how to set up RGB leds on arduino ethernet with udp instruction? - arduino

Question

I'm working on a kind of traffic light with RGB LEDs. I try to take a udp value sent from a server to the arduino mega and ethernet shield, then the arduino should change the color of the LED.
Sadly until now, it does not work. In the serial monitor, I find out that the udp packet was received, but then the LED does not work. I was hoping that you guys can help me to figure out why my code isn't working. Thank you in advance! Here is my code:
/*
Web Server
*/
#include <SPI.h>
#include <Ethernet.h>
#include <EthernetUdp.h>
void Color(int R, int G, int B) //set up for the RGB led
{
analogWrite(3, R) ; // Rojo
analogWrite(5, G) ; // Green - Verde
analogWrite(6, B) ; // Blue - Azul
}
// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = {
0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED};
IPAddress ip(10, 90, 111, 150);
unsigned int localPort = 8888; // local port to listen on
// buffers for receiving and sending data
char packetBuffer[UDP_TX_PACKET_MAX_SIZE]; // buffer to hold incoming packet,
char ReplyBuffer[] = "acknowledged"; // a string to send back
// An EthernetUDP instance to let us send and receive packets over UDP
EthernetUDP Udp;
// Initialize the Ethernet server library
// with the IP address and port you want to use
// (port 80 is default for HTTP):
EthernetServer server(80);
void setup() { //seting up the outputs for the rgb
pinMode(3, OUTPUT);
pinMode(5, OUTPUT);
pinMode(6, OUTPUT);
// You can use Ethernet.init(pin) to configure the CS pin
//Ethernet.init(10); // Most Arduino shields
//Ethernet.init(5); // MKR ETH shield
//Ethernet.init(0); // Teensy 2.0
//Ethernet.init(20); // Teensy++ 2.0
//Ethernet.init(15); // ESP8266 with Adafruit Featherwing Ethernet
//Ethernet.init(33); // ESP32 with Adafruit Featherwing Ethernet
// start the Ethernet connection and the server:
Ethernet.begin(mac, ip);
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
Serial.println("Ethernet WebServer Example");
// Check for Ethernet hardware present
if (Ethernet.hardwareStatus() == EthernetNoHardware) {
Serial.println("Ethernet shield was not found. Sorry, can't run without hardware. :(");
while (true) {
delay(1); // do nothing, no point running without Ethernet hardware
}
}
if (Ethernet.linkStatus() == LinkOFF) {
Serial.println("Ethernet cable is not connected.");
}
// start the server
Udp.begin(localPort);
server.begin();
Serial.print("server is at ");
Serial.println(Ethernet.localIP());
}
void loop() {
// if there's data available, read a packet
int packetSize = Udp.parsePacket();
if (packetSize) {
Serial.print("Received packet of size ");
Serial.println(packetSize);
Serial.print("From ");
IPAddress remote = Udp.remoteIP();
for (int i=0; i < 4; i++) {
Serial.print(remote[i], DEC);
if (i < 3) {
Serial.print(".");
}
}
Serial.print(", port ");
Serial.println(Udp.remotePort());
// read the packet into packetBufffer
Udp.read(packetBuffer, UDP_TX_PACKET_MAX_SIZE);
Serial.println("Contents:");
Serial.println(packetBuffer);
// send a reply to the IP address and port that sent us the packet we received
Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());
Udp.write(ReplyBuffer);
Udp.endPacket();
}
char numero = packetBuffer;
if (numero = "1") Color(250, 0, 0) ;
if (numero = "2") Color(100, 110, 0);
if (numero = "3") Color(0, 255, 0);
delay(10);
}
From now, it just receives the udp, and while compiling I get:
warning: invalid conversion from 'const char*' to 'char' [-fpermissive]
but in the end, it compiles.
edited:
i changed the code in this way (just in the final part), and now when i send the udp packet, no matter what i send, i get the green light on, but only the green one, here is the code
void loop() {
// if there's data available, read a packet
int packetSize = Udp.parsePacket();
if (packetSize) {
Serial.print("Received packet of size ");
Serial.println(packetSize);
Serial.print("From ");
IPAddress remote = Udp.remoteIP();
for (int i=0; i < 4; i++) {
Serial.print(remote[i], DEC);
if (i < 3) {
Serial.print(".");
}
}
Serial.print(", port ");
Serial.println(Udp.remotePort());
// read the packet into packetBufffer
Udp.read(packetBuffer, UDP_TX_PACKET_MAX_SIZE);
Serial.println("Contents:");
Serial.println(packetBuffer);
char numero = packetBuffer;
if (numero = 'R') Color(250, 0, 0) ;
if (numero = 'A') Color(100, 100, 0);
if (numero = 'V') Color(0, 255, 0);
// send a reply to the IP address and port that sent us the packet we received
Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());
Udp.write(ReplyBuffer);
Udp.endPacket();
}

Answer 1

I'd recommend to find some C++ tutorial for starters.
Anyway:
char numero = packetBuffer; // wrong, you are assigning part of address to char, not character at that address...
if (numero = 'R') Color(250, 0, 0) ; // better but still wrong - numero is set to 'R' and it's also always true
if (numero = 'A') Color(100, 100, 0); // similar to previous
if (numero = 'V') Color(0, 255, 0); // and again
Correct version:
char numero = packetBuffer[0]; // get the first character in buffer
if (numero == 'R') Color(250, 0, 0) ; // compare numero with 'R'
if (numero == 'A') Color(100, 100, 0); // compare numero with 'A'
if (numero == 'V') Color(0, 255, 0); // ...
If there is nothing else wrong, that should fix it