Retrotechtacular: The Spirit Of Radio

May 5, 2015 by 11 Comments

Many of us still tune in to terrestrial radio for one reason or another, be it baseball games, talk radio, or classic rock. But do you know how the sound is transmitted to your receiver? This week, our spotlight shines upon a short film produced by KYW Radio that serves as a cheerful introduction to the mysteries of amplitude modulation (AM) radio transmission as they were in 1940.

Sound vibrations enter a microphone and are converted to electrical current, or an audio waveform. The wave is amplified and sent several miles away to the transmitting station. During this trip, the signal loses power and so is amplified at the transmitting station in several stages. This audio wave can’t be transmitted by itself, though; it needs to catch a ride on a high-frequency carrier wave. This wave is generated on-site with a huge crystal oscillator, then subjected to its own series of amplifications prior to broadcast.

The final step is the amplitude modulation itself. Here, the changing amplitude of the original audio wave is used to modulate that of the high-frequency carrier wave. Now the signal is ready to be sent to the tower. Any receiver tuned in to the carrier frequency and in range of the signal will capture the carrier wave. Within the reciever, these currents are converted back to the vibrations that our ears know and love.

Continue reading “Retrotechtacular: The Spirit Of Radio” →

[Kenji Larsen] Shows Off The Ultimate Hacking Kit

May 5, 2015 by 40 Comments

If you roll into a hardware hackathon empty-handed, you’re going to be at a disadvantage compared to those who bring equipment with which they’re already familiar. Pray that you never roll into one where [Kenji Larsen] is your competitor. Luckily, this weekend he came out to mentor for Hackaday’s hardware hacking village at the TechCrunch Disrupt hackathon and not as a competitor. In this video he shows off the huge rollerbag which he calls his “Hack Pack”. I’d say there’s a 50/50 chance his travel setup is better than your home lab.

Where do I begin (seriously, watch the video)? Perhaps best to note is how organized he is. For instance, the large plastic bag containing his battery-operated and plug-in Dremels also has conveniently sized stock like acrylic and metal. There are compartment boxes full of sensors, others contain things like passives, batteries, battery chargers, hundreds of Moteino modules, handfuls of BeagleBones Black, breakout and dev boards of every flavor. He has all the necessary tools like hemostat, x-acto blade, steel ruler, and magnifying glasses. There’s even a 3D printer in the bag — a Printrbot Simple which [Chris Gammell] played with all weekend err… learned to use as part of his role as a mentor.

We had a ton of hardware along with us, but time and again [Kenji] was there for the save on some of the less-common needs. He’s a expert when it comes to fabrication techniques and it showed. We also give him mad points for staying up overnight for all 20-hours of the build session. Thank you so much [Kenji], I think I speak for every one of the hardware hackers when I say you helped bring the event to the next level of exhilarating and exhausting fun. Please direct your own thanks, stories, and well-wishes, and follows to [Kenji’s] hacker profile.

If you weren’t able to make it to NYC this weekend, you definitely missed out. We’ll be telling the story of that all week. Those on the West Coast will have a chance next weekend at Hackaday Prize Worldwide: LA. The workshop is sold out but socializing on Saturday, and a Sunday free-build are both still available for RSVPs.

Open Source, DIY Soldering Robot

May 5, 2015 by 85 Comments

After [Brian] starting selling his own Raspberry Pi expansion boards, he found himself with a need for a robot that could solder 40-pin headers for him. He first did what most people might do by looking up pre-built solutions. Unfortunately everything he found was either too slow, too big, or cost as much as a new car. That’s when he decided to just build his own soldering robot.

The robot looks similar to many 3D printer designs we’ve seen in the past, with several adjustments. The PCBs get mounted to a flat piece of aluminum dubbed the “PCB caddy”. The PCBs are mounted with custom-made pins that thread into the caddy. Once the PCBs are in place, they are clamped down with another small piece of aluminum. A computer slowly moves the caddy in one direction, moving the header’s pins along the path of the soldering irons one row at a time.

The machine has two soldering irons attached, allowing for two pins to be soldered simultaneously. The irons are retracted as the PCB caddy slides into place. They irons are then lowered onto the pins to apply heat. Two extruders then push the perfect amount of solder onto each pin. The solder melts upon contact with the hot pins, just as it would when soldered by hand.

The system was originally designed to be run on a Windows 8.1 tablet computer, but [Brian] found that the system’s internal battery would not charge while also acting like a USB host. Instead, they are running the Windows WPF application on full PC. All of the software and CAD files can be found on [Brian’s] github page. Also be sure to check out the demo video below. Continue reading “Open Source, DIY Soldering Robot” →

Trademarking Makerspace

May 5, 2015 by 89 Comments

UnternehmerTUMMakerSpaceGmbH, a tech accelerator in Munich, Germany, has just filed an application to trademark the word Makerspace. This has caused some contention in the German-speaking hackosphere, and if this trademark application is approved, the few spaces in Germany that identify as a makerspace may soon be changing the sign out front.

It must be noted this trademark application only covers the word ‘Makerspace’, and not “Hackerspace”. To most of the population, the word ‘hacker’ – in English and German – conjures up images of someone wearing a balaclava and using a laptop to steal bank accounts. To the uninitiated public, a hackerspace is distinct from a makerspace. In reality, they are remarkably similar: a hackerspace has a room filled with tools; a makerspace has a room filled with tools that allow people to control their language. Little difference, really, if you discount the [Frank Luntz]-level wordsmithing.

While this could go badly for any ~space in Germany with a ‘maker’ prefix, trademarking ‘makerspace’ isn’t really that much different from calling it a TechShop, and the trademark application is probably just a product of lawyers. In any event, it looks like  UnternehmerTUM MakerSpace GmbH has a pretty cool space; 1500m² (16000sq ft) of space, a water jet, and even some sewing equipment. We’d be happy to take a tour, so long as they don’t enforce the trademark.

Thanks [Moritz] for the tip.

Bicycle-Powered Wimshurst Machine

May 4, 2015 by 16 Comments

A lot of great pieces of real technology were inspired (or, at least, look like) pieces of technology from science fiction of the past. Like the smartphones of today have a surreal resemblance to the Star Trek communicators of the 60s, [Steve] took inspiration from a story about a bicycle racing in space and set out to make his own.

In the story, the bicycle wheels are replaced by electrostatic generators that power a type of (fictional) ion drive. Since an ion drive wouldn’t add much thrust to a bicycle operated on the Earth, [Steve] used the electrostatic generator he built to create a sparking light show. The generator is called a Wimshurst machine and has two counter-rotating discs which collect charge. The charge is dissipated across a spark gap which is placed where the bike light would normally go.

We don’t know if the sparks from the Wimshurst generator are enough for a proper headlight, but it’s definitely a cool effect. [Steve] also points out that it might also work as a bug zapper, but either way you should check out the video after the break to see it in action! While it’s not quite a tricorder it’s still a pretty impressive sci-fi-inspired build, and something that’s definitely unique in the bicycle realm.

There’s quite a collection of these Wimshurst projects beginning to come together. Here’s one made using a trio of soda bottles, and another example which used 3D printing.

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Polar Coordinate Mapping And RGB LED Disks

May 4, 2015 by 12 Comments

Last week, Adafruit released the DotStar RGB LED Disk, a 240mm diameter disk packed with 255 individually addressable RGB LEDs. Because blinkey glowey projects are the best projects, [Adam] had to have one. His tests open up some interesting possibilities in the world of blinkey LED stuff, including a polar coordinate display that would be perfect for low-res games and LED clocks.

[Adam] found the Disk sufficiently bright and glowey, but there were two problems. The first was the JST SM connector on the input of the DotStar Disk; with 255 LEDs on the disk, it has a maximum draw of over 10A, while the connector can only supply 7A without getting unreasonably warm. Secondly, there aren’t 60 LEDs around the outer edge of the disk, limiting its application as a clock.

There’s another thing wrong with the DotStar Disk, until you realize it’s effectively a polar coordinate display. RGB LED libraries are usually written for strips or matrices, not circles. The LEDs are sequentially arranged on the DotStar disk spiraling inwards, and after mucking about with some terrible code, [Adam] realized he could control a pixel with only its distance from center and angle from the connector. This makes plotting circles easier, but it also opens this display up to some interesting applications; circular Pong would be cool, and LED clocks are the bees knees.

Hackaday Prize Entry: A Low Cost, Open Source MRI

May 4, 2015 by 58 Comments

This low cost magnetic resonance imager isn’t [Peter]’s first attempt at medical imaging, and it isn’t his first project for the Hackaday Prize, either. He’s already built a CT scanner using a barium check source and a CCD marketed as a high-energy particle detector. His Hackaday Prize entry last year, an Open Source Science Tricorder with enough sensors to make [Spock] jealous, ended up winning fourth place.

[Peter]’s MRI scanner addresses some of the shortcomings of his Open Source CT scanner. While the CT scanner worked, it was exceptionally slow, taking hours to image a bell pepper. This was mostly due to the sensitivity of his particle detector and how hot a check source he could obtain. Unlike highly radioactive elements, you can just make high strength magnetic fields, making this MRI scanner potentially much more useful than a CT scanner.

There are a few things that make a low-cost MRI machine possible, the first being a way to visualize magnetic fields. For this, [Peter] is using an array of Honeywell HMC5883L 3-axis magnetometers, the smallest sensors he could find with the largest range. These magnetometers are I2C devices, so with a few multiplexers it’s actually a relatively simple build.

Imaging with these magnetometers is not simple, and it’s going to take a lot of work to make a signal from all the noise this magnetic camera will see. The technique [Peter] will use isn’t that much different from another 2014 Hackaday Prize entry, A Proton Precession Magnetometer. When a proton in your body is exposed to a high strength magnetic field, it will orient towards the high strength field. When the large field is turned off, the proton will orient itself towards the next strongest magnetic field, in this case, the Earth. As a proton orients itself to the Earth’s magnetic field, it oscillates very slightly, and this decaying oscillation is what the magnetic camera actually detects.

With some techniques from one of [Peter]’s publication, these oscillations can be turned into images. It won’t have the same resolution as an MRI machine that fills an entire room, but it will work. Imagine, an MRI device that will sit on a desktop, made out of laser-cut plywood. You can’t have a cooler project than that.

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