This pass through audio modulator lets you playback stereo audio on two Tesla coils. But don’t fret, you can just use mono files if you only have one coil on hand. On one side there are inputs that connect to the audio source. The other side drives the Tesla coil, switching it on and off based on the relationship between a reference voltage and the audio signal. As you can hear in the video after the break this sounds great as long as you have the right kind of source audio.
The song played in that clip is the Duke Nukem 3D theme. [Daniel] started with a MIDI file and removed the chimes and drums to make the playback a little cleaner. The demo uses just one coil because the other was destroyed during testing when feedback between the two became a problem.
For some reason this reminds us of that singing Tesla coil hat. If you’re already on our mailing list (sign up in the sidebar) you know we’re getting pretty close to unveiling our own awesome Tesla coil project. It doesn’t sing… yet.
Filed under: misc hacks
Being real, ultimate geeks, [Bill] and [Mara] didn’t want to settle for plain, paper-based wedding invitations. No, they wanted something cooler, and came up with their own DIY electronic wedding invitations.
Since they would be making the invitations themselves, [Bill] and [Mara] needed a simple circuit that could be easily mass produced. They turned to the classic microcontroller-powered blinking LED circuit powered by an ATtiny13.
The first order of business was producing 50 printed circuit boards for each of the invitations. For this, [Bill] picked up an Xerox Phaser laser printer off of ebay and a few sheets of copper-clad kapton film. The etch resist was printed directly onto the kapton film and etched in a bath of ferric chloride, effectively making a flexible PCB.
These circuit boards were soldered up and laminated between the printed invitation and the card stock cutter with the help of a Silhouette Cameo paper cutter. After the cards were assembled, the battery was wired up and the cards shipped out.
The microcontroller inside the card was programmed to be asleep most of the time, waking up only every few seconds to check a light sensor to determine if the card was opened or not. If the microcontroller sensed the card was open, the lights began blinking, making it one of the most memorable wedding invitations [Bill] and [Mara]‘s guests will ever receive.
You can check out a demo of the invitations after the break.
Filed under: led hacks
We’ve seen computers built in Minecraft out of redstone, the game’s version of electricity, circuits, and digital logic. We’ve even seen a few redstone contraptions controlling real-world devices. [Angus]‘ build, though, takes things to a whole new level. He’s created a bridge between Minecraft circuits and their real life counterparts using a Raspberry Pi.
[Angus]‘ build relies on a mod for Minecraft servers running as a Bukkit plugin. Blocks powered by redstone are labeled with an in-game sign, and messages regarding the state of a block are passed over the network using the MQTT protocol.
The hardware side of the build is a Raspberry Pi with a PiFace expansion board. With this setup, [Angus] can control LEDs on the PiFace by toggling Minecraft levers, or light up redstone lamps using the PiFace’s buttons.
If you’d like to try this out for yourself, you can grab the Bukkit plugin over on [Angus]‘s git. Check out the video of the real life redstone in action after the break.
Filed under: Raspberry Pi
Not being a coffee drinker [Hunter Scott] wanted a way to make tea while lurking in his workshop. Well it’s not exactly rocket science, as all you need is water at the right temperature and a vessel in which the tea can be steeped. But we do commend him on not only building a nice little hot plate enclosure, but rolling a magnetic stirrer into the other side of the box.
You heard us right, the stirrer is not combined with the plate, but resides on the underside of the same PSU enclosure. The plate itself is from a unit he bought at the store and cannibalized. The light switch dimmer lets him adjust the heat it puts out. When not hot, he can flip it over and use the stir plate. This consists of a hard drive magnet attached to a PC fan. For the stirrer itself he encased a neodymium magnet in some thermoplastic. The magnetic combination works well together with a demonstration which shows it stirring water through the base of a tea-cup.
Filed under: chemistry hacks
For a theatre production, [Jason] needed a way to automatically open and close doors as a special effect. His solution, hosted on Github, lets him remotely control the doors, and put them into a ‘freak out’ mode for one scene in the play.
Two Victor 884 motor controllers are attached to an Arduino that controls the system. A custom controller lets [Jason] actuate the doors remotely, and LEDs are used to display the state of the system.
On the mechanical side, two wind shield wiper motors are used. These are connected to custom arms that were printed using a Lulzbot AO-100. The arms allow for the door to be automatically actuated, but also allow for actors to open the door manually.
The result is a neat special effect, and the 3D models that are included in the repository could be useful for other people looking to build automated doors. In the video after the break, [Jason] walks us through the system’s design and demonstrates it in action.
Filed under: robots hacks
The prices for custom made circuit boards has never been cheaper, but surprisingly we’ve never seen a comparison of prices between the major board houses. [Brad] took the time to dig in to the price of 10 boards manufactured by Seeed Studios, OHS Park, and BatchPCB. He made some pretty graphs and also answered the question of where you can get your circuits made cheaply.
For boards over 20 cm2, the cheapest option is Seeed Studios. In fact, the price difference between Seeed and the other board houses for the maximum sized board is impressive; a 400 cm2 board from Seeed costs $150, while the same board from OSH Park is close to $1000.
Of course most boards are much smaller, so the bottom line is for boards less than 20 cm2, your best bet is to go with OHS Park. If you don’t care when your boards arrive, or you need more than 10 or so, Seeed is the way to go. As far as the quality of the boards go, OSH Park is up there at the top as well.
Filed under: hardware
[Lee] wrote in to share the work he’s done in building a controller for his soldering iron. The idea started when he was working with an ATX power supply. He figured if it works as a makeshift bench supply perhaps he could use it as the source for an adjustable iron. To get around the built-in short-circuit protection he needed a potentiometer to limit the current while allowing for adjustments. His first circuit used a resistor salvaged from an AT supply and a trimpot from some computer speakers. That melted rather quickly as the pot was not power rated.
This is a picture of his next attempt. He built his own potentiometer. It uses the center conductor from some coaxial cable wrapped around the plastic frame of an old cooling fan. Once the wire was in place he sanded down the insulation on top to expose the conductor. The sweeper is a piece of solid core wire which pivots to connect to the coil in different places. It works, and so far he’s managed to adjust a 5V rail between 5A and 20A.
How would you make this system more robust? Short of buying a trimpot with a higher power rating, do you think this is the easy way to build a soldering iron controller? Let us know by leaving your thoughts in the comments.
Filed under: Ask Hackaday
When you’ve got a month worth of blog postings it’s pretty difficult to choose one photograph that sums it all up. This one shows the tour group from MIT Media Lab in ESD garb ready for their tour of Okano SMT and Speaker Factory. It was part of a tour of Shenzhen aimed at bringing graduate students up to speed on what it means to manufacture products in the city. Luckily, Freaklabs member [Akiba] was one of the staff members of the program and blogged extensively about the experience. At first glance his page full of post abstracts looks really boring, but click through because both his recount and the commented images associated with each day are fun and fascinating ways to tag along with the group.
If you’re really good with faces you can pick [Bunnie Huang] out of the lineup above (he’s the third from the right). He had the original idea for the program and brought aboard a few others to help make the thing a success. The group toured a wide range of factories and parts markets in the city. This included your traditional electronics manufacturing venues but there was even a side trip to a diaper and feminine napkin plant to see the non-electronic factories in operation. In addition to tours there were lectures by industry members like HAXLR8R, a group that specializes in helping start-ups navigate the manufacturing jungle.
Filed under: misc hacks
MEGA is a new, encrypted cloud storage system founded by [Kim Dotcom] of MegaUpload fame. They’re selling privacy in that the company won’t have the means to decrypt the data stored by users of its service. As with any software project, their developers are rapidly making improvements to the user interface and secure underpinnings. But it’s fun when we get some insight about possible security problems. It sounds like the issue [Marcan] wrote about has been fixed, but we still had a great time reading his post.
Filed under: security hacks
Get a little more exposure than one under-saddle bike light can provide by building your own LED enabled messenger bag. It looks like the bag itself was fabricated from scratch by [Andrew Maxwell-Parish] rather than altering an existing bag. He had a few goals for the project, the most interesting of which was to make the electronics removable. His reasoning for this is so he can get the bag past security at the airport.
The design is quite simple, there’s a large flap which is attached at the top of the bag and has a couple of clips at the bottom to keep ti closed. On the inside of the flap he sewed a snap system which holds one piece of material on which all of the electronics are attached. The Lilypad system is used (it looks like the original hardware and not the FLORA upgrade). The main unit is sewn to one side, while the Charlieplex LED matrix was attached in a grid centered on the flap. The lights shine through the orange fabric, keeping them fairly safe from the weather and giving them a reddish hue.
If you’re looking for a few more features check out this GPS enabled messenger bag.
Filed under: led hacks, wearable hacks