我正在使用两个Arduinos使用newsoftserial和RF收发器向对方发送纯文本字符串。
每个字符串的长度可能是20-30个字符。如何将Serial.read()
转换为字符串,以便我可以if x == "testing statements"
等等?
答案 0 :(得分:111)
无限字符串重写
String content = "";
char character;
while(Serial.available()) {
character = Serial.read();
content.concat(character);
}
if (content != "") {
Serial.println(content);
}
答案 1 :(得分:60)
来自 Help with Serial.Read() getting string :
char inData[20]; // Allocate some space for the string
char inChar=-1; // Where to store the character read
byte index = 0; // Index into array; where to store the character
void setup() {
Serial.begin(9600);
Serial.write("Power On");
}
char Comp(char* This) {
while (Serial.available() > 0) // Don't read unless
// there you know there is data
{
if(index < 19) // One less than the size of the array
{
inChar = Serial.read(); // Read a character
inData[index] = inChar; // Store it
index++; // Increment where to write next
inData[index] = '\0'; // Null terminate the string
}
}
if (strcmp(inData,This) == 0) {
for (int i=0;i<19;i++) {
inData[i]=0;
}
index=0;
return(0);
}
else {
return(1);
}
}
void loop()
{
if (Comp("m1 on")==0) {
Serial.write("Motor 1 -> Online\n");
}
if (Comp("m1 off")==0) {
Serial.write("Motor 1 -> Offline\n");
}
}
答案 2 :(得分:52)
您可以使用Serial.readString()
和Serial.readStringUntil()
来解析Arduino上Serial的字符串。
您还可以使用Serial.parseInt()
从串行读取整数值。
int x;
String str;
void loop()
{
if(Serial.available() > 0)
{
str = Serial.readStringUntil('\n');
x = Serial.parseInt();
}
}
通过序列发送的值为my string\n5
,结果为str = "my string"
和x = 5
答案 3 :(得分:11)
我自己也在问同样的问题,经过一番研究后我找到了类似的东西。
它对我来说就像一个魅力。我用它来远程控制我的Arduino。
// Buffer to store incoming commands from serial port
String inData;
void setup() {
Serial.begin(9600);
Serial.println("Serial conection started, waiting for instructions...");
}
void loop() {
while (Serial.available() > 0)
{
char recieved = Serial.read();
inData += recieved;
// Process message when new line character is recieved
if (recieved == '\n')
{
Serial.print("Arduino Received: ");
Serial.print(inData);
// You can put some if and else here to process the message juste like that:
if(inData == "+++\n"){ // DON'T forget to add "\n" at the end of the string.
Serial.println("OK. Press h for help.");
}
inData = ""; // Clear recieved buffer
}
}
}
答案 4 :(得分:4)
这会更容易:
char data [21];
int number_of_bytes_received;
if(Serial.available() > 0)
{
number_of_bytes_received = Serial.readBytesUntil (13,data,20); // read bytes (max. 20) from buffer, untill <CR> (13). store bytes in data. count the bytes recieved.
data[number_of_bytes_received] = 0; // add a 0 terminator to the char array
}
bool result = strcmp (data, "whatever");
// strcmp returns 0; if inputs match.
// http://en.cppreference.com/w/c/string/byte/strcmp
if (result == 0)
{
Serial.println("data matches whatever");
}
else
{
Serial.println("data does not match whatever");
}
答案 5 :(得分:2)
最好和最直观的方法是使用serialEvent()回调Arduino定义循环()和setup()。
我已经建立了一个处理消息接收的小型库,但从未有时间开源它。 该库接收\ n终止的行,这些行表示命令和任意有效载荷,以空格分隔。 您可以轻松调整它以便轻松使用自己的协议。
首先,一个库,SerialReciever.h:
#ifndef __SERIAL_RECEIVER_H__
#define __SERIAL_RECEIVER_H__
class IncomingCommand {
private:
static boolean hasPayload;
public:
static String command;
static String payload;
static boolean isReady;
static void reset() {
isReady = false;
hasPayload = false;
command = "";
payload = "";
}
static boolean append(char c) {
if (c == '\n') {
isReady = true;
return true;
}
if (c == ' ' && !hasPayload) {
hasPayload = true;
return false;
}
if (hasPayload)
payload += c;
else
command += c;
return false;
}
};
boolean IncomingCommand::isReady = false;
boolean IncomingCommand::hasPayload = false;
String IncomingCommand::command = false;
String IncomingCommand::payload = false;
#endif // #ifndef __SERIAL_RECEIVER_H__
要使用它,请在项目中执行以下操作:
#include <SerialReceiver.h>
void setup() {
Serial.begin(115200);
IncomingCommand::reset();
}
void serialEvent() {
while (Serial.available()) {
char inChar = (char)Serial.read();
if (IncomingCommand::append(inChar))
return;
}
}
使用收到的命令:
void loop() {
if (!IncomingCommand::isReady) {
delay(10);
return;
}
executeCommand(IncomingCommand::command, IncomingCommand::payload); // I use registry pattern to handle commands, but you are free to do whatever suits your project better.
IncomingCommand::reset();
}
答案 6 :(得分:2)
如果您想从串口读取消息,并且需要单独处理每条消息,我建议使用这样的分隔符将消息分成几部分:
String getMessage()
{
String msg=""; //the message starts empty
byte ch; // the character that you use to construct the Message
byte d='#';// the separating symbol
if(Serial.available())// checks if there is a new message;
{
while(Serial.available() && Serial.peek()!=d)// while the message did not finish
{
ch=Serial.read();// get the character
msg+=(char)ch;//add the character to the message
delay(1);//wait for the next character
}
ch=Serial.read();// pop the '#' from the buffer
if(ch==d) // id finished
return msg;
else
return "NA";
}
else
return "NA"; // return "NA" if no message;
}
这样,每次使用此功能时都会收到一条消息。
答案 7 :(得分:2)
这是一个更强大的实现,可以处理异常的输入和竞争条件。
它故意使用字符数组而不是String
类型,以提高效率并避免内存问题。它还避免使用readStringUntil()
函数,在输入到达之前不会超时。
原始问题没有说明如何定义可变长度字符串,但我假设它们被一个换行符终止 - 这会将其转换为行阅读问题。
int read_line(char* buffer, int bufsize)
{
for (int index = 0; index < bufsize; index++) {
// Wait until characters are available
while (Serial.available() == 0) {
}
char ch = Serial.read(); // read next character
Serial.print(ch); // echo it back: useful with the serial monitor (optional)
if (ch == '\n') {
buffer[index] = 0; // end of line reached: null terminate string
return index; // success: return length of string (zero if string is empty)
}
buffer[index] = ch; // Append character to buffer
}
// Reached end of buffer, but have not seen the end-of-line yet.
// Discard the rest of the line (safer than returning a partial line).
char ch;
do {
// Wait until characters are available
while (Serial.available() == 0) {
}
ch = Serial.read(); // read next character (and discard it)
Serial.print(ch); // echo it back
} while (ch != '\n');
buffer[0] = 0; // set buffer to empty string even though it should not be used
return -1; // error: return negative one to indicate the input was too long
}
以下是用于从串行监视器读取命令的示例:
const int LED_PIN = 13;
const int LINE_BUFFER_SIZE = 80; // max line length is one less than this
void setup() {
pinMode(LED_PIN, OUTPUT);
Serial.begin(9600);
}
void loop() {
Serial.print("> ");
// Read command
char line[LINE_BUFFER_SIZE];
if (read_line(line, sizeof(line)) < 0) {
Serial.println("Error: line too long");
return; // skip command processing and try again on next iteration of loop
}
// Process command
if (strcmp(line, "off") == 0) {
digitalWrite(LED_PIN, LOW);
} else if (strcmp(line, "on") == 0) {
digitalWrite(LED_PIN, HIGH);
} else if (strcmp(line, "") == 0) {
// Empty line: no command
} else {
Serial.print("Error: unknown command: \"");
Serial.print(line);
Serial.println("\" (available commands: \"off\", \"on\")");
}
}
答案 8 :(得分:2)
String content = "";
char character;
if(Serial.available() >0){
//reset this variable!
content = "";
//make string from chars
while(Serial.available()>0) {
character = Serial.read();
content.concat(character);
}
//send back
Serial.print("#");
Serial.print(content);
Serial.print("#");
Serial.flush();
}
答案 9 :(得分:1)
如果您正在使用连接方法,那么如果您正在使用if else方法,请不要忘记修剪字符串。
答案 10 :(得分:1)
在serial.read()上使用字符串追加运算符。它比string.concat()
更好char r;
string mystring = "";
while(serial.available())
{
r = serial.read();
mystring = mystring + r;
}
完成将流保存在字符串中后(在本例中为mystring),使用SubString函数提取您要查找的内容。
答案 11 :(得分:1)
归功于岩浆。很好的答案,但这里使用的是c ++样式字符串而不是c样式字符串。有些用户可能会觉得更容易。
String string = "";
char ch; // Where to store the character read
void setup() {
Serial.begin(9600);
Serial.write("Power On");
}
boolean Comp(String par) {
while (Serial.available() > 0) // Don't read unless
// there you know there is data
{
ch = Serial.read(); // Read a character
string += ch; // Add it
}
if (par == string) {
string = "";
return(true);
}
else {
//dont reset string
return(false);
}
}
void loop()
{
if (Comp("m1 on")) {
Serial.write("Motor 1 -> Online\n");
}
if (Comp("m1 off")) {
Serial.write("Motor 1 -> Offline\n");
}
}
答案 12 :(得分:0)
我可以逃脱这个:
{{1}}
答案 13 :(得分:0)
Many great answers, here is my 2 cents with exact functionality as requested in the question.
Plus it should be a bit easier to read and debug.
Code is tested up to 128 chars of input.
Tested on Arduino uno r3 (Arduino IDE 1.6.8)
Functionality:
Commands:
Note: Remember to change baud rate based on your board speed.
// Turns Arduino onboard led (pin 13) on or off using serial command input.
// Pin 13, a LED connected on most Arduino boards.
int const LED = 13;
// Serial Input Variables
int intLoopCounter = 0;
String strSerialInput = "";
// the setup routine runs once when you press reset:
void setup()
{
// initialize the digital pin as an output.
pinMode(LED, OUTPUT);
// initialize serial port
Serial.begin(250000); // CHANGE BAUD RATE based on the board speed.
// initialized
Serial.println("Initialized.");
}
// the loop routine runs over and over again forever:
void loop()
{
// Slow down a bit.
// Note: This may have to be increased for longer strings or increase the iteration in GetPossibleSerialData() function.
delay(1);
CheckAndExecuteSerialCommand();
}
void CheckAndExecuteSerialCommand()
{
//Get Data from Serial
String serialData = GetPossibleSerialData();
bool commandAccepted = false;
if (serialData.startsWith("LED.ON"))
{
commandAccepted = true;
digitalWrite(LED, HIGH); // turn the LED on (HIGH is the voltage level)
}
else if (serialData.startsWith("LED.OFF"))
{
commandAccepted = true;
digitalWrite(LED, LOW); // turn the LED off by making the voltage LOW
}
else if (serialData != "")
{
Serial.println();
Serial.println("*** Command Failed ***");
Serial.println("\t" + serialData);
Serial.println();
Serial.println();
Serial.println("*** Invalid Command ***");
Serial.println();
Serial.println("Try:");
Serial.println("\tLED.ON");
Serial.println("\tLED.OFF");
Serial.println();
}
if (commandAccepted)
{
Serial.println();
Serial.println("*** Command Executed ***");
Serial.println("\t" + serialData);
Serial.println();
}
}
String GetPossibleSerialData()
{
String retVal;
int iteration = 10; // 10 times the time it takes to do the main loop
if (strSerialInput.length() > 0)
{
// Print the retreived string after looping 10(iteration) ex times
if (intLoopCounter > strSerialInput.length() + iteration)
{
retVal = strSerialInput;
strSerialInput = "";
intLoopCounter = 0;
}
intLoopCounter++;
}
return retVal;
}
void serialEvent()
{
while (Serial.available())
{
strSerialInput.concat((char) Serial.read());
}
}
答案 14 :(得分:0)
这总是对我有用:)
String _SerialRead = "";
void setup() {
Serial.begin(9600);
}
void loop() {
while (Serial.available() > 0) //Only run when there is data available
{
_SerialRead += char(Serial.read()); //Here every received char will be
//added to _SerialRead
if (_SerialRead.indexOf("S") > 0) //Checks for the letter S
{
_SerialRead = ""; //Do something then clear the string
}
}
}