Seg 1: How to control LED from bright to dim by Arduino

4.1 Problem presentation: how to control LED from bright to dim by Arduino

In the previous examples, Arduino is just used to control the brightness and/or dark for LED. That is, there are only two voltage levels: high and/or low from the voltage level, and there are only two digital value: 0 and/or 1 from the digital signal. But, Arduino doesn’t control the continuous variation from bright to dim, or visa. Moreover, the applied requirements exist in our usual lives, such as dancing hall, or concern. For the lighting effects, sometimes, we need a gradual change for the LED lights from bright to dim. This can be realized by giving a continuous voltage to a LED light. Therefore, in our such experiment, by utilizing the PWM (Pulse Width Modulation) technique, Arduino can transmit a continuous voltage signal to control LED, and the PWM technique is also widely used in the continuous operation of steering gear, music play, and power control in the communication.

4.2 The required materials

The required materials are very simple in this sample, which is similar to the experiment one. It is different from the connected port on the Arduino, as shown in Figure 4-1.

Table 4-1: Materials

The required materials


Name Quality Function Note


Arduino software 1 suit Provide ide New ver 1.05


Arduino UNO board 1 Control board Many


USB data line 1 Connect board distribution


Dupont line 2 Connect elements optional


Light-emitting diode (led) 1 LED blink optional


Resistance 220Ω Current limiting optional


Bread board Connection optional

The required materials can be referred in the following Figure 4-5.

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