Mike Szczys 14 Comments

[Lee] wrote in to tell us about a Set Top Box he hacked. Before the cable industry lawyers get out their flaming swords… he’s not stealing cable, or really doing much of anything. This is a hack just for the adventure and thrill of making someone else’s hardware design do your bidding without any kind of instructions.

He posted about the adventure in two parts. The first is finding the JTAG header and identifying the pins. Arduino to the rescue! No really, and this is the type of Arduino use we love. Using a package called JTAGenum the board becomes a quick tool for probing and identifying JTAG connections.

The image above shows a different piece of hardware. From looking at it we’re pretty sure this is a Bus Blaster which is specifically designed for JTAG debugging with ARM processors. This is the beginning of the second part of his documentation which involves code dumping and stepping through lines code (or instructions) using OpenOCD and GDB. It’s a chore to follow all that [Lee] discovered just to write his name to the display of the box. But we certainly found it interesting. The display has a convoluted addressing scheme. We assume that there are cascading shift registers driving the segments and that’s why it behaves the way it does. Take a look for yourself and let us know what you think in the comments.