Author Archives: the machinegeek

CVSD audio compression codec in an FPGA

In this video Jeri Ellsworth demonstrates her design of a Continuously Variable Slope Delta (CVSD) audio compression codec in an FPGA. She was in need of a replacement for a damaged HC-55564 IC from (where else) a pinall machine and reverse engineered the chip, coding up a replacement in a Xilinx FPGA on a Papilio […]

HC-SR04 ultrasonic Arduino library

Carl Nobile has developed and released an Arduino library covering the HC-SR04 ultrasonic sensor. He writes: “It features timing, metric conversion, and standard deviation methods, plus a few support methods. It is written in C++ to conserve the namespace. The conversion formula can be easily modified to optimize the accuracy of conversion at different distances […]

Nike+iPod reverse engineering (protocol too)

Dmitry Grinberg informs us of his latest project reverse engineering the Nike + iPod protocol. Basically this is a wireless protocol used by Nike to communicate data from certain shoe products to programs running on an iPod or iPhone. He says: “Nike+iPod is a very interesting piece of hardware for all kinds of reasons, not […]

Voice controlled robotic arm tutorial

Algorhythmic has posted a multi-part tutorial at aonsquared describing how to build a voice controlled robotic arm. While recovering from a wrist injury he decided to assemble and experiment with a robotic arm controlled by USB using notbrainsurgery’s protocol. After getting accustomed to the interface he decided to take it one step further and add […]

Plus Too Apple replica on FPGA

Steve Chamberlin over at Big Mess o’Wires presents the Plus Too, a working hardware replica of the Macintosh Plus and Macintosh 512Ke computers. The original Macs contained a Motorola 68000 CPU and about half a dozen major support chips, with all of the Mac-specific behaviors and OS routines defined in a 128K toolbox ROM. Plus […]

DIY Arduino Ambilight using ShiftBrites

Don built an Amblight for his home theater PC. He put together this tutorial describing his build of a multichannel Arduino-based Ambilight. He estimates the BOM at $40 (in addition to the Arduino). The bill of materials include 6+ ShiftBrites (your call, I wouldn’t do less than 6 though), a printed circuit board, wire, and […]

Free O’Reilly webcast: Core Network Protocols

O’Reilly is offering a free webcast on “Core Network Protocols: Two techniques you need to know.” The 60 minute presentation by Bruce Hartpence will be live this Friday, October 14, 2011, at 1 PM PT. In this webcast we’ll talk about address space, the purpose of the network mask and the reasons we manipulate network […]

Arduino based talking breathalyzer

The Hoz sent in a link to this Instructables by alinke detailing the build of a talking breathalyzer. The main components are a Seeeduino and the Seeed Music Shield, Twig Alcohol Sensor, and Twig Serial LCD all available from Seeedstudio. The open source code and other details can be downloaded from The Talking Breathalyzer site. […]

NuttX RTOS

If you’re into using an RTOS with your MCU board, you might want to check out NuttX. NuttX RTOS is a real time embedded operating system for 8-bit to 32-bit MCUs. Its goals are to achieve a high degree of standards compliance (POSIX and ANSI) while maintaining a small footprint. It’s compatible with various MCU […]

Parallax introduces laser range finder

Parallax has introduced the Laser Range Finder. “Designed in conjunction with Grand Idea Studio, the Parallax Laser Range Finder (LRF) Module is a distance-measuring instrument that uses laser technology to calculate the distance to a targeted object. The design uses a Propeller processor, CMOS camera, and laser diode to create a low-cost laser range finder. […]

Hackerspaces – the beginning (the book)

Bre and Astera over at Hackerspace blog have assembled a detailed history of the hackerspace movement. Covering from their inception in 2008 to date, what they initially believed would be a 25 page booklet has turned into a 182 MB zip file containing a comprehensive, richly illustrated, community generated account of every aspect of hackerspace […]

DraftSight free 2D CAD product

N S K Chaitanya wrote in about an open source CAD program: I just came across a software called DraftSight. It is an open source alternative to autocad. It is by Dassault Systemes and even runs on Linux. Finally Linux has DWG support… According to Dassault Systemes, DraftSight is a “no-cost, easy-to-use 2D CAD product […]

Reference data for radio engineers, circa 1946

If you’re interested in reading about state of the art radio engineering data from way back in the day, then this may be for you.Tubebooks.org has a free download of Federal Telephone and Radio Corporation’s 1946 “Radio Data for Engineers, Second Edition” waiting for you. The 335 page PDF has loads of conversion factors, math, […]

Review: VPN1513 GPS receiver module

The VPN1513 GPS Receiver Module is a newly released combination GPS receiver and Parallax Propeller mini dev board. It uses a SiRF Star III chipset capable of tracking up to 20 satellites. The module supports both “raw” output mode for raw NMEA 0183 strings and the default “smart” mode for specific user-selected data through a […]

Arduino & iPhone = GSR lie detector

Anna Dumitriu, Tom Keene and Alex May recently gave a presentation at 17th International Symposium on Electronic Art in Istanbul demonstrating how to build an Arduino to iPhone/Android interface with GSR sensor. A GSR sensor connects to an Arduino board. The Arduino generates an audio tone mapped to value of electrical resistance in the skin. […]