Lesson 2--Microduino "Multiple LEDs"

Language	English

Objective After Lesson 1, you now know how to control a single LED. In this lesson, we will learn how to light up multiple LEDs one at a time. Equipment Microduino-Core Microduino-FT232R Other hardware equipment 1x Box of breadboard jumper wires 1x Breadboard 8x LEDs (Light-Emitting Diodes) 1x 220ohm resistor 1x USB Data cable Experiment Schematic As you may recall from Lesson 1, there are two ways of connecting the LEDs. Method One: Connect the negative ends (cathodes) of the LEDs to the GND port of Microduino and connect the positive ends (anodes) to digital I/O ports D3~D10. High level connection. Method Two: Connect the cathodes to the digital I/O ports D3~D10 and the anodes to VCC. Low level connection. Program Using I/O port output directly void setup() { //Define microduino digital I/O port D3~D10 as output for(int i=3;i<11;i++) pinMode(i, OUTPUT); } void loop() { for(int i=3;i<11;i++) { digitalWrite(i, HIGH); // Digital I/O port i(D3~D10) outputs high delay(50); //delay 50ms digitalWrite(i, LOW); //// Digital I/O port i(D3~D10) outputs low delay(50); //delay 50ms } } Using a hexadecimal-based array, the output data is shifted to each I/O port, allowing the user to create countless patterns with ease. /*=============================================== 1 means LED is on. 0 means LED is off. Example: 0x81:10000001 10,9,8,7,6,5,4,3 ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ 1 0 0 0 0 0 0 1 The LEDs connected to ports 10 and 3 in this case would be on. =================================================*/ long data[]= { 0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80,//From left to right light 0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01,//From right to left light 0x81,0x42,0x24,0x18,0x18,0x24,0x42,0x81,//Both sides to the middle and middle to both sides bright light 0x01,0x03,0x07,0x0f,0x1f,0x3f,0x7f,0xff,//Lit from left to right 0xff,0x7f,0x3f,0x1f,0x0f,0x07,0x03,0x01,//From right to left extinguished }; void setup() { for(int x=3;x<11;x++) { pinMode(x,OUTPUT);//Set the output pin } } void loop() { for(int x=0;x<40;x++)//Reading different pattern's lights { leddisplay(data[x]); delay(200); //Every state displays 200ms } leddisplay(0x00);//Cycle is completed, then all extinguished delay(200); } void leddisplay(int num) // Mapping the pattern matrix to the port display { /*==================================================================== Firstly right shift the hexadecimal number x bits (num >> x), x represents the microduino I/O port corresponding hexadecimal bit, 0 is the lowest bit, bit 7 is the highest bit. Then, use the bitwise AND operation with the shifted data and 0x01 to get the corresponding binary digit at port x (0 or 1). ====================================================================*/ digitalWrite(3, ((num>>0)&0x01)); digitalWrite(4, ((num>>1)&0x01)); digitalWrite(5, ((num>>2)&0x01)); digitalWrite(6, ((num>>3)&0x01)); digitalWrite(7, ((num>>4)&0x01)); digitalWrite(8, ((num>>5)&0x01)); digitalWrite(9,((num>>6)&0x01)); digitalWrite(10,((num>>7)&0x01)); } Comparing the two programs, the first looks simple, has only one pattern, and is very limited.The second program is optimized. Using an array, the hexadecimal number's each bit is assigned to the specified I/O port. Waterfall LED designs can be created using the second program. Result Program 1 LED lights are turned on and off from left to right one at a time. Program 2 A total of five patterns：LEDs turn on and off from left to right, right to left, both ends to the middle and middle to both ends, all lit from left to right, and finally extinguished from right to left. Video http://v.youku.com/v_show/id_XNzA5OTk3MjI4.html