The Cassette MP3 Player

1994 was twenty years ago. There are people eligible to vote who vaguely remember only one Bush presidency. You can have a conversation with someone born after the millennium, and they think a 3.5 inch disk is called a save icon. Starting to feel old? Don’t worry, all the trinkets of your youth have now become shells for MP3 players, the cassette tape included.

[Britt] is aware you can pick up one of these cassette tape MP3 players through the usual channels, but she wanted her build to be a little different. She’s using ar real, vintage cassette tape for starters, and from the outside, looks pretty much like any other cassette tape: there’s a thin strip of tape at the bottom, and the clear plastic window shows the tape is at the beginning of side A.

Outside appearances are just that; inside, there is a small, repurposed MP3 player, with tact switches wired up to the old buttons, actuated by moving the spools back and forth. Yes, you actually play, pause, rewind and fast forward by sticking a pencil in the spool and moving it back and forth. Amazing.

It’s a great build, and considering both cassette tapes and cheap MP3 players can be found in the trash these days, it’s something that should be hard to replicate.

Toddler Jukebox Requires No Quarters or Button Mashing

Ahh, toddlers. They’re as ham-fisted as they are curious. It’s difficult to have to say no when they want to touch and engage with the things that we love and want them to play with. [Shawn] feels this way about his son’s interest in the family Sonos system and engineered an elegant solution he calls Song Blocks.

The Sonos sits on a dresser that hides a RasPi B+. Using bare walnut blocks numbered 1-12, his son can use the Sonos without actually touching it. Each block has a magnet and an NFC tag. When his son sticks a block on the face of the right drawer containing embedded magnets and an NFC controller board, the B+ reads the tag and plays the song. It also tweets the song selection and artist.

The blocks themselves are quite beautiful. [Shawn] numbered them with what look like Courier New stamps and then burned the numbers in with a soldering iron. His Python script is on the git, and he has links to the libraries used on his build page. The Song Blocks demo video is waiting for you after the jump.

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The Triple Delta Robot Arm (and Leg)

delta By now you’d think we’ve seen just about every means of robotic actuator possible. We have Cartesian bots, Stewart platforms, SCARA bots, Delta bots, and even some exceedingly bizarre linkages from [Nicholas Seward]. We’re not done with odd robotic arms, it seems, and now we have Delta-ish robots that can move outside their minimum enclosed volume. They’re fresh from the workshop of [Aad van der Geest], and he’s calling them double and triple Deltas.

Previous Delta robots have used three universal joints to move the end effector up and down, and side to side. They’re extremely fast and are a great design for 3D printers and pick and place machines, but they do have a limitation: the tip of a single Delta can not move much further than the base of the robot.

By adding more parallelograms to a Delta, [Aad] greatly increases working volume of a his robots. One of the suggested uses for this style of bot is for palletizers, demonstrated in the video below by stacking Jenga blocks. There is another very interesting application: legs. There’s footage of a small, simple triple Delta scooting around the floor, supported by wire training wheels below. It makes a good cat toy, but we’d love to see a bipedal robot with this style of legs.

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Paper Plane Folding Machine Gun is a Mechanical Marvel

A German man has just finished a very impressive Paper Airplane Machine Gun, or a Papierflieger-Maschinenpistole, which just sounds so much cooler. It actually takes a stack of paper, folds it into paper air planes and shoots them.

The device takes a stack of what looks like post-card size paper in the “clip”, forms them into paper air planes by a series of rollers and folding edges and then launches them out of the end. A cheap electric screwdriver powers the entire drive train, which allows him to shoot around 20 planes per minute (PPM?).

Sadly there’s really not too much information on how it works, nor the files to reproduce it. [Papierfliegerei], as he goes by on YouTube, decided to build this awesome contraption to show off just what 3D printers are capable of these days. He designed the whole thing in 3D CAD and had many of the parts printed off at a 3D printing company called, while the rest of the components are off the shelf.

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Hackaday 10th Anniversary: Hacking Your Way To NASA

[Steve] drives spacecraft for a living. As an engineer at the Jet Propulsion Laboratory, he’s guided probes to comets, asteroids, Mars, and Jupiter, figured out what happens when telemetry from these probes starts looking weird, and fills the role of the Space Hippy whenever NASA needs some unofficial PR.

Like most people who are impossibly cool, [Steve]’s career isn’t something he actively pursued since childhood. Rather, it’s something that fell in his lap. With qualifications like building a robotic computer to typewriter interface, a custom in-car navigation system in the late 80s, and a lot of work with an Amiga, we can see where [Steve] got his skills.

The earliest ‘hack’ [Steve] can remember was just that – an ugly, poorly welded sidecar for his bicycle made in his early teens. From there, he graduated to Lasertag landmines, Tesla coils, and building camera rigs, including a little bit of work on Octopussy, and a rig for a Miata. It helps when your dad is a cinematographer, it seems.

In college, [Steve] used his experience with 6502 assembler to create one of the first computerized lighting controllers (pre-DMX). After reading a biography on [Buzz Aldrin], [Steve] realized doing his thesis on orbital rendezvous would at least be interesting, if not an exceptionally good way to get the attention of NASA.

Around this time, [Steve] ran into an engineering firm that was developing, ‘something like Mathematica’ for the Apple II, and knowing 6502 assembly got him in the door. This company was also working to get the GPS constellation up and running, and [Steve]’s thesis on orbital mechanics eventually got him a job at JPL.

There’s several lifetimes worth of hacks and builds [Steve] went over at the end of his talk. The highlights include a C64 navigation system for a VW bug, a water drop high voltage machine, and a video editing system built from a few optical encoders. This experience with hacking and modding has served him well at work, too: when the star sensor for Deep Space 1 failed, [Steve] and his coworkers used the science camera as a stand in navigation aid.

One final note: Yes, I asked [Steve] if he played Kerbal Space Program. He’s heard of it, but hasn’t spent much time in it. He was impressed with it, though, and we’ll get a video of him flying around the Jool system eventually.

Fail of the Week: Transparent Circuit Design is Clearly a Challenge

[Frank Zhao] wanted to try his hand at making a transparent circuit board. His plan was to etch the paths with a laser cutter and fill in the troughs with conductive ink. The grooves are ~0.1mm deep x ~0.8mm wide.

He used nickel ink, which is slightly cheaper than silver ink. The ink was among the least of his problems, though. At a measured resistance of several hundred ohms per inch, it was already a deal breaker since his circuit can’t function with a voltage drop above 0.3V. To make matters worse, the valleys are rough due to the motion of the laser cutter and don’t play well with the push-to-dispense nature of the pen’s tip. This caused some overflow that he couldn’t deal with elegantly since the ink also happens to melt acrylic.

[Frank] is going to have another go at it with copper foil and wider tracks. Do you think he would have fared better with silver ink and a different delivery method, like a transfer pipette? How about deeper grooves?

2013-09-05-Hackaday-Fail-tips-tileFail of the Week is a Hackaday column which runs every Thursday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

Delta Coffee-Brewing Bot

Pour-over coffee brewing is a simple and cheap hands-on alternative to using an automatic coffee maker. Although coffee aficionados often choose pour-over just for the manual brewing experience, this didn’t stop [Elias] from automating his pour-over coffee setup with an elaborate delta-robot: the DeBrew.

The coffee-brewing robot is built around a delta assembly from a 3d printer controlled by a BeagleBone Black. The BeagleBone drives stepper motors, displays information on a small open-source hardware HDMI LCD display, and serves up a web interface to control the machine. The radius of the pouring pattern, water temperature, and grind coarseness of the DeBrew can all be customized though its web interface.

For those who want to build their own pour-over robot, [Elias] has made a SketchUp drawing of the design and all of his Python source code available as open-source. Check out the video after the break where [Elias] explains how his delta pour-over bot works.

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