PIC Spectrum Analyzer Uses Fast Fourier Transform Routine

[Simon Inns] just rolled out his latest project, a PIC based spectrum analyzer. He’s using a Fast Fourier Transform routine crafted in C to run as efficiently as possible on the 8-bit chip. The video after the break shows that the results are quite pleasing, with just a bit of noticeable lag between the sound and the waveform representation on the graphic LCD. We found his notes about using an audio amplifier chip to be interesting. He utilizes the properties of an LM386 to move the input signals from a range of -0.5V to +0.5V into a very ADC friendly range of 0-5V.

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Make The Wedding Ring Speak To Her

It’s a nice touch to engrave a heartfelt message on a wedding band, and my couples choose to do so. But you can say a lot more with a 20 second audio message. That’s exactly what [Luke Jerram] did by etching an audio track into this ring. He uses his custom-built hardware to playback the message, which you can see in the video after the break. The ring is an Edison Cylinder, which works just like a modern record player except that the media is on a spinning drum (the ring) instead of a rotating disk. We wonder if this would sound a bit better with a high-end cylinder player.

While you’re on [Luke’s] page you might as well take a look at his image projecting ring as well. It has a color image slide on one side and a projection lens on the other. Wacky!

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Fabricating A Music-controlled Stoplight

[Andrew] built himself a stoplight that flashes along with the music. Unlike the traffic signal we checked in on a year ago, this one’s not a reused municipal fixture. [Andrew] imported a 3D model into Sketchup, printed out the results, and traced them onto Bristol board to make his templates. He cut out the parts, used a brake for the bending, then a combination of spot and MIG welding to complete the housing. Off to his school’s spray booth for priming, baking, and painting for a perfect finish.

The internals are what you’d expect. Each light source is made up of a cluster of LEDs controlled by an Arduino. Music synchronization is handled by a Processing script that [Andrew] wrote, which you can see in action after the break.

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Tape Delay Made From Recycled Cassette Decks

Professional tape delay units are great fun, but often expensive. You’d think that with so many derelict cassette decks filling the world’s dumpsters someone must have figured out a way to make a cheap tape delay… not only in the interest of saving money (sometimes quality is worth paying for) but also in the interest of re-using otherwise wasted resources.

Forosdeelectronica forum user [Dano] has made just such a device from used cassette decks and miscellaneous parts (translated). First he investigated the operation of the playback, erase, and record mechanisms and broke out the tape heads. The playback head is on a plastic rail so that the delay time can be changed, while the record head is fixed. [Dano] encountered some difficulties in ensuring good quality for the recording and erasure, which is an important consideration when working with magnetic tape.

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If You’re Photographing And You Know It Clap Your Hands

If you’ve ever tried to take pictures of yourself you’ll know that it can be a pain. It’s especially hard to get that perfect shot of your godly features when you’re out of breath from sprinting across the room. OK, yes, they have remote controls for that. But what if you lost your remote or you just don’t want to have to carry it? [LucidScience] put together a sweet, um, “hands free” alternative.

Essentially this hack emulates the IR signals sent by a Nikon remote, either to take a picture right away or to take time lapse photographs at regular intervals. We’ve seen a similar time lapse remote using an arduino before and a really thorough one using an AVR, but they don’t take the same approach as [LucidScience]’s design in terms of monitoring a microphone input for triggering. The project includes several status LEDs and adjustments for ambient noise and triggering, and it can be mounted to the camera body. We wonder how many of the Nikon’s features could be controlled using clap encoding, and how detailed your timing would need to be to have a kind of hand-made (get it?) pulsetrain syntax.  You’d probably need to have world record clap skills.

Check out the demo vid after the break.

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Rich Decibel’s Kequencer

It’s totally excellent when a simple concept results in something inspiring and fun. [Rich Decibel]’s Kequencer is a good example, starting off as many projects do: “I had an idea the other day and I couldn’t decide if it was good or not so I just built it to find out.” Be still our hackable hearts!

[Rich] built this sleek little sequencer from scratch and while the design may not seem very novel to begin with–eight square wave oscillators with on/off switches and pitch knobs, played in sequence–but the beauty of it is in the nuances of interaction and the potential for further hacking. From watching the video you can see how the controls can be used in very interesting ways to create and mutate adorable chippy tone patterns. Check it out after the crossfade.

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MP3 Player Barely Larger Than An SD Card

If your board fabrication and soldering skills are up to it, you can make your own tiny MP3 player. This rendition is just about half again as large as a standard SD card, whose slot is on the bottom of the board seen above. The heavy lifting is taken care of by a VS1011 MP3 decoder which also has its own stereo headphone driver on-chip. There’s no display and it seems that most of the 4k of program memory on the PIC 18LF88 is being used. Too bad, we’d love to take this to the next level, attaching it to the head unit in a car and spoofing the communications as if this were a CD changer.

[via Hacked Gadgets]