Squonk writes Here is an interesting paper on “Very Low-Cost Sensing and Communication Using Bidirectional LEDs”. Not new (2003), but this technical report is very detailed. The abstract to the document by Mitsubishi Electric states: “A novel microprocessor interface circuit is described which can alternately emit and detect light using only an LED, two digital […]
Category Archives: how-to
Quick and easy two-way opto-isolator
Forrest M. Mims III posts this quick and easy project on Jameco’s website demonstrating how to make a simple two-way opto-isolator using two LEDs.
Open bench logic sniffer tutorial
The longhorn Engineer I was so impressed by the Open Bench Logic Sniffer that I had to make a little mini review detailing its features. Get a Logic Sniffer for $50, with free worldwide shipping. Via the contact form
How to: Mail PCBs the cheap way
Over the past two years we’ve mailed close to 1000 free PCBs all over the world. We find that a sturdy envelope and a stamp is the cheapest, and somewhat successful, way to mail PCBs. A new wiki page shows the tricks we use to mail PCBs. The how-to is reproduced here for you blog […]
From Illustrator to Eagle: Vector graphics in circuits
todbot posted tutorial on vector graphics in circuits from Illustrator to Eagle: Eagle is a great cross-platform, free-for-non-commercial-use tool for many of us designing own own circuit boards. But it has a pretty glaring omission: the ability to import vector artwork to use as board outlines, logos, etc. You can import bitmaps via the finicky […]
Sourcing parts for a new design
Charliex documented his part sourcing process for a USB isolator project.
PropController: open source platform for lighting and prop control
The PropController is a Parallax Propeller based DMX/Ethernet swiss army knife originally intended for the DIY Christmas and Halloween communities. This device acts as building block to create custom lighting and FX controllers. There are currently two versions of the PropController one for RS485 (DMX) and one for Ethernet (E1.31 – Lightweight streaming protocol for […]
Pachube controlled RGB LED
Andy from the UK was looking to build a simple proof of concept project which would integrate an Arduino and ENC28J60 based ethernet shield (or a Nanode) to connect with his Pachube account to control an RGB LED. He says: This article describes a simple application to demonstrate the ENC28J60 EtherShield library. It can be […]
Command line LCD Arduino interface
Joseph Swanson from swantron likes working with the command line. He also likes working with the Arduino. So he came up with this simple project which takes the results of his command line entries and directs them over the Linux box’s USB output to the Arduino. The Arduino then displays the data on an attached […]
Practical MC13224 firmware extraction
Travis Goodspeed wrote this article on his blog detailing his extraction of firmware from the MC13224 that had been read protected. This is the same MCU used in the Defcon 18 badge and the Redwire Econotag. He presents two methods. In one he decaps the SPI flash memory chip using nitric acid, then removes and […]
Web interactive LCD controlled by Arduino
Here’s a project by Everett Robinson which demonstrates how to use an Arduino, Ethernet shield, 2×16 LCD, a breadboard and 2K resistor to produce a web-controlled interactive LCD display. The Arduino generates a simple HTML web page showing the text currently displayed on the LCD, providing an input form to change the LCD text, resulting […]
CPLD Commodore C64 memory project
The website 64HDD has plenty of information about mods and upgrades for Commodore C64 enthusiasts. They have an article explaining their exploration of using CPLDs in C64 hardware mods. Their first CPLD project, explained in the article, explores the build of a 256kB memory expansion board originally designed using TTL chips. The project uses the […]
10-A H-Bridge motor controller
Chris from PyroElectro has posted his plans for a 10-A H-Bridge motor controller that avoids using the the typical controller ICs. He writes: Motor control is the core heart of robotics. Without locomotion or any movement a robot is dull and lifeless. The H-bridge is a tried and true concept for DC motor control. It […]
Free Digikey shipping tip
bearmos shared a tip for free Digikey shipping in the US and Canada: Here’s how to get it: 1. Add items into your shopping cart like you normally would (make sure you’re logged in when doing this). 2. Print it out. 3. Write a check for the total + tax in your area. 4. Snail […]
CPLD VGA resistor DAC
Chris from Pyroelectro informs us of his new tutorial describing the design of a VGA controller that uses a resistor DAC to create 512 unique VGA colors. He uses an Altera CPLD and VHDL code to create all the video signals. The theory, hardware schematics and software are all explained and available for viewing/download at […]
Microcontrollers and simple wireless data transfer
Getting started with microcontrollers and simple wireless data transfer: I thought you guys might like this article, it shows you how to get started using those $10 433 MHz RF tx/rx pairs. The article explains the theory, shows an example schematic for receiver/transmitter and has the project firmware for both available for download. Video below. […]
STM32VL-Discovery with ChibiOS/RT
Getting started with STM32VL-Discovery board and ChibiOS/RT: ChibiOS/RT is a complete, portable, open source, compact and extremely fast Real Time Operating System. ChibiOS/RT offers an excellent support for the STM32 platform. All drivers are “native” in order to minimize the memory footprint, the bulky ST library has not been used (but is supported). The STM32 on […]
Propeller software USB host
Beth from scanlime has posted this code for creating a USB host in software on the Parallax Propeller. Beth got interested in this concept while considering whether USB WiFi and Bluetooth modules could be interfaced to the Propeller. She wanted to see if a USB host controller could be implemented entirely in software on the […]
S/PDIF Digital Audio on the Parallax Propeller
Beth from scanlime has posted a detailed explanation of her development of an S/PDIF encoder object for the Parallax Propeller. The source code is open under an MIT-style license. If you’re a Propeller enthusiast it should be easy to implement this code to give your next sound project a digital output. Beth hopes that this […]
Logic Sniffer used in IDE bus sniffing and hard drive password recovery
Open Sesame on Prezi dop3j0e needed a way to recover the password on his ThinkPad’s hard drive after the laptop’s fingerprint scanner died (in which the password was stored.) Luckily, the drive’s IDE had 16 5V data lines just like the inputs on the OpenBench Logic Sniffer. He wired the Logic Sniffer to the lines […]