EDF Removes Hill Necessity For Snowboarding

Getting stuck on a flat portion of a trail while snowboarding is a major buzz kill. You can either hop yourself to the nearest slight downhill or unstrap your board and take a walk. Neither option is fun. [Jude] was tired of getting stuck on the flats so he strapped an electric ducted fan to the back of his snowboard.

The powerplant is an Electric Ducted Fan (EDF) intended for RC Aircraft. It is supported on the snowboard by a 3D printed mount. [Jude] made his mount design available for anyone interested in following his lead. Good ole glue holds the fan to the mount and the mount to the snowboard.

The battery is a 12S, which means it has 12 LiPo cells, 3.7 vdc each, wired in series to put out 44.4 volts. Inbetween the battery and brushless motor in the EDF is an Electronic Speed Control (ESC) that is normally used for RC vehicles. [Jude] purchased an ultra-cheap RC transmitter and receiver setup to give him one-handed wireless control of the fan’s speed. He estimates he can hit 15 mph on flat ground. If nothing else, it looks darn fun to ride!

Continue reading “EDF Removes Hill Necessity For Snowboarding”

Simple Superheterodyne SW Receiver Harks Back Almost 100 years

Early radio receivers worked on a principle called Tuned Radio frequency (TRF), patented in 1916. They weren’t very easy to use, requiring each stage to be tuned to the same frequency (until ganged capacitors made that a bit easy). The Superheterodyne design, devised in 1918, was superior, but more expensive at that time. Cost considerations led adoption of the Superhet design to lag behind TRF until almost 1930. Since then, until quite recently, the Superhet design has been at the heart of a majority of commercial radio receivers. Direct Conversion Receivers were devised around 1930, but required elaborate phase locked loops which restricted their use in commercial receivers. The point of all this background is that the Superhet design has served very well for more than 90 years, but will soon be rendered redundant once Software defined Radio (SDR) becomes ubiquitous. Which is why this study of the simple Superheterodyne shortwave receiver deserves closer study.

[Dilshan] built this two transistor and two IF transformer based superheterodyne radio designed to receive 13m to 41m bands. The whole build is assembled on a breadboard, making it easy to teach others to experiment. [Dilshan] offers very useful insights into antenna, rod coil and IF transformer parameters. To dive in to Radio architecture, check this post on Amateur Radio. And if you would like to get a closer look at Antique Radios, check this post on Restoring Antique Radios.

Non-Arduino powered by a piece of Computing history

Sometimes it is a blessing to have some spare time on your hands, specially if you are a hacker with lots of ideas and skill to bring them to life. [Matt] was lucky enough to have all of that and recently completed an ambitious project 8 months in the making – a Non-Arduino powered by the giant of computing history – Intel’s 8086 processor. Luckily, [Matt] provides a link to describe what Non-Arduino actually means; it’s a board that is shield-compatible, but not Arduino IDE compatible.

He was driven by a desire to build a single board computer in the old style, specifically, one with a traditional local bus. In the early days, a System Development Kit for Intel’s emerging range of  microprocessors would have involved a fair bit of discrete hardware, and software tools which were not all too easy to use.

Back in his den, [Matt] was grappling with his own set of challenges. The 8086 is a microprocessor, not a microcontroller like the AVR, so the software side of things are quite different. He quickly found himself locking horns with complex concepts such as assembly bootstrapping routines, linker scripts, code relocation, memory maps, vectors and so on. The hardware side of things was also difficult. But his goal was learning so he did not take any short cuts along the way.

[Matt] documented his project in detail, listing out the various microprocessors that run on his 8OD board, describing the software that makes it all run, linking to the schematics and source code. There’s also an interesting section on running Soviet era (USSR) microprocessor clones on the 8OD. He is still contemplating if it is worthwhile building this board in quantities, considering it uses some not so easy to source parts. If you are interested in contributing to the project, you could get lucky. [Matt] has a few spares of the prototypes which he is willing to loan out to anyone who can can convince him that they could add some value to the project.

Continue reading “Non-Arduino powered by a piece of Computing history”

Turning an Ordinary Pen into a Covert Radio Receiver

[Ben Krasnow’s] latest project will be good for anyone who wants a complicated way to cheat on a test. He’s managed to squeeze a tiny FM radio receiver into a ballpoint pen. He also built his own bone conduction microphone to make covert listening possible. The FM radio receiver is nothing too special. It’s just an off the shelf receiver that is small enough to fit into a fatter pen. The real trick is to figure out a way to listen to the radio in a way that others won’t notice. That’s where the bone conduction microphone comes in.

A normal speaker will vibrate, changing the air pressure around us. When those changes reach our ear drums, we hear sound. A bone conduction mic takes another approach. This type of microphone must be pressed up against a bone in your skull, in this case the teeth. The speaker then vibrates against the jaw and radiates up to the cochlea in the ear. The result is a speaker that is extremely quiet unless it is pressed against your face.

Building the bone conduction mic was pretty simple. [Ben] started with a typical disk-shaped piezoelectric transducer. These devices expand and contract when an alternating current is passed through them at a high enough voltage. He cut the disk into a rectangular shape so that it would fit inside of the clicker on the ballpoint pen. He then encased it in a cylinder of epoxy.

The transducer requires a much higher voltage audio signal than the litter radio normally puts out. To remedy this problem, [Ben] wired up a small impedance matching transformer to increase the voltage. With everything in place, all [Ben] has to do to listen to the radio is chew on the end of his pen. While this technology might help a cheater pass an exam, [Ben] also notes that a less nefarious use of this technology might be to place the speaker inside of the mouthpiece of a CamelBak. This would allow a hiker to listen to music without blocking out the surrounding noise. Continue reading “Turning an Ordinary Pen into a Covert Radio Receiver”

Wireless Helmet Speakers Receive A+ For Distracting Wearer

What could be better than cruising around town on your fave scooter? Cruising around town on your fave scooter listening to some cool tunes, of course! [sswanton] was enrolled in an Industrial Design course and was tasked with creating a wireless radio project for a specific user (of his choice). He decided to add some wireless speakers to a motorcycle helmet and design a handlebar-mounted radio.

Helmet Radio[sswanton] started out by disassembling the ultra-inexpensive, old-school, battery-powered Sony ICF-S22 radio specified by the class. The stock case was discarded as he would have to make a new one that fits onto the bike’s handlebars. Plywood makes up majority of the frame while the cover is black acrylic. Getting the acrylic bent required heating to 160 degrees so that it could be bent around a form [sswanton] created specifically for this project. A few cutouts in the case allows the rider to access the volume and tuning knobs.

The speakers added to the helmet were from wireless headphones and came with a matched transmitter. The transmitter was removed from it’s unnecessarily large case, installed in the radio’s newly created enclosure and connected to the radio’s headphone output. Situating the headphone components in the ideal locations of the helmet required that the headphones be disassembled. The speakers were placed in the helmets ear cups. Part of the original headphone case and some control buttons were mounted on the outside of the helmet for easy access. The wires connecting the components had to be extended to reconnect the now spread-out parts.

In order to hear that sweet music all the rider needs to do is turn on the headphones and radio. Check this out to see some more helmet speakers, this time a little more wacky.

Hackaday Links: December 21, 2014

Most of the incredible flight simulator enthusiasts with 737 cockpits in their garage are from the US. What happens when they’re from Slovenia? They built an A320 cockpit. The majority of the build comes from an old Cyprus Airways aircraft, with most of the work being wiring up the switches, lights, and figuring out how to display the simulated world out of the cockpit.

Google Cardboard is the $4 answer to the Oculus Rift – a cardboard box and smartphone you strap to your head. [Frooxius] missed being able to interact with objects in these 3D virtual worlds, so he came up with this thing. He adapted a symbol tracking library for AR, and is now able to hold an object in his hands while looking at a virtual object in 3D.

Heat your house with candles! Yes, it’s the latest Indiegogo campaign that can be debunked with 7th grade math. This “igloo for candles” will heat a room up by 2 or 3 degrees, or a little bit less than a person with an average metabolism will.

Last week, we saw a post that gave the Samsung NX300 the ability to lock the pictures taken by the camera with public key cryptography. [g3gg0] wrote in to tell us he did the same thing with a Canon EOS camera.

The guys at Flite Test put up a video that should be handy for RC enthusiasts and BattleBot contenders alike. They’re tricking out transmitters, putting push buttons where toggle switches should go, on/off switches where pots should go, and generally making a transmitter more useful. It’s also a useful repair guide.

[Frank Zhao] made a mineral oil aquarium and put a computer in it. i7, GTX 970, 16GB RAM, and a 480GB SSD. It’s a little bigger than most of the other aquarium computers we’ve seen thanks to the microATX mobo, and of course there are NeoPixels and a bubbly treasure chest.

Hackaday Links: December 14, 2014


The Progressive Snapshot is a small device that plugs into the ODB-II port on your car, figures out how terrible of a driver you are, and sends that data to Progressive servers so a discount (or increase) can be applied to your car insurance policy. [Jared] wondered what was inside this little device, so he did a teardown. There’s an Atmel ARM in there along with a SIM card. Anyone else want to have a go at reverse engineering this thing from a few pictures?

[Alex]’s dad received a special gift for his company’s 50th anniversary – a Zippo Ziplight. Basically, its a flashlight stuffed into the metal Zippo lighter we all know and love. The problem is, it’s battery-powered, and Zippo doesn’t make them any more. It also uses AAAA batteries. Yes, four As. No problem, because you can take apart a 9V and get six of them.

‘Tis the season to decorate things, I guess, and here’s a Hackaday snowflake. That’s from [Benjamin Gray], someone who really knows his way around a laser cutter.

HHaviing trouble wiith a debounce ciircut? HHer’s a calculator for just thhat problem. Put iin the logiic hhiigh voltage level, the bounce tiime, and the fiinal voltage, and you get the capaciitor value and resiistor value.

A harmonograph is a device that puts a pen on a pendulum, drawing out complex curves that even a spirograph would find impressive. [Matt] wanted to make some harmonographs, but a CNC and a printing press got in the way. He’s actually making some interesting prints that would be difficult if not impossible to make with a traditional harmonograph – [Matt] can control the depth and width of the cut, making for some interesting patterns.

The Mooltipass, the Developed On Hackaday offline password keeper, has had an interesting crowdfunding campaign and now it’s completely funded. The person who tipped it over was [Shad Van Den Hul]. Go him. There’s still two days left in the campaign, so now’s the time if you want one.