DIY USB Spectrometer Actually Works

image of diy spectrometer

When we hear spectrometer, we usually think of some piece of high-end test equipment sitting in a CSI lab. Sure, a hacker could make one if he or she put their mind to it. But make one out of a webcam, some cheap diffraction grating purchased off ebay and some scrap? Surely not.

[Renaud] pulls off this MacGyver like build with a detailed knowledge of how spectrometers work. A diffraction grating is used to split the incoming light into its component wavelengths. Much like a prism would. The wavelengths then make their way through a slit, which [Renaud] made from two pieces of highly polished brass, so the webcam sensor can see a specific wavelength. While the spectrometer-from-webcam concept isn’t new,  the build is still impressive.

Once the build was complete, [Renaud] put together some software to make sense of the data. Though a bit short on details, we hope this build will inspire you to make your own spectrometer, and document it on of course.

A Lesson in Blind Reverse Engineering – Signals Intelligence

spread sheet of binary data

In a fit of desperation, I turned to data mining tools and algorithms, but stepped back from the horror of that unspeakable knowledge before my mind was shattered. That way madness lies.

–[Rory O'hare]

Wise words. Wise words, indeed. Who among us hasn’t sat staring into the abyss of seemingly endless data without the slightest clue to what it means or even how to go about figuring out what it means? To literally feel the brain damage seeping in as you start to see ‘ones’ and ‘zeros’ reach out to you from every day electronic devices…like some ghost in the wires. But do not fear, wise hacker! For we have good news to report! [Rory O'hare] has dived into this very abyss, and has emerged successful.

While others were out and about playing games and doing whatever non-hackers do to entertain themselves, [Rory O'hare] decided to reach out and grab some random wireless signals for a little fun and excitement. And what he found was not just a strong, repeating signal at 433Mhz. Not just a signal that oozed with evidence of ASK. What he found was a challenge…a mystery that was begging to be solved. A way to test his skill set. Could he reverse engineer a signal by just looking at the signal alone? Read on, and find out.




Smart Hat Puts Your Head in the Game

man wearing a diy head mounted display


[Arvind] has dropped his hat in the game of head mounted displays. With Google Glass pushing $1,500, it’s only natural for hackers to make a cheaper alternative. [Avind's] $80 version might not be pretty, but it gets the job done.

Using a Raspberry Pi loaded with speech recognition software, a webcam, 2.5 inch LCD display and a handful of other parts, [Arvind's] hat mounted display allows him to view email, Google Maps, videos or just about anything he wants.

An aspheric loupe magnifier lens lets him see the display even though it sits around 5cm from his eye. No outside light is allowed in. Only the guts of the webcam were used to give him the video and microphone. We’ve seen other head mounted displays before, and this one adds to the growing collection. Be sure to check out [Arvinds] site for a tutorial on how to build your own, and catch a video of it in action after the break.

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THP Entry: Atomic Space Time

LCD featuring HaD logo

Accurate time is all around us. Streaming down from satellites thousands of miles in space, UTC time information is at all of our fingertips. You just have to know how to reach out and grab it. [hkdcsf] not only knows how to do this, he does it in style.

Tipping his hat into The Hackaday Prize contest, [hkdcsf]‘s atomic clock is masterfully crafted. Not only does it get time information from GPS satellites, it also has the ability to grab the infomation from the DCF77 transmitter. And if ever it’s in a position where neither signal can be found, an RTC crystal keeps the time and date accurate.

His design is based on a PIC18F25K20, and bristles with so many features that it might make you dizzy. So be warned – you might want to be in a seated position before taking a look at this project. [hkdcsf] does a great job at detailing exactly how his clock works, and his efforts to provide this level of detail will surely help other hackers to add similar features to their future projects.

SpaceWrencherThe project featured in this post is an entry in The Hackaday Prize. Build something awesome and win a trip to space or hundreds of other prizes.

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ADC For Raspi Without Using An ADC

Schematic of ACD for a raspi

With all the amazing and wonderful things a Raspberry Pi can do, it is sorely lacking a dedicated ADC chip. Sure, you can wire up an ADC via SPI or even I2C with a little work, but still. It would be nice to have access to an Analog to Digital converter without having to go through the trouble. Fortunately, [Hussam] has figured out a way to do just this.

Using a comparator, two resistors, a single capacitor and a few lines of code, [Hussam] managed to get an active ADC working on his Raspberry Pi. He’s using the PWM1 and a passive RC filter to make a DAC. He then uses the comparator along with a ‘ successive approximation algorithm’ to complete the ADC.

[Hussam] mentions that the hack is not new, and this technique has been used before for microcrotrollers that lack a built-in ADC. But we are still impressed with his attention to detail in describing how to do this on a Raspi. Be sure to check out the link for full details, code, and an awesome description on how his algorithm works.

Vintage Radio Rocks With Modern Technology

old soviet transistor radio

[Madis] had an old Soviet Russian Neywa 402 transistor radio sitting on the shelf. It looked cool, but unfortunately that’s about all it did. Built in the 70’s one can only wonder about the past life of the radio. And one can only wonder what the past owner thought about the future of it, if they thought about it at all? Would they have thought that several decades in the future, a hardware hacker would introduce some strange and mysterious technology to breath new life into it? Probably not. But that’s exactly what happened.

[Madis] picked up a Bluetooth speaker from Ebay for a whopping $10. And like any good hacker, he immediately took it apart and ditched the original speaker. Wired up to the vintage radio, the Bluetooth receiver can be charged via a USB cable, which neatly tucks away in the back of the case. And with a few taps of his smart phone, he can stream audio to his new vintage Bluetooth speaker.

Though a simple hack, [Madis] does a great job at breathing new life into an antique electronic device. Check out the video after the break for a demonstration.

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Ask Hackaday: Global Energy Transmission – Can It Work?

global transmission logo with earth in the background

Atop a small mountain in Colorado Springs sat the small, makeshift laboratory of Nikola Tesla. He chose this location because the air was thinner, and therefor more conductive. Tesla had come to believe that he could use the Earth as a conductor, and use it to send electrical power without the need for wires. Though some facts are forever lost, it is said that on a clear, moonless night, Tesla flipped the switch that fed millions of volts into a large coil that towered high into the air. He cackled maniacally as an eerie blue corona formed around the crackling instruments, while some 200 florescent bulbs began to glow over 25 miles away.

A magnificent feat took place in the hills of Colorado that night. A feat that surely would change the world in how it harnessed electricity. A feat that if brought to its full potential, could provide wireless power to every point on the globe. A feat that took place almost one hundred and twenty years ago…


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