图表
这个例子展示怎么从Arduino或者Genuino发送字节数据到个人电脑，并用图表绘制结果。这个叫串口通讯，因为开发板和电脑似乎通过串口连接，即使它实际用USB接口，一个串口-USB和一个USB-串口转换器。
你可以用Arduino IDE的串口监视器来观察发送的数据，或者它可以通过 Processing (看下面的代码), Flash, PD, Max/MSP等读取。
硬件要求
- Arduino or Genuino 开发板
- 模拟传感器 (电位计, 光电池, FSR, 等等)
软件要求
- Processing 或者 Max/MSP version 5
电路图
连接电位计或者其他模拟传感器到模拟输入引脚A0
原理图
样例代码
/*
Graph
A simple example of communication from the Arduino board to the computer:
the value of analog input 0 is sent out the serial port. We call this "serial"
communication because the connection appears to both the Arduino and the
computer as a serial port, even though it may actually use
a USB cable. Bytes are sent one after another (serially) from the Arduino
to the computer.
You can use the Arduino serial monitor to view the sent data, or it can
be read by Processing, PD, Max/MSP, or any other program capable of reading
data from a serial port. The Processing code below graphs the data received
so you can see the value of the analog input changing over time.
The circuit:
Any analog input sensor is attached to analog in pin 0.
created 2006
by David A. Mellis
modified 9 Apr 2012
by Tom Igoe and Scott Fitzgerald
This example code is in the public domain.
http://www.arduino.cc/en/Tutorial/Graph
*/
void setup() {
// initialize the serial communication:
Serial.begin(9600);
}
void loop() {
// send the value of analog input 0:
Serial.println(analogRead(A0));
// wait a bit for the analog-to-digital converter
// to stabilize after the last reading:
delay(2);
}
/* Processing code for this example
// Graphing sketch
// This program takes ASCII-encoded strings
// from the serial port at 9600 baud and graphs them. It expects values in the
// range 0 to 1023, followed by a newline, or newline and carriage return
// Created 20 Apr 2005
// Updated 24 Nov 2015
// by Tom Igoe
// This example code is in the public domain.
import processing.serial.*;
Serial myPort; // The serial port
int xPos = 1; // horizontal position of the graph
float inByte = 0;
void setup () {
// set the window size:
size(400, 300);
// List all the available serial ports
// if using Processing 2.1 or later, use Serial.printArray()
println(Serial.list());
// I know that the first port in the serial list on my mac
// is always my Arduino, so I open Serial.list()[0].
// Open whatever port is the one you're using.
myPort = new Serial(this, Serial.list()[0], 9600);
// don't generate a serialEvent() unless you get a newline character:
myPort.bufferUntil('n');
// set inital background:
background(0);
}
void draw () {
// draw the line:
stroke(127, 34, 255);
line(xPos, height, xPos, height - inByte);
// at the edge of the screen, go back to the beginning:
if (xPos >= width) {
xPos = 0;
background(0);
} else {
// increment the horizontal position:
xPos++;
}
}
void serialEvent (Serial myPort) {
// get the ASCII string:
String inString = myPort.readStringUntil('n');
if (inString != null) {
// trim off any whitespace:
inString = trim(inString);
// convert to an int and map to the screen height:
inByte = float(inString);
println(inByte);
inByte = map(inByte, 0, 1023, 0, height);
}
}
*/
/* Max/MSP v5 patch for this example
----------begin_max5_patcher----------
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-----------end_max5_patcher-----------
*/
Processing 程序
用上面代码例子里的Processing程序，你可以获得一个传感值图表。随着你改变传感器的值，你会获得像下面那样的东西：
Max 代码
max补丁看起来像这样。补丁的文本在上面的代码例子里。复制文本，然后粘贴到一个新的Max窗口来看程序。
更多
- serial()
- analogRead()
- ASCIITable – 示范使用Arduino的高等的串口输出函数。
- Dimmer – 移动鼠标来改变LED灯的亮度
- Midi – 连续发送MIDI音符信息
- MultiSerialMega – 使能Arduino Mega上2个串口。
- PhysicalPixel – 通过从Processing或者Max/MSP发送数据到Arduino上，使LED开关。
- ReadASCIIString – 分析整数里一个用逗号分隔的字符串，来使一个LED灯褪色。
- SerialCallResponse – 通过一个呼-应的方法（握手）来发送多个变数
- SerialCallResponseASCII – 通过一个呼-应的方法（握手）来发送多个变数，并在发送前解码（ASCII）这些数值。
- SerialEvent – 示范使用SerialEvent()函数
- VirtualColorMixer – 从Arduino发送多个变数到你的电脑，然后在Processing或者Max/MSP上读取这些数据