Year: 2011

Hackaday Links: December 11, 2011

December 11, 2011 by 23 Comments

Drilling square holes

We’re still a bit baffled by the physics of this, but apparently it’s possible to drill a square hole with a round bit. This video shows square holes being milled using a cutter which is offset from the center of the bit. [Thanks Jordan]

LED Motorcycle headlight driven by mains

[William] found a way to use a big capacitor and bridge rectifier to run this H4 LED headlight bulb in a mains sconce lamp.

Electronic slide whistle

Here’s an electronic instrument that [Dorian] made. It uses a linear potentiometer and a button and works much like a slide whistle would.

Robot rocks out to Daft Punk

[Adrian] didn’t just make a robot arm out of CD cases and a mints tin. He built the arm, then made a music video featuring it.

More light-pipe sensor experiments

[Uwe] has been working on an input sensor using a flexible light tube. It is a similar idea to these optical flex sensors, but [Uwe] tried several variations like filling the tube with alcohol.

A Little Fire Breathing Pony To Call Your Own

December 10, 2011 by 13 Comments

[Lvl_joe] has been having a little fun with fire and an animatronic pony. The skeletal horse seen above is a child’s toy denuded of its original plush shell. That’s a good thing, because those synthetic fibers don’t play very nicely with flames. The toy originally retailed for around $300 bucks, but if you’re lucky, like [Joe], you can get one second-hand for $25 or less.

Since the horse is already motorized, it’s not too hard to patch into the drivers. Here an Arduino is used to take input from a Wii Nunchuck, letting you swing the fire sprayer to and fro. A grill igniter makes sure it’s not just spraying automotive starter fluid everywhere. You can hear the click of that tiny spark repeatedly firing in the demo video after the break. The starter fluid comes in an aerosol can. A custom trigger system holds the can in a PVC pipe, and actuates the valve with a Bowden cable.

Continue reading “A Little Fire Breathing Pony To Call Your Own” →

Nine Not-so-easy Steps To Build A Singing Tesla Coil

December 10, 2011 by 7 Comments

We love a good Tesla coil music performance, but have never really considered building our own. After reading [TheHomebrewGuru’s] guide to musical Tesla coils we’re still not considering it. Whether or not you’re going to undertake the project, his massive writeup is worth a look.

The tutorial begins at the beginning, with a bit of background on these devices, including what they are, where they came from, and the electrical theory behind them. From there it’s on to the build. This isn’t a go-out-and-buy it type of project. You’re going to need some ingenuity to hunt down parts that will work, and will work with each other.

The image above shows a partially built device, using sheet metal ductwork covered in foil tape as the torroid at the top. The column is wrapped in wire, forming the secondary coil, and the wooden base is ready for the installation of the primary coil. Electronics will be housed between the two wood discs of the base, with a TI Launchpad board driving the music part of the hack.

There isn’t a good demo video of this playing music. But you can get the idea if you look back at the head-mounted tesla coil which did a great job of pumping out the tunes.

[Ian] Shops Akihabara

December 10, 2011 by 32 Comments

Hackaday alum and Dangerous Prototypes founder [Ian Lesnet] is in Japan and he’s been spending a lot of time at Akihabara Electric Town. For those that don’t recognize the name, this is an electronic components extravaganza with buildings packed full of small shops each specializing in different merchandise. For instance, we love this picture of a shop that carries every kind of protoboard, breakout board, and copper clad sheet imaginable. The stall next door might have nothing but LEDs, or be full of cords for every purpose.

We’ve been following [Ian’s] regular tweets about the trip. Luckily, he just posted a roundup of the Akihabara posts. Surprisingly, he restrained himself to purchasing just a few items. Part of this is a limit on the amount of stuff he can get back to the States with him. The other reason is that the prices are not necessarily less than you’d find in a catalog. He mentions that the nice thing is you can see the parts before buying them. This is useful for sizing knobs, transformers, cases, etc.

The most exciting thing in his bag is a half-dozen nixie-like VFD tubes for just $12. How much would you give to have this shopping attraction down the street from you?

If you’re interested in a video tour of Akihabara check out this one from the Tokyo Hackerspace.

[via @dangerousproto]

Weekly Roundup 12/10/11

December 10, 2011 by No comments


In case you missed them the first time, here are our most popular posts from the past week.

In first place is a post that made our mothers’ wash our mouths out with soap. It is a periodic table of swearing!

Up next is a post about a micromouse robot that can run a maze faster than you would think is possible. Watch out lab rats, it’s gunning for your job.

Are regular violins too low tech? Would you rather play an instrument that could survive a few minutes with Chuck Norris and still keep playing the sweetest melodies? [Ken] created a violin out of carbon fiber that fits the bill.

Want to brake some aluminum? (or bend for the white collar folks out there.) In this post, you can see [Rupert’s] build where he has created a metal brake out of little more than bamboo and some hinges.

Last but not the least is [Zach’s] build that changes the brightness of his Christmas tree lights based on the pitch of the notes from the Star Wars theme.

R/C Blimp Uses A Party Balloon For Lift

December 9, 2011 by 21 Comments

Here’s a really tiny r/c blimp that doesn’t need several cubic feet of Helium to get off the ground.

Instructables user [masynmachien] has been building r/c blimps for over a decade now, and this latest build is meant to have the same specs as this nanoblimp. The build is based on an 11-inch party balloon that can provide about 11 grams of lift. This doesn’t allow for much leeway in terms of weight, so [masymachien] used hacked-up servos for the motors.

The blimp is an exercise in saving weight – just about every component that can be removed from the build is thrown away. The results are pretty impressive. The entire blimp weighs about 10 grams on the ground. [masynmachien] also tried a 14-inch balloon with an 808 key fob camera with very good results.

The blimp looks pretty good when flying around a room. [masymachien] seems to have a lot of control from a minimal component count. You can check out the party blimp in action after the break.

Continue reading “R/C Blimp Uses A Party Balloon For Lift” →

Simulating PenTile RGBG Displays

December 9, 2011 by 22 Comments

Here’s an interesting experiment that lets you simulate PenTile displays on a normal LCD monitor. [Barrett Blackwood] wanted to test out how some graphics look on PenTile RGBG displays with different pixel densities. These PenTile RGBG matrices are sometimes used in OLED displays. For instance, the Nexus One smart phone features a display of this type. Because red, green, and blue OLEDs emit different intensities of light, the pixels are laid out differently from LCD panels in order to balance the color mixing. Our eyes see the green light very well, and so green sub-pixels are made much smaller than their red and blue counterparts.

Because the hardware layout is different, some graphics appear to have crosshatching artifacts in them when viewed on the PenTile displays. [Barrett] made the example above to simulate how graphics look on a traditional LCD screen (image on the left), and how they appear on the PenTile scren (image on the right). The magenta hue seen above is a result of resizing the image. Since the simulation method turns off 1/3 of the green pixels in the image, resizing it ruins the careful calculation. It must be view at a 1:1 ratio to see the image correctly, at which point the magenta magically disappears.