Most of you already seen simple audio output trough the micro controller PWM channel, this project is very simple, and gives you a set of PC programs which are useful to convert plain text to audio stream. The firmware is basically a simple interface between the audio amplifier and PC, the data stream is received by the controller trough the serial port with 8kHz refresh rate and written directly to the PWM registers. The quality is poor but this device isn’t intended for hi-fi applications, although it is well suited for speech playback.

This can be a great alternative for LCD displays, since for mono audio you need only 1 output pin, you can seriously reduce the pin count of your application, the only disadvantage is the large memory needed to store the audio stream, luckily the SD cards are getting cheaper every day.

The 8kHz refresh rate shouldn’t pose any problem, even an 8 bit micro controller running on 8MHz clock can easily manage the SD card reading and PWM refresh, without major system overhead.

Speaking avr: [via] [link]

The project described below demonstrates the usage of LCD graphical display with the help of available demo source codes.

The LCD in the first place is a tricky device, first of all you need separate power for the back light because of the higher voltage, so the author used a break-out board from www.sparkfun.com (Nokia 6100 LCD including breakout board), this board has built in a DC/DC converter for boosting the voltage, you only need one 3.3V power source.

The second issue is the control of the LCD, fortunately these mass produced displays are well documented and frequently used by hobbyist, you find a bunch of demo code for almost any type of microcontroller. The author used the demo code found on the sparkfun site, with small modifications.

Let’s see the microcontroller, some years ago the favorite AVR used by newbies was the Atmega8, which was superseded by the Atmega48/88/168, it has the same rich features, and some improvements, this was the choice of the authors too(ATmega48).

After hooking up the LCD with the microcontroller, we need some data to display, the author used his flickr account for accessing some photos on the web, you can find the free API to access the data for phyton or other high level programming languages, the pictures after downloaded, were resized, and transferred via serial port to the microcontroller which displays the image. The rendering is quite slow because the data is sent pixel by pixel to the display, but hey, at the end you have a color picture downloaded from the web and displayed on a Nokia display.

Although it sounds to be great fun to build it, if you are a beginner, try something simpler, or at least load a simple picture from your PC.

Flickr + Nokia LCD: [Link]

]]> http://www.youritronics.com/flickr-nokia-lcd/feed/ 1 http://www.youritronics.com/fetch-flickr-images-on-a-nokia-lcd/ http://www.youritronics.com/fetch-flickr-images-on-a-nokia-lcd/#comments Mon, 23 Jun 2008 17:36:06 +0000 Florin http://www.youritronics.com/?p=1183

Alex from Tinkerlog added an interesting article about fetching Flickr images on a Nokia LCD. He used a Nokia 6100 LCD including breakout board from Sparkfun. The MCU is an ATmega48, though cheap, not the best choice as he encountered some problems with the image quality. First the image is fetched from Flickr using Beej’s Python Flickr API than the image is resized and sent to the LCD. Taken to consideration the fact that this is his first LCD project we can call it a success.

Fetch Flickr Images On A Nokia LCD: [Link]

This ATmega48 based wall clock is able to keep any kind of score and display it on its 4 digits. The score is controlled by a IR remote control powered by an ATtiny28. Also trough the remote you can set the time and configure the clock. The digits are build on pcb with 5 mm LED’s, no commercial LED digits were used.

Wall clock that controlled trough IR also keeps your score: [Download Project] – [View Project PDF]

This project presents us a modular matrix led display based on the ATmega48 micro-controller. The main feature of this modular matrix display is that you can reconfigure it to form an arbitrary lenght LED display. Due to the simplicity of the design, it is easy to extend the communications protocol to more than one display chain to increase the height of the display. In this project, both single and double row examples are shown.

Modular LED Matrix Display: [Download Project] – [View Project PDF]

This is versatile development board for AVR microcontrollers ATmega48/88/168. It is good for testing and debugging embedded programs. It has many built-in peripheries connected to microcontroller so you can use them without soldering. ATmega microcontrollers are produced by ATMEL and they include a lot of features: I/O, Timers, PWM generators, ADC, RS232, TWI, SPI, Analog Comparator, Oscillator, EEPROM These microcontrollers are very versatile, easy to program and easy to use. This is the reason why I like these microcontrollers and why I decided to make development board for them.

ATmega48/88/168 Development Board: [Via] – [Link]

This ATmega48 based project involves implementing a low-cost, high-performance bipolar stepper motor driver. The driver is designed for retrofitting a piece of equipment for CNC operation with inexpensive interpreter programs. For example this board was used to control a milling machine.

Microstepping Bipolar Stepper Motor Driver:[Download Project] – [View Project PDF]

POV is a really cool concept, similar to the way a television works, an image or series of colors is spewed out and ‘blend’ together because the light pulses occur at a speed faster than our eyes can properly observe. thus like a camera with a long exposure, we see a blur and this blur can be made directly into an image of your choosing.

DIY POV(Persistence of Vision): [Link]

This digital dashboard powered by an ATmega48 microcontroller, can be integrated as described in this project into an old tractor, displaying on the LCD screen important info like RPM, Oil temperature or battery voltage.

Add a digital dashboard to an old tractor: [Download Project] – [View Project PDF]