Prototyping a Maglev train using LEGO

lego-maglev

Serious research using not-so-serious equipment? We don’t know about that. What’s wrong with using LEGO as a research platform for a Maglev? This team has been doing so for quite some time and with great results.

A Maglev is a vehicle based on the principles of magnetic levitation. Similar poles of magnets repel each other and this concept can be used to create a friction-less track system. But this raises the problems of braking and locomotion. The build log linked above covers the conception in what is the eighth iteration of the research project. But the video below offers the most concise explanation of their approach to these issues.

The researchers are using magnets positioned in trench of the track as a kind of magnetic gear to push against. A series of electromagnets on the Lego vehicle ride in that track. The can be energized, working as a linear motor to push against those permanent magnets. But how do you know which direction of travel this will cause? That problem was solved by adding a hall effect sensor between each electromagnet. Before switching on the coil the hall effect sensors are polled and a timing scheme is selected based on their value. This is used to push the train up to speed, as well as slow it down for braking.

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LEGO jukebox choses from different CDs

lego-jukebox

Music used to be delivered on round plastic sheets called Compact Discs. [Ralph] still has some of them lying around which he used in his latest project. It’s a CD changer built out of LEGO pieces. It reminds us of the mid-century jukeboxes that changed out 45s on a record player.

You can’t tell from this image, but the entire disc changer build is shaped to sit atop a computer case. The system is built in two parts. There is a transport arm which moves left and right along the rack of CDs. It uses that black and white strip as an encoder to track its movement. It can reach in, grab a disc, and take it all the way down to the right where it drops it off in a staging area. The second part of the build now takes over, grabbing the disc from the staging holder and rotating it down into the CD tray of the PC. All of this is demonstrated after the jump.

If you’re like us you prefer digital delivery for your music. We haven’t crossed that watershed with video games yet and that’s why we still love this Xbox 360 disc changer hack.

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Hackaday Links: Sunday, April 21st, 2013

hackaday-links-chain

Regular reader and master hacker [Bill Porter] got married. Congratulations [Bill] and [Mara]! The two of them just couldn’t leave their soldering irons at home. The actually swore their vows by soldering together a circuit during the ceremony (blinky wedding dress, el wire tuxedo, and all).

[Kevin] sent in a link to [Red Fathom's] hacked Wacom tablet. It’s the screen from a Wacom-enabled laptop brought back to life with a Teensy and an LVDS interface module.

The Neato XV-11 is able to find its charging station when the batteries run low. [Derek] figured out that you can make a second station using some reflective tape.

If you use your drill a lot you’ll eventually break the rubber thing that holds the key to the chuck. Here’s a way to 3D print a replacement.

[Torxe] put eight floppy drives to use as a polyphonic Arduino-controlled MIDI player. And while we’re on the subject of Arduino controlled projects you should take a look at this web-interface to tell you if the foosball table is being used.

And finally [Th3 Bad Wolf] sent in this link to a milling machine built out of LEGO. It is able to mill floral foam and uses a lathe-like setup for one of the table axes.

Measuring the lifespan of LEGO

lifespan-of-LEGO

How many times can you put two LEGO pieces together and take them apart again before they wear out? The answer is 37,112. At least that’s the number established by one test case. [Phillipe Cantin] was interested in this peculiar question so he built the test rig above to measure a LEGO’s lifespan.

The hacked together apparatus is pretty ingenious. It uses two servo motors for testing, each driven by the Arduino which is logging the count on an SD card. One of the two white LEGO parts has been screwed onto an arm of the upper servo. That servo presses down onto the mating piece which is sitting inside that yellow band. Look close and you’ll realize the yellow is the handle end of an IC puller. When the post on the lower servo is moved toward one arm of the puller it grips the lower LEGO piece tightly so that the upper servo can pull the two apart. In addition to the assembly and disassembly step there’s a verification step which raises the mated parts so that a reflectance sensor can verify that they’re holding together. [Phillipe] let the rig run for ten days straight before the pieces failed.

Don’t miss his video description of the project after the break.

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LEGO stylus solves Ruzzle tablet game

mindstorm-ruzzle-solver

This grid of letters is a puzzle game for tablet devices called Ruzzle. The contraption attached is an automated solver which uses LEGO Mindstorm parts to input the solutions on the screen. [Alberto Sarullo] is the mastermind behind the project. As you can seen in his demo video after the break he has a flair for the cinematic. But he makes you work a little bit to discover the details of his project.

His post gives a general overview of how this works. A Linux box takes a screenshot of the Ruzzle board. After processing the graphics with Imagemagick he uses Tesseract — an Optical Character Recognition program — to figure out which letter is on each square of the playing area. From there NodeJS is used to discover all possible words with the help of a dictionary file. The final solutions are pushed to the LEGO parts to be traced out on the touch screen with a stylus. The nice thing is that he published all of his code, so you can drill much deeper into the project by pawing through his repository.

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LEGO LP Player

This LP player is made entirely out of LEGO parts. It plays the songs encoded on each record, but not by using a stylus in a groove. Instead, each LP has a color code on the bottom of it which is interpreted by the optical sensors underneath.

In addition to its functionality [Anika Vuurzoon] made sure that the build looked the part. The horn is a nice touch, but you’ll also appreciate the rotating mini-figures on the front side of the base. To the right there is a hidden door that provides access to the NXT brick which drives the system. New records are produced using a couple of different tools. First off, the song is written using Finale, a mature musical notation program. That is exported and run through a second program which produces the colored disc design which is applied to the records. You can hear the songs for yourself in the clip after the break.

If LP playing toys are right up your alley you’ll want to check out this 3D printed record hack for a Fisher Price toy.

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LEGO Record Player

Some people claim that the sound of vinyl is superior to digital playback. While this hack wont win any awards for audio quality, [Ryan]‘s LEGO Record Player is a unique use of one of our favorite toys. Most of the components including the tone arm, counterweight, and base, are built entirely of LEGO. A large gear from an educational construction set is used for the platter. Unfortunately, the rotation isn’t terribly smooth, and the playback is rather distorted.

The turntable uses a standard cartridge and stylus, which should allow it to be connected to any receiver with a phono preamplifier. Using these off the shelf parts, it’s possible to build the mechanical components a turntable out of a variety of things. As the video demonstrates, getting the platter to turn correctly is a bit of a challenge.

Check out a video of the wobbly playback featuring Cindy and Bert after the break.

Via Make

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