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The controller is actually just an ATTiny2313, running of it’s internal RC oscillator at 8MHz, soldered onto an universal board with a few resistors and wires. There are no control items – no buttons, no nothing. It just does what it does – makes the effect of LEDs randomly fading in and out using 9 channels of PWM. Unfortunately, the processor has only a few hardware PWM channels, so some of the channels had to be done by software.

RGB LED Controlled By An ATTtiny2313: [Link]

Mobile infrared electronic transmitter

RGB LED PWM Control Project

The RGBLED and mRGBLED controllers allow you to control the color of RGBLEDs.  This might sound trivial, but it actually takes a lot of resources to let you be able to set an RGBLED to any color you’d like.  In addition to just lighting an LED up with a given color, these boards also let you install a color or setup transition/animations effects.  They are easily controller via an RS232 connection (serial port) or an SPI connection (logic level).

The boards can be built reasonably inexpensively and there are PC boards available for either model.  All source code for the onboard PIC processor as well as the software for configuring and using the controllers is available.  The protocol is a simple protocol well documented.

I’m currently studying timers and pwm control on AVR’s so i can build my own projects related to controlling RGB LED’s. I hope I’ll get something up soon.

RGB LED PWM Control Project: [Link][via]

AVR Butterfly is an evaluation tool demonstrating the capabilities of the latest AVR Technology. The tool is shipped with preloaded firmware supporting temperature sensing, light measurement, voltage readings and music playback. The AVR Butterfly is controlled by an ATmega169.

It’s basically the cheapest development board on the market, $21.28 as we’re speaking at Digikey. I choose to start with the AVR Butterfly because it is also featured in all examples in the tutorial I’m reading. The tutorial is easy to follow and i recommend it if you want to start programming AVR’s in C language. You can find it at SmileyMicros.

The tutorial contains all you need to now, but some things are not entirely covered, and other things present incompatibility issues.

When ordering the Butterfly its also a good idea to order some pin headers because they are not included. When you take the Butterfly out of the box it should look like this:


Now it would be nicer if they would of included those pin headers in the package. And here is my Butterfly after i soldered the pin headers.


Another thing that i noticed about this step, is that my Butterfly doesn’t have the LDR, it seems that this version only comes with the NTC soldered on the back, which is also an analog sensor and it should be enough for developing code with analog sensors.

The next important thing that you need to solder is the RS232 cable, because the communication between the computer and the Butterfly is done via RS232.

Hers is a picture of my cable, and how it should be done. (disregard the connector i used, its taken from an old computer case, that’s why its saying turbo sw).


Notice how the RXD and TXD from Butterfly are reversed on the RS232 connector ? That’s because what you transmit here has to be received there. Pay attention on soldering this connector, you will avoid future headaches. But what if you don’t have an RS232 connector on your computer ? the answer is simple you buy a RS232 to USB converter cable, like i did:


I could of done myself the cable using the schematic from this article, but the parts cost more than a commercial cable, not to mention the hours you put in fabricating.

Now about the battery, the onboard CR2450 isn’t gonna last too long with the projects that you’re gonna work with. So its best to build an external power supply. I build mine with 2 x AA-R6 battery holder.

2xaa-battery-external-power-supply-for-avr-butterfly avr-butterfly-with-pin-headers-soldered-and-power avr-butterfly-with-external-power-connected

From this step on, you can approach things two ways, either use a breadboard or fabricate PCB’s. I don’t have a breadboard so i had to make pcb’s. Basically its just a board with 8 LED’s, 8 current limiting resistors and some headers for linking it to the Butterfly.

here is the Eagle schematic and board file.

details on how to fabricate the PCB are covered in my DIY PCB Tutorial.

Here are a couple of pictures with the board after being etched and after being assembled. The 8 LED board is going to be used with the Blinky Project.

boards-after-beeing-etched 8-led-board-after-beeing-assembled

I also did two small PCB’s for driving an RGB LED, one for a CA version and one for CC version.(Common Anode and Common Cathode). I will use this boards later when i will be experimenting with PWM control.

Here are the RGB LED boards assembled.


And to end this article here is a picture with the USB to RS232 cable connected to the AVR. Now all i have to do is read and learn the next 300 pages from the tutorial.


Now i started working on a lab power supply, i could of just buy one but its more fun to build it. Here is a picture where i just started the assembly. The project should be up soon at my personal projects page.

May 12th, 2008

ATmega16 RGB LED Display

ATmega16 RGB LED Display

The goal was to design a home made LED Display that can be expanded to bigger sizes with minimal costs. Unlike other systems, on this one the image gets scanned mechanically and the image is created by using the POV effect (persistence of vision). There are 32 RGB LED used in the project but you can easily increase the number of LED’s. The author attached the system to a spinning fan, and the images started to appear.

ATmega16 RGB LED Display: [Download Project][View Project PDF]

Fading RGB LED with PWM Controll

The circuit is very simple. The RGB LED is hooked up to the PWM outputs on PORTB1 , PORTB2 and PORTB3 of the ATMega8. There is also a resistor between the LED and the ATmega8 to limit the current to 20mA. There is also a link to the datasheet of the RGB LED that is used in this project.

The code for the fading LED is written in assembler with the AVR Studio 4. In this example the LEDs will fade in and out one by one. The PWM timers of the ATMega8 are used to let the LED’s fade in and out. To use the PWM timers you first need to initialize the timers at the begin of the program code. The speed of the fading in and out can be changed with changing the clock speed of the ATM8.You can copy and paste the textfile into the AVR Studio 4.

Fading RGB LED with PWM Controll: [Link]

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