Laser-Cut Clock Uses Planetary Gear

[wyojustin] was trying to think of projects he could do that would take advantage of some of the fabrication tech that’s become available to the average hobbyist. Even though he doesn’t have any particular interest in clocks, [wyojustin] discovered that he could learn a lot about the tools he has access to by building a clock.

[wyojustin] first made a clock based off of a design by [Brian Wagner] that we featured a while back. The clock uses an idler wheel to move the hour ring so it doesn’t need a separate hour hand. After he built his first design, [wyojustin] realized he could add a planetary gear that could move an hour hand as well. After a bit of trial and error with gear ratios, he landed on a design that worked.

The clock’s movement is a stepper motor that’s driven by an Arduino. Although [wyojustin] isn’t too happy with the appearance of his electronics, the drive setup seems to work pretty well. Check out [wyojustin]’s site to see the other clock builds he’s done (including a version with a second hand), and you can peruse all of his design files on GitHub.

Looking for more clock-building inspiration? Check out some other awesome clock builds we’ve featured before.

An Upgrade To A Raspberry Pi Media Server

For the last few years, [Luke] has been running a music server with a Raspberry Pi. With the new Raspberry Pi 2 and its quad core processor, he thought it was time for an upgrade.

The build consists of a Raspi 2, a HiFiBerry Dac to address the complaints of terrible audio on the Pi, an aluminum enclosure, and some electronics for IO and a real software shutdown for the Pi. The Arduino also handles an IR remote and a rotary encoder on the front of the enclosure.

The software is the Logitech Media Server along with Squeezeslave. The front end is custom, though, with functions for shutdown and receiving IR remote codes. Everything is served up by Flask, with a 32GB microSD card stuffed into the Pi to store MP3s. All in all, a great build.

Low-Voltage Tesla Coil Uses a Relay Instead of a Spark Gap

[Teodor] writes in with a unique Tesla coil he designed and built. Unlike most Tesla coils, [Teodor]’s design is able to run with a fairly low input voltage because it doesn’t use a static spark gap like most Tesla coils. Instead, his coil uses a relay in place of a spark gap.

[Teodor] built his coil using leftover components from his old school, making good use of some parts that might have otherwise been thrown away. The most critical component of his circuit, the relay, is just a standard normally-closed relay that is rated at 20A. [Teodor] wired the relay so that it energizes its own coil whenever it is shut. This causes the relay to briefly open every time the coil is energized, creating a resonant circuit. The resonant circuit charges a tank capacitor and places it in series with the primary coil inductor every time the relay closes, forming the tank circuit of his design.

With [Teodor]’s design, the resonant frequency of the secondary is nearly identical to that of the primary. This creates a significant voltage boost, helping produce very high voltages from such a low input voltage. The only downside to this design that [Teodor] recently discovered is that the relay contacts get red-hot after a few minutes of operation. Not optimal, but it still works! Check out [Teodor]’s writeup for more details and instructions on how to build your own.

Hackaday Links: March 1, 2015

The somewhat regular Hardware Developers Didactic Galactic was a few days ago in San Francisco. Here’s the video to prove it. Highlights include [James Whong] from Moooshimeter, the two-input multimeter, [Mark Garrison] from Saleae, and a half-dozen other people giving talks on how to develop hardware.

[Taylor] made a portable NES with a retron, a new-ish NES clone that somehow fits entirely in a glop top IC. The controllers sucked, but [Taylor] made a new one with touch sensors. All that was required was eight transistors. The enclosure is an Altoid tin, and everything works great.

Here’s a YouTube channel you should subscribe to: Ham College. The latest episode covers the history of radio receivers and a crystal radio demonstration. They’re also going through some of the Technical class question pool, providing the answers and justification for those answers.

[Prusa] just relaunched prusaprinters and he’s churning out new content for it. Up now is an interview with [Rick Nidata] and his awesome printed container ship.

The tip line is overflowing with ESP8266 breakout boards. Here’s the simplest one of them all. It’s a breadboard adapter with stickers on the pin headers. Turn that into a right-angle breadboard adapter, and you’ll really have something.

Here’s something that’s a bit old, but still great. [Dillon Markey], one of the stop-motion animators for Robot Chicken modified a Nintendo Power Glove for animation duties. It seems to work great, despite being so bad. Thanks [Nicholas] for the link.

[David] the Swede – a consummate remote control professional we’ve seen a few times before – just flew his tricopter in a mall so dead it has its own Wikipedia page. Awesome tricopter, awesome location, awesome video, although we have to wonder how a few really, really bright LEDs would make this video look.

Here’s an item from the tip line. [Mark] wrote in with an email, “Why do you put names in [square brackets] in the blog entries? Just curious.” The official, [Caleb]-era answer to that question is that sometimes people have bizarre names that just don’t work in text. Imagine the sentence, “[12VDC] connected the wires to the terminal” without brackets. The semi-official answer I give is, “because.”

Automated Pocky Dispenser

Sometimes, along comes a build project that is not so much a fail, as how not to do it. First off, some of us here had to look up what a Pocky is, never having heard, seen or tasted one – seriously. Once satisfied, we turned our attention to [Michael]’s Automated Pocky Dispenser. Took a while for us to figure out if it’s useful or not. But it’s a fun, quick project that [Michael] put together in around an hour using parts lying around in his office.

For those of you who’d like to know, a Pocky is a chocolate-coated biscuit stick, although you can also buy it in other flavors. You can grab one from a box, but maybe it tastes better when you dispense it by banging a big red button. [Michael] says he used  incredibly advanced construction techniques, but we leave it to our readers to decide on that. The key element of the build is the special “flexible coupling” that he built to transfer the rotation of the stepper motor to the dispensing mechanism. The rest of the build consists of an Arduino, stepper motor, driver, and giant red button. Special motor driving code ensures that the dispenser wiggles back and forth every time, preventing any stuck Pocky’s. And the Electronics are, well, hanging out for all to see. Happy with the success of his build, [Michael] is planning an upgraded version – to connect the Pocky Dispenser to the cloud for statistical gathering of office Pocky habits. He claims even Google does not have that data. To see the dispenser in action, check out the video below.

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Retro Edition: VCF East, April 17 – 19

Around this time last year we were planning our trip to the Vintage Computer Festival East in Wall, NJ. This year we’re doing it all over again, and according to the announcements coming out of the planning committee, it’s going to be a very, very cool event.

This year marks fifty years since the release of the PDP-8, regarded as the first commercially successful computer ever. The historic Straight-8 from the infamous RESISTORS has been restored over the past few months, and it’s going to be turned on again for the festival. There will also be a half a dozen other PDP-8s at the event, but these are 8/M, 8/E, and 8/L models and not constructed completely out of discrete diode transistor logic.

Keynote speakers include [Wesley Clark], designer of the LINC computer and [Bob Frankston], co-creator of Visicalc. There will, of course, be a ton of educational and historical sessions on Friday. Our own [Bil Herd] will be there talking about vintage microcomputer architectures along with a dozen other fascinating people talking about really interesting stuff

As far as exhibits go, there’s literally everything you could imagine when it comes to retro computers. There will of course be a fully restored and functional PDP Straight 8, along with PDP-11s, Apple Newtons, Ataris, Network gaming on C64s. Hollerith cards, VisiCalc, mainframes, teletypes, video toasters, an RTTY amateur radio station (KC1CKV), a flea market/consignment thing, and all sorts of retro goodies. Oh, a Fairlight CMI will also be there. I don’t know how they got that one.

More info for VCF East at the official site, Facebook, and Twitter. If you’re in the area and want to exhibit something really, really cool, there’s still room for more. If you want a better feel for what will be going down at VCF East, check out our megapost wrapup from last year.

Of course if New Jersey isn’t your thing and you live a few blocks down from Peachtree Avenue, Lane, or Street, VCF Southeast 3.0 will be held in Roswell, Georgia the first weekend in May.

Reverse Engineering Wireless Temperature Probes

[bhunting] lives right up against the Rockies, and for a while he’s wanted to measure the temperature variations against the inside of his house against the temperature swings outside. The sensible way to do this would be to put a few wireless temperature-logging probes around the house, and log all that data with a computer. A temperature sensor, microcontroller, wireless module, battery, case, and miscellaneous parts meant each node in the sensor grid would cost about $10. The other day, [bhunting] came across the exact same thing in the clearance bin of Walmart – $10 for a wireless temperature sensor, and the only thing he would have to do is reverse engineer the protocol.

These wireless temperature sensors are exactly what you would expect for a cheap piece of Chinese electronics found in the clearance bin at Walmart. There’s a small radio operating at 433MHz, a temperature sensor, and a microcontroller under a blob of epoxy. The microcontroller and transmitter board in the temperature sensor were only attached by a ribbon cable, and each of the lines were labeled. After finding power and ground, [bhunting] took a scope to the wires that provided the data to the radio and took a look at it with a logic analyzer.

After a bit of work, [bhunting] was able to figure out how the temperature sensor sent data back to the base station, and with a bit of surgery to one of these base stations, he had a way to read the temperature data with an Arduino. From there, it’s just a data logging problem that’s easily solved with Excel, and [bhunting] has exactly what he originally wanted, thanks to a find in the Walmart clearance bin.