我正在尝试让树莓派通过串行与 arduino 进行通信，硬件已全部设置好，并且有一些通信正常。
我遇到的问题是传递的参数与 if、else if 表达式不匹配，但实际上应该与返回的内容不匹配。
SerialCommand 库处理什么命令触发什么功能。对于这个例子，我们只对 sayHello() 感兴趣。RaspberryPi 发送“HELLO HELLO”，它应该收到“YES HELLO”，但我总是收到“NO HELLO”，表明 arg HELLO 不匹配。显然，无论收到什么论点都会得到回应，我会收到应该匹配的东西，你好，所以我在这个阶段被难住了，有什么建议吗？
编辑：感谢 Thanushan Balakrishnan 在下面的回答中发表评论，替换
if(arg == "HELLO")
下面解决了这个问题。
if(strcmp("HELLO", arg) == 0)
_
// Demo Code for SerialCommand Library
// Steven Cogswell
// May 2011
// temp & Humidity
#include <DHT22.h>
#define DHT22_PIN 12
// Setup a DHT22 instance
DHT22 myDHT22(DHT22_PIN);
// tank water level
int sensorValue = 0;
int constrainedValue = 0;
int tankLevel = 0;
#define TANK_SENSOR 0
#define TANK_EMPTY 0
#define TANK_FULL 1023
/*RelayBrd */
//Pin connected to latch pin (ST_CP) of 74HC595
const int latchPin = 4;
//Pin connected to clock pin (SH_CP) of 74HC595
const int clockPin = 3;
////Pin connected to Data in (DS) of 74HC595
const int dataPin = 2;
boolean thisState = LOW;
#include <SerialCommand.h>
#define arduinoLED 13 // Arduino LED on board
SerialCommand sCmd; // The demo SerialCommand object
void setup() {
pinMode(arduinoLED, OUTPUT); // Configure the onboard LED for output
digitalWrite(arduinoLED, LOW); // default to LED off
//mySerial.begin(9600);
//mySerial.println("Ready");
Serial.begin(115200);
// Setup callbacks for SerialCommand commands
sCmd.addCommand("ON", LED_on); // Turns LED on
sCmd.addCommand("OFF", LED_off); // Turns LED off
sCmd.addCommand("getenv", getEnv);
sCmd.addCommand("relaybrd", relayBrd);
sCmd.addCommand("gettanklevel", getTankLevel);
sCmd.addCommand("setlouver", setLouver);
sCmd.addCommand("HELLO", sayHello); // Echos the string argument back
sCmd.addCommand("P", processCommand); // Converts two arguments to integers and echos them back
sCmd.setDefaultHandler(unrecognized); // Handler for command that isn't matched (says "What?")
Serial.println("Ready");
}
void loop() {
sCmd.readSerial(); // We don't do much, just process serial commands
// if (mySerial.available())
// Serial.write(mySerial.read());
// if (Serial.available())
// mySerial.write(Serial.read());
}
void relayBrd(){
char *arg;
char *arg1;
arg = sCmd.next();
arg1 = sCmd.next();
if (arg != NULL) {
//int num = atol(arg);
if (arg1 != NULL) {
int state = atol(arg1);
if (arg == "fan") {
//do something when var equals 1
registerWrite(1, state);
}else if(arg == "water"){
//do something when var equals 2
registerWrite(2, state);
}else if(arg == "mister"){
//do something when var equals 2
registerWrite(3, state);
}else if(arg == "heater"){
//do something when var equals 2
registerWrite(4, state);
}else{
// if nothing else matches, do the default
Serial.print("ERR got:");Serial.print(arg);Serial.println(":");
}
}else{
Serial.println("ERR Relay state missing 1/0");
}
}else{
Serial.println("ERR Relay argument missing fan/water/heater/mister");
}
}
// This method sends bits to the shift register:
void registerWrite(int whichPin, int whichState) {
Serial.print("Relay ");Serial.print(whichPin);Serial.print(" set to ");Serial.println(whichState);
// the bits you want to send
byte bitsToSend = 0;
// turn off the output so the pins don't light up
// while you're shifting bits:
digitalWrite(latchPin, LOW);
// turn on the next highest bit in bitsToSend:
bitWrite(bitsToSend, whichPin, whichState);
// shift the bits out:
shiftOut(dataPin, clockPin, MSBFIRST, bitsToSend);
// turn on the output so the LEDs can light up:
digitalWrite(latchPin, HIGH);
}
void getEnv(){
Serial.println("26 degC");
DHT22_ERROR_t errorCode;
Serial.print("Requesting data...");
errorCode = myDHT22.readData();
switch(errorCode)
{
case DHT_ERROR_NONE:
Serial.print("Got Data ");
Serial.print(myDHT22.getTemperatureC());
Serial.print("C ");
Serial.print(myDHT22.getHumidity());
Serial.println("%");
break;
default:
Serial.print("ERR DHT22 ");
Serial.println(errorCode);
}
}
void getTankLevel(){
Serial.println("78% water level");
sensorValue = analogRead( TANK_SENSOR );
constrainedValue = constrain( sensorValue, TANK_EMPTY, TANK_FULL );
tankLevel = map( constrainedValue, TANK_EMPTY, TANK_FULL, 0, 100 );
}
void setLouver() {
char *arg;
arg = sCmd.next();
if (arg != NULL) {
if(arg == "OPEN"){
Serial.println("Louver OPEN");
}else if(arg == "CLOSE"){
Serial.println("Louver CLOSED");
}else{
Serial.print(arg);Serial.println(" not known");
}
}else{
Serial.println("Louver command missing OPEN/CLOSE");
}
}
void LED_on() {
Serial.println("LED on");
digitalWrite(arduinoLED, HIGH);
}
void LED_off() {
Serial.println("LED off");
digitalWrite(arduinoLED, LOW);
}
void sayHello() {
char *arg;
arg = sCmd.next(); // Get the next argument from the SerialCommand object buffer
if (arg != NULL) { // As long as it existed, take it
if (arg == "HELLO") { // As long as it existed, take it
Serial.print("YES ");
Serial.println(arg);
}else{
Serial.print("NO ");
Serial.println(arg);
}
}
else {
Serial.println("Hello Pi");
}
}
void processCommand() {
int aNumber;
char *arg;
Serial.println("We're in processCommand");
arg = sCmd.next();
if (arg != NULL) {
aNumber = atoi(arg); // Converts a char string to an integer
Serial.print("First argument was: ");
Serial.println(aNumber);
}
else {
Serial.println("No arguments");
}
arg = sCmd.next();
if (arg != NULL) {
aNumber = atol(arg);
Serial.print("Second argument was: ");
Serial.println(aNumber);
}
else {
Serial.println("No second argument");
}
}
// This gets set as the default handler, and gets called when no other command matches.
void unrecognized(const char *command) {
Serial.println("What?");
}