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 overclockedATmega644P, and AD725 (which has been skirted in certain incarnations).
The Atmega168 at the heart of every Arduino is an eminently capable chip; its ilk have been seen working as a basic web server, playing back digital audio, even generating TV signals. But as projects continue to grow in sophistication, reality rears its ugly head: Arduino can handle any one of these tasks very well, but it often requires squeezing every last instruction cycle or bit of memory in the device. Even the ’368 chip and the Arduino Mega are stopgap measures. Sooner or later, you have to graduate to long trousers—move up to a more capable microcontroller platform—an uncomfortable change usually involving a hefty investment in new hardware and an intimidating learning curve. Leaf Labs’ Maple aims to change all that… Read the rest of this entry »
We found this Arduino AVR ISP programmer particularly interesting. AVR microcontrollers can utilize an interface called In-System-Programming. ISP allows the chip to be programmed or reprogrammed while in an actual circuit via a pin header. Atmel’s solution is the AVR ISP MKII programing tool. The MKII can also be reprogrammed just as an AVR. The difference here is that most people are not likely to modify the MKII to be used as anything but a programmer. On the other hand if you already have the Arduino, fetch the avr.isp.03 firmware and AVRdude. Then program a device, for example an ATtiny13 using the Ardunio as the programmer. All the project information is provided under the CC BY-NC-SA 3.0 license. On a related note we covered a Microcontroller cheat sheet which covers AVR devices and ISP pinouts.
Maxim’s iButtons, which are small ICs in button-sized disks, are starting to show up in more and more places. They have a range of uses, from temperature loggers to identification, and all use the 1-wire protocol to communicate. Over a furrtek, they hacked an iButton used for buying things from vending machines and created an infinite money cheat. They built a small rig based on the ATmega8 to read and write data to the chip. The data was encrypted, so it wasn’t feasible to put an arbitrary amount on the card. Instead, they used a similar technique to the Boston subway hack and restored a previous state to the iButton after something was bought. They also created a hand-held device to backup and restore the contents of a button for portable hacking.
[Maarten] told us about a C64 USB keyboard that was modified to be used as a standard input device. An interesting aspect of the project is the use of V-USB (formerly known as AVR-USB). V-USB is a software only approach to slow speed USB HID. In essence this is a two fold mod, The C64 keyboard is patched to a PC, and an off the shelf AVR is software-hacked to bit bang the USB communications. The author notes an initial problem with multiple key presses that was later corrected in the application. For the other side of the spectrum, we had covered the C64 twittering client, and a commodore 64 laptop.
[Humberto] from NerdKits sends in the newest addition to their excellent collection of videos. This video goes over the basics of DC motor control with microcontrollers. They begin by showing nine experiments and observations that can be done by the average hacker with a multimeter, motor, LED, and jumperwire. Using the results from these they show how to model and calculate the properties of a motor. Lastly, it shows how to control a motor using PWM. They have supplemental text and demonstration code for an ATmega168 on their website.
With a user interface consisting of two buttons and a three digit display, the GPS finder guides the user back to a saved location. Nine locations can be saved for navigation recall. Press a button to save location and press another button to recall. Each switch has a secondary function, for management purposes such as memory indexes and power features. An AarLogic GPS 3A module and AVR microcontroller make up the guts. With the popularity of Geocaching, this would make an impressive trinket; Leading the hunter to an undocumented treasure.
[Alex] put together this handy cheat sheet to make pinout lookups much quicker. It covers the most common chips from the AVR line, ISP headers, and FTDI cables.
The guys over at NerdKits put together a really informative video on a meat thermometer using predictive filtering which is viewable below. The video, supplemental text, and code is available on their website. The thermometer is constructed of a LM34 temperature sensor attached to a piece of 12 gauge solid copper wire. The thermometer signal is processed on an ATmega168 microcontroller and visualized using the pygame library for python. The real gem in this project is their excellent explanation of predictive filtering, which could easily be utilized for a large number of projects.
Reader, [Lennon Luks] made a really slick MIDI sequencer/controller for his senior design project while studying at Western Carolina University. It has a grid of 64 LED buttons, 8 knobs, and a display with navigation buttons that allow him to sequence tracks with or without a computer. The controller is based off an ATmega644 and is programmed in C. [Lennon] clearly explains the inner workings of the project in detail on his website and has included a good number of pictures. [Lennon] made a nice video of the project which can be seen after the jump.
