Step 1) If you haven’t install mBlock software in your PC, please read Lesson 1, download and install the software. Then connect the RGB module to the RGB port of the Magic I/O shield with a 4-pin PNP cable as below: Osoyoo UNO Board (Fully compatible with Arduino UNO rev.3) x 1įirstly, please plug Osoyoo Magic I/O shield into UNO board as following:.However, the brightness is equal to the sum of all brightness, and the more you mix, the brighter the LED is. When superimposing the light emitted by the three primary colors, the colors will be mixed. ![]() When the three primary colors are all 255, “LED light” is the brightest. When the three primary colors are all 0, “LED light” is the darkest, that is, it turns off. If you say the color displayed doesn’t completely match a natural color, then it almost certainly cannot be differentiated with the naked eyes.Įach of the three color channels of red, green, and blue has 255 stages of brightness. RGB displays various new colors by changing the three channels and superimposing them, which, according to statistics, can create 16,777,216 different colors. RGB stands for the red, green, and blue color channels and is an industry color standard. If the frequency of the signal is fast enough, then there will be no visible flicker, and the LED’s brightness will be proportional to the signal’s duty cycle. During the 10% duty cycle, the signal is at the logic high level for only a brief time each cycle, but with 90% duty cycle, most of the signal’s period is spent at logic high level. In the following figure, we show three different duty cycles, first with 50% duty cycle, then 10% and 90% duty cycle. Pulse-width modulation (PWM) is the practice of modulating the duty cycle of a signal, used in this application to control the average power sent to each LED. By turning our LED on and off rapidly, we can trick the brain into seeing an “average” value of brightness based on the duty cycle of the driving PWM signal. This this the same principle behind film and television, where a rapidly changing image tricks your brain into seeing continuous motion. Persistence of vision is the phenomenon where an image that is seen for only a fraction of a second will continue to be “seen” by your brain even after the original image has vanished or moved. Fortunately, human vision has a nice phenomenon called persistence of vision. The brightness of an LED is proportional to the current going through it, but it would be rather difficult to use a microcontroller to accurately control the current flowing through an LED. So the closest we can come to black with our LED is to turn off all three colors. ![]() We can control the brightness of each of the red, green and blue parts of the LED separately, making it possible to mix any color we like.īlack is not so much a color as an absense of light. If we turn off the blue LED, so that just the red and green LEDs are the same brightness, then the light will appear yellow. If we set the brightness of all three LEDs to be the same, then the overall color of the light will be white. You can create one of those three colors – red, green or blue – by activating just one LED.įor example, if you want to produce blue, you activate the blue LED and turn off the other two. ![]() This same idea is used in TVs, where the LCD has red, green and blue color dots next to each other making up each pixel. In a way, by using the three LEDs we are playing a trick on the eye. Your eye and brain process the amounts of red, green and blue and convert it into a color of the spectrum. The reason that you can mix any color you like by varying the quantities of red, green and blue light is that your eye has three types of light receptor in it (red, green and blue).
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