We have RGB LED matrix in iStore, but have not the RGB LED driver board to drive them. Many customers buy them and use with the Rainbowduino, which it’s basis on Arduino. It’s really a cool design which make it so easy to drive the RGB LED matrix, you don’t need to know much about the driver circuit but just use the Arduino IDE you can make many beautiful display.
The Rainbowduino said that it support 4096 colors (even 32768 colors), the Rainbowduino using the software to simulate PWM for make up the different color level, it looks like a good idea but in fact it is consuming resources and not inaccurate. Also it’s difficult to correct the color deviation.
We decided to make a more professional driver platform for RGB LED matrix which drive the LEDs by hardware PWM and with software color deviation correction, so now the Colorduino comes out.
Colorduino be designed to compatible with Rainbowduino as much as possible, also easy plug and shine – you don’t need to care about the circuit. Even we use the same IIC, UART interface as Rainbowduino, try connect them in series and they should work together. We hope that we can provide you the Colorduino APP which also compatible with Rainbowduino’s , so you don’t need to modify any code in master to control the LED platform.
The Colorduino is basis on ATMega 168P/328P, the same as Rainbowduino. This design is to make user easily modify or write the firmware of Colorduino by Arduino IDE. But in order to better drive the RGB matrix and reach their best performance, we use the professional LED driver chip, and this chip comprises shift registers, data latches, 8×3 channel constant current and 64 x 256 gray level PWM for per color! Each channel provide a maximum current of 60 mA.
Each RGB dot has 256×256×256 = 16,777,216 colours (16 million) in theory, and it’s easy to use the 6bit correction register to calibrate the current error for each color LEDs – we don’t think that Rainbowduino use an adjustable resistors to calibrate the current error is a good idea, because just 1 lap the resistor change from 0R to1K , you cannot get the exact value you need, but now, you have a 6bit software value to correct it.
We will release more information about Colorduino in next post, now we has finished the hardware design and making some software job. It will in stock after the Spring Festival, now we are still thinking that what color for the official version : )