This project allows one to use a universal IR remote to control an AVR based Etch A Sketch. For display, we use the Nokia 3310 LCD ($10 from SparkFun.com). The Etch A Sketch functionality is simply the ability to draw in a straight line up, down, left, right. The purpose of this project was to demonstrate the improvements to CC Dharmani’s NOkia 3310 library that allows per pixel access using a pixel buffer. The improved version has been included in the source of this project *
AVR based Etch A Sketch with Nokia 3310 LCD – [Link]
A couple of weeks ago, Embedded Lab posted a very basic tutorial on interfacing LED dot matrix to microcontroller (http://www.electronics-lab.com/blog/?p=11327) where the technique of displaying static characters was explained. They have recently posted the second part of that tutorial but now describing the method of scrolling characters on LED dot matrix.
Scrolling text message on an LED dot-matrix display – [Link]
The purpose of this project is to make an audio visualizer to demonstrate the use of the Nokia 3310 LCD as a graphical display. By audio visualizer, I mean the visualization like Winamp, XMMS, or Windows Media player. This project utilizes a fixed point FFT (fast fourier transform) algorithm to convert the discrete audio samples in time into frequency. This allows us to graph bars for each frequency as the music is playing. In other words, different bars dance around for the bass, midrange, treble, and all the points in between.
Audio Visualization with Nokia 3310 LCD and FFT – [Link]
SD / MMC cards support a SPI mode. By connecting it to an AVR’s SPI port, it can be used for general storage relatively easy. Here I demo the use of an SD / MMC card as general storage for electronics projects. I am using it with a 1MHz Atmel AVR atmega8, standard 2GB microSD card with adapter sleeve, and using a PWM port as a cheap DAC for sound output. I first loaded the SD card with pre-recorded sounds at 8KHz and 8-bit unsigned linear. I then read them in real time from the SD card and write the values to the OCR so that they set the duty cycle on a PWM port. I use a simple RC low pass filter as a cheap DAC (Digital to Analog Convertor) that is output to a speaker.
Use an SD or MMC card on your next AVR project – [Link]
I spent some time during Thanksgiving to build an automatic cat feeder but I’m just now getting around to writing something about it. Our cats want to be fed at 6am but I don’t want to get up to do so. This aims to get them fed and back to bed without waking us up! All the good stuff after the break.
Automatic cat feeder – [Link]
Last week on hack-a-day I saw their post on an LED Menorah that was powered by a 9v battery with the lights controlled by dip switches. I thought to myself, “gee, that’s not a very creative design”. There was redemption in the minimalist designs linked too showing a menorah soldered to a tiny2313 and one soldered to an LM2913, both without a circuit board.
LED Menorah powered by AVR tiny13 – [Link]
This instructable is meant to be a more complete explanation than others available online. Notably, this will provide more hardware explanation than is available in the LED Marquee instructable by led555.
GoalsThis instructable presents the concepts involved with shift registers and high side drivers. By illustrating these concepts with an 8×8 LED matrix I hope to provide you with the tools needed to adapt and expand to the size and layout your project calls for.
LED matrix using shift registers – [Link]
One of the biggest hurdles for the mythTV community seems to be providing an IR receiver so that you can use your remote control with it. I had been using a serial ir receiver but decided to try building my own USB receiver. This is based on the work by Dick Streefland found here: http://www.xs4all.nl/~dicks/avr/usbtiny/
USB IR Receiver – [Link]
Ian Johnston wasn’t content to use the usual RC control joystick for his RC flying. He decided to reinvent the controller using a couple of old PC joysticks, an Arduino and the Tx PCB from Thomas Scherrer’s LRS kit.
RC joystick transmitter using Arduino – [Link]