How To Write Udev Rules

September 18, 2009 by Mike Szczys 36 Comments

Since the adoption of Kernel 2.6, Linux has used the udev system to handle devices such as USB connected peripherals. If you want to change the behavior when you plug something into a USB port, this section is for you. As an example, we will use a USB thumb drive but these methods should translate to any device handled by udev. As a goal for this exercise we decided to create a symlink and execute a script when a specific thumb drive was loaded. The operating system we used for this exercise is Ubuntu 9.04 Jaunty Jackalope. Continue reading “How To Write Udev Rules” →

Touch Sensitive Keypad

September 18, 2009 by Mike Szczys 12 Comments

capacitive_keypad

[Viacheslav] built a keypad that uses human capacitance to detect key presses. Unlike normal keys which close a physical connection, his project detects touch through the PCB substrate. He uses the analog comparator of an AVR ATmega8 to detect the moment of zero crossing and then measures the time it takes to discharge in order to detect key presses.

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Software Pulse Width Modulation

September 17, 2009 by Mike Szczys 11 Comments

daqq_pwm_schematic

Pulse Width Modulation is a topic that tends to give a lot of beginners trouble. [Daqq], whose nixie plasma ball we covered a few days ago, has a simple but effective PWM project that you should take a look at. The circuit used 9 LEDs clustered together into 3 sets of RGB modules and connected them to an AVR ATtiny2313 through some current limiting resistors. Most of the time the PWM function of the AVR’s timers would be used to generate the signal but this application calls for 9 signals which is more than can be produced by this chip. The workaround is to generate the signals using software PWM. Continue reading “Software Pulse Width Modulation” →

Arduino Command Interpreter Shell

September 17, 2009 by Matt Schulz 18 Comments

F77LQEPFYTCLILR.MEDIUM

A lot of people like fancy GUIs and nice graphics, but some of us just feel more at home in a command prompt. [nevdull] is one of those people. Instead of just using the Arduino dev tools that are available for download, he wanted the ability to shell into his Arduino, so he created AVR Shell. AVR Shell is a UNIX-like shell that allows you to “log in” to your Arduino/AVR and see what’s really going on; letting you read registers, scale the CPU speed, create/edit/delete variables, and even set up timers. The shell is even user-customizable! Those of you interested in Arduino shells might also check out bitlash, another open source CLI. Someone ought to hook this up to the Internet enabled Furby and get Flite compiled on there, letting us shell into a Furby from miles away to make it talk.

[Thanks Leesam]

Uzebox Video Player

September 10, 2009 by Jake W 12 Comments

[youtube=http://www.youtube.com/watch?v=hWWsSn_QKLM]
Everyone’s favorite open source game console, the Uzebox (also cloned as the Fuzebox), just got a new feature hacked into it – a video player. At reduced quality (8-bit color), the Uzebox was able to play ‘The Matrix’ off an SD card @ 30fps plus the audio @15kHz. That’s a pretty impressive feat when one considers it is running on 4096 bytes of RAM. The video file had to first be converted into a series of pictures through a Photoshop macro in order to be playable. A Uzebox can be built with little more than a few resistors in addition to an overclocked ATmega644P, and AD725 (which has been skirted in certain incarnations).

Snega2usb Update: Usb Snes And Sega Cartridge Reader

September 7, 2009 by Gerrit Coetzee 32 Comments

[youtube=http://www.youtube.com/watch?v=QNBg_jWjBmI]

When we first posted [Matthias_H]’s USB reader for SNES game carts, it was met with enthusiasm. The snega2usb allows you to play SNES and Sega games on your pc right off the cartridge. The latest revision is even more amazing than the first. [Matthias] has added the ability to read Sega Genesis/Mega Drive cartridges as well as the ability to save games directly to the cartridge. The board has also been updated from the rats nest it used to be to a smart looking dual sided PCB. So far [Matthias] hasn’t had any trouble reading cartridges, even ones with the SuperFX chips. [Matthias] also launched a site for the project where the lastest information on its development can be found. [Matthias] is getting close to a production version which will feature better firmware, console quality connectors and a shiny case.

Simple Automatic LED Lamps

September 2, 2009 by Mike Szczys 12 Comments

simple_led_lamps

[woody1189] put together some automatic lighting for his closet. Nine LEDs are grouped into three lamps and controlled by a hall effect sensor. He prototyped this on an Arduino and then migrated over to an ATtiny85. Although the current implementation could be accomplished without a microcontroller, we’d love to see some firmware improvements such as an auto shutoff for when you forget to close the closet door. The hall effect sensor seems to pop up in a lot of projects so make sure you get a few of them with your next parts order. Video of this in action after the break.

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