Highway Based Soundtrack Recordings

September 1, 2011 by Brian Benchoff 21 Comments

[Urpo Lankinen] has a father who is a huge movie buff, and once you care deeply about something it begins appearing everywhere you look. While driving on a back-country road one day, [Urpo]’s dad noticed that the shadows of the trees on the road looked like an optical film soundtrack, so it was up to the son to make it happen.

Early sound-on-film technologies like the RCA Photophone, and Movietone recorded audio onto the film stock with a variable area exposure. This exposure corresponds to the waveform of the audio signal. [Urpo] figured that his small digital video camera served the same purpose as the audio sensors inside the projector, so he put a piece of tissue paper over the lens and wound up with a video that was just frames of gray.

[Urpo] built an app in Processing that averages the pixels in each frame of the video. Of course, recording at 30 frames/second won’t produce any audio this way, so he modulated a triangle wave with this data in Audacity. In the end it really doesn’t sound like much, but it’s great to see such a geeky build.

We’d love to post the video after a break but [Urpo] doesn’t believe in YouTube embeds. We’ll honor his wishes, so you can check out the video here.

Zigbee Home Automation Gives Us Another Reason Not To Get Up

August 24, 2011 by Brian Benchoff 27 Comments

[Russell] sent in a neat home automation project he’s been working on. Even though the project only has two devices so far, we can already see the potential of his project.

Instead of the X10 standard that has been a staple of home automation for more than 30 years, [Russell] went with ZigBee modules. Aside from being much faster and more flexible than X10 home automation modules, ZigBees also open up a bunch of projects that would be impossible if he went with X10. With some well-placed IR transmitters hidden in his living room, it would be possible to have a TV and cable box controlled via the Internet.

So far, [Russell] built an network-controlled RGB ‘mood lamp’ and an infrared remote for his central air. Everything is controlled through a web app, and [Russell] says that additional modules can be easily added to the code.

Check out [Russell]’s demo of his project after the break.

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Ohm Sense Makes Sense Of Resistor Color Bands

August 6, 2011 by Brian Benchoff 59 Comments

[Alex Busman]’s first foray in iOS programming looks like a pretty useful tool. He came up with Ohm Sense, an iPhone app that will take a picture of a resistor and calculate the value based on the color bands. It’s a great tool that we wish we had when we were starting out. At 99 cents, the app is also much cheaper than the emotional cost of our relationship with Violet.

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Building A One-instruction Computer

July 27, 2011 by Brian Benchoff 23 Comments

[Hasith] sent in this project where he goes through the process of designing a one instruction CPU in Verilog. It may not win a contest for the coolest build on Hack A Day, but we really do appreciate the “applied nerd” aspect of this build.

With only one instruction, an OISC is a lot simpler than the mess we have to deal with today. There are a few instructions that by themselves are Turing-complete (like Subtract and branch if negative, and Move). Designing an OISC with one of these instructions means it can also emulate a Turing machine.

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A Study In AVR Power Saving Techniques

July 26, 2011 by Mike Nathan 88 Comments

amtel_avr

[Scott] found the iCufflinks from Adafruit Industries pretty interesting, but he thought that the stated run time of 24 hours was a bit short. He figured he could improve the product’s power consumption at least a little bit, to improve the overall battery life.

From their schematics, he placed an order for parts and built two identical iCufflink mock-ups side by side – one running their code and one running his. He took baseline current draw measurements, then got busy slimming down the cufflinks’ software. It had been 20 years since he touched assembly, and he has never written it for an AVR, but judging by his work he’s not rusty in the least.

He slowed the ATtiny’s clock down and tweaked a few other settings for a savings of 53μA, but the real improvements came via a fairly simple fix. The original code called for the processor to institute a counting loop to sleep, which he found to be very wasteful. Instead, he chose to put the processor in an idle state, using the chip’s watchdog timer to wake it when it was time to pulse the LED. The power savings from this change alone was a whopping 261μA!

When he was said and done, the changes save about 315μA of current draw, and should allow the cufflinks to run for up to 38 hours without swapping batteries. In [Scott’s] opinion, a nearly 60% improvement in battery life is pretty good for a day’s work, and we’re inclined to agree.

Zzstructure Emulator

July 12, 2011 by Brian Benchoff 14 Comments

[John Ohno] has been working on a zzstructure operating system written C since January. [John] realizes not many people know what a zzstructure is, so he posted a demo of his project. [John] has also put all the code online.

A zzstructure is both a hypertext and operating system unlike anything we have today. You could say that when it was first conceived in 1960 it was 100 years ahead of its time. [John]’s implementation of zzstructures operates on a 256-dimension grid and functions a lot like a multidimensional forum thread. Although that’s a lot to wrap your head around, it can probably best be explained by [Ted Nelson], the creator of zzstructures.

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Voice Recognition System Controls Everything, Hopefully Won’t Kill Us.

July 8, 2011 by Brian Benchoff 8 Comments

[Aaron Bitler] and [Bud Townsend] have been working a natural user system that is, in their own words, “what android@home should have been.”

The video they posted is pretty impressive. The automation system responds to voice and can control appliances, ‘throw a party’, and provide a user with their location. This is just the foundation of a system that can be built upon – developers can easily integrate a microphone and speaker into a device so it can connect to the system’s server. Apps, too, are pretty extensible – they’re registered on the server with meta tags that provide a wealth of data to be manipulated. It’s a very, very cool project that we really want to try out.

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