Aud-I/O I2S audio breakout

Bertho is working on a breakout board for the WM8782 I2S ADC and the WM8523 I2S DAC. The boards are intended to be interfaced with an ARM micro-controller.

I am working on a project that requires some real audio and I always wanted to play with I2S (attached to an arm microcontroller). So I decided to design a breakout board with stereo audio input and output(*). It uses a Wolfson ADC WM8782 and a Wolfson DAC WM8523. All configuration pins are available on the SIL headers. The headers are at 2x10x100mil with 700mil spacing, so it should be possible to dump it into a breadboard. The breakout board can be split into a DAC and ADC part, each measuring 21.6mm by 45.1mm.

Check out the project in the forum.

Global Geek Tour India: protoCentral shop tour

protoCentral is another open source hardware design studio we visited in Bangalore. They started out doing work for India’s military, building sensors and wireless gear. After using open hardware for some years himself, Ashwin decided to start distributing open hardware from SparkFun, Seeed Studio, and Arduino a few months ago. They are just now branching out into their own products.

Their primary aim is to create new hardware such as open source tools for students and engineers. They find that the current hardware is too expensive. and out of reach of students. They’d like to create an open source chemical sensor within the price range students.

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Global Geek Tour India: Tenet Technetronics tour

In Bangalore we had a chance to visit Tenet Technetronics, an open source hardware designer and distributor. Cool thing about their office is that it’s entirely built by the development team. They designed and fabricated all the furniture and installations in their office.

Tenent Technetroncis is selling open hardware like crazy, next year they hope to sell 35,000 boards. They distribute most big open hardware brands like Beagle Board, Arduino, and Raspberry Pie throughout India. As they celebrate their fifth anniversary, they look forward to opening offices around India and in the United States.

Work continues day, night, and weekends in the common office space. Tenent has hardware, firmware, software, and mechanical engineers turning out new designs.

Like many distributors we talked to, import duties imposed on hardware are strong incentive to manufacture boards locally. They currently sell in-house versions of locally manufactured open hardware projects like Arduino and IOIO.

They demoed a quad-copter intended for areal photography. It was stable enough to fly in a crowded office, or maybe those were just Dilip’s excellent piloting skills.

Tenent is doing a lot with high-end open hardware. We saw a bunch of demos using different single board Linux computers like the Raspberry Pi.

We thank Tenet Technetronics for welcoming us!

Beginners project: Arduino zombie detector


Yeah we know Halloween is over, but what better time for the zombie invasion to begin than when you let your guard down? With this easy Arduino project from MAKE, even beginners can be protected. Simply breadboard a PIR sensor, LED and buzzer and connect them to your Arduino. Then upload the code to your board to detect motion from the PIR and activate the LED and buzzer. This is a fun way for newbies to learn about digital IO and protect against the zombie apocalypse at the same time!

Code and instructions can be found on the MAKE project page.

Via MAKE.

Bus Pirate LCD Adapter free PCB build

Marv shared his free Bus Pirate LCD Adapter v2b build. This board lets your Bus Pirate drive HF44780 comparable LCDs.

If you build a free PCB we’ll send you another one! Blog about it, post a picture on Flicker, whatever – we’ll send you a coupon code for the free PCB drawer.

Grab an assembled Bus Pirate LCD adapter v3  for $9 at Seeed!

Via the forum.

App note: Detecting human falls with 3-axis accelerometers

Here is an article from Analog Devices discussing the theory and application of detecting human falls with 3-axis accelerometers. While the article focuses on the ADXL345 3-axis accelerometers, the theory and principle behind it can be applied to other devices as well.

This article, based on research into the principles of fall detection for an individual body, proposes a new solution for detection of fall situations utilizing the ADXL345, a 3-axis accelerometer from Analog Devices.

Free PCB Sunday: Pick your PCB

We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service.

This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB.

You get unlimited free PCBs now – finish one and we’ll send you another!

Don’t forget there’s free PCBs three times every week:

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Toorcon: HackRF low cost SDR platform


At the recent Toorcon conference in San Diego, Michael Ossmann from GreatScottGadgets presented this talk providing details on his HackRF project which we covered in a recent post. In this video Michael presents an overview of the history of SDR and details on the development of the HackRF board. Visit the HackRF project page for further details and updates.

App note: Matching MOSFET drivers to MOSFETs

Here’s an app note from Microchip detailing how to match MOSFET drivers to MOSFETs. There are many variations of MOSFETs out there, and matching one to your driver and vice-versa is essential to getting the most out of your system.

This Application Note discusses the details of MOSFET driver power dissipation in relation to MOSFET gate charge and operating frequency. It also discusses how to match MOSFET driver current drive capability and MOSFET gate charge based on desired turn-on and turn-off times of the MOSFET.

App note: DC to DC converter tutorial

Here’s a tutorial from Maxim on DC to DC converter design. Buck, boost, inverting and flyback topologies are covered. Diagrams, equations, and control techniques are available for these four common topologies.

Switching power supplies offer higher efficiency than traditional linear power supplies. They can step-up, step-down, and invert. Some designs can isolate output voltage from the input. This article outlines the different types of switching regulators used in DC-DC conversion. It also reviews and compares the various control techniques for these converters.

App note: Minimizing switching regulator residue in linear regulator outputs

Jim Williams from Linear Technology explains how to battle switching regulator residue in linear regulator outputs. If you want to clean up the switching regulator output by using a linear regulator, you’ll run into difficulties.

Linear regulators are not very good at suppressing high frequency noise, and switching regulators output loads of it. The “secret sauce” to suppress the high frequency noise is to add ferrite beads on both the input, and the output of your linear regulators. More about this is covered in the app note.

How-to: build an 8×8 LED cube kit


Chris from PyroElectro presents this post explaining the process for building an 8x8x8 LED cube (that’s 512 LEDs) from a kit. This is essentially Chris’ review of the Jameco 8×8 LED Cube Kit. He explains both how to build the LED cube and how to make the electronics that control it. Visit PyroElectro for more construction videos and details. The results look amazing, though the kit weighs in at about $140.

Via the contact form.

Workshop Update for November 9th, 2012

Sent thank yous to everyone in Bangalore. A huge thanks to Protocentral, Tenent Technetronics, NSK Electronics, Cerebra Tech, Center for Internet and Society, and all the readers who joined.

Judging on the open 7400 competition is complete. We’re hoping for a new contest next year. Most useful lab tool?

Scanning receipts from India for filing and book keeping

Open 7400 Logic Competition winners 2012

Thank you participating in the Open 7400 Competition. All the entries were amazing! Check out the full list here.

This year we tapped community members to judge, and gave great weight to the readers’ choice. The projects with the most votes were awarded prizes.

Winners will receive prize information by email in the next 48 hours. We want everyone to get a prize they can use and enjoy, so you will be able to pick your own prizes through the free PCB store. More info will be included in the notification email.

Congratulations to Umair Mukati, the 7400 Logic Based Digital Calculator was the reader’s choice and receives the Grand Prize! Umair will have first pick of the great prizes from our sponsors.

There were so many favorites, we ended up with 15 first place entries this year:

Second place winners:

Any amazing third place entries:

Thanks again for entering!

We would also like to extend our gratitude to the amazing generosity of our sponsors:

Loggrid – Power line frequency and voltage monitor/logger

Matseng is currently developing a power line frequency, and voltage monitor. The design is meant to monitor the quality of the line power and log to an SD card for later computer analysis. He is sharing his development through GitHub and discussing it in the forum.

I’m thinking of doing this project on two separate boards. One small board that measures the power line and sends the data to the display and storage board.

The main board would have a 7-segment display that would look something like the image below, showing the current time ( according to the time kept by the controller and OCXO), the number of seconds the time derived from the powerline frequency vould be off from the real time, and the current frequency + voltage of the power line.

The data would be logged in a SD memory card for later download via USB to a computer for graphing and analysis.

Via the forum.

Free PCB coupon via Facebook to 2 random commenters

Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. More PCBs via Twitter on Tuesday and the blog every Sunday.

Don’t forget there’s free PCBs three times every week:

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Video: Android app insecurity and reversing


In this just released video from the Open Web App Security Project (OWASP) AppSecUSA 2011 conference held in Minneapolis, MN, Mike Park discusses the insecurity of Android “.apk” apps and covers the ease with which Android Apps can be reversed, the ability to store sensitive data locally, and how these apps can be trojaned to access personal information on the device. He also covers open source tools for reversing and the use of the Android SDK features for pen testing.