SoftwareSerial library with ESP-01 and HC-12 together

Community General Discussion
1

Hello, could you please help me set up communication for HC-12 and ESP01 together on Arduino UNO?

My goal is to receive a message from HC-12 and send it to Thinspeak. I have the wiring correctly. The code below works for both receiving news from the HC-12 and sending a message to ThinkSpeak, but they do not work together.

ESP even initializes and connects to the wifi, then the HC-12 receives the message, but ESP can no longer send the message to the web. When I comment out the HC12.begin () line, sending to ThinkSpeak works without problems.

I read that the SoftwareSerial Library can work for multiple software serial ports, but only one can receive data at a time. So should I stop receiving HC-12 or ESP? How?

Thank you for your help.


  #include <SoftwareSerial.h>

  String MsgBuf = "";   
  unsigned long millisThinkSpeak = 0;
  
// HC-12
  SoftwareSerial HC12(3, 2);  
  #define pinSet 4
  
// ESP8266
  SoftwareSerial SerialESP(8,9); 
  int countTimeCommand;
  boolean found = false;

void setup() {
    Serial.begin(9600);
    
  //Begin ESP8266
    SerialESP.begin(115200);
    sendATtoESP("AT",5,"OK");
    sendATtoESP("AT+CWMODE=1",5,"OK");
    sendATtoESP("AT+CWJAP=\"XXXXXXXXXX\",\"XXXXXXXXXX\"",20,"OK");  

  //Begin HC-12
    pinMode(pinSet, OUTPUT); 
    digitalWrite(pinSet, HIGH); 
    delay(100);
    HC12.begin(9600);  
}

void loop(){
  unsigned long millisTime=millis();
 
  //HC-12
    while (HC12.available()) { 
      char MsgChar = HC12.read(); // read every byte
      MsgBuf += char(MsgChar); // byte to buffer
      if (MsgChar == '\n') { //if end of message do..

      Serial.println(MsgBuf);
      //decode Msg and save to variable
    
      MsgBuf = "";     
      }
    } 
    
 //ESP - ThinkSpeak every minute
  if (millisTime-millisThinkSpeak > 60000) {
    millisThinkSpeak=millisTime;
    
    SerialESP.flush();
    sendATtoESP("AT+CIPSTART=\"TCP\",\"184.106.153.149\",80", 10,"OK");
  
    String MsgTS = "GET /update?api_key=";
    MsgTS += "QM1DIPJTK8LEOP1Y";
    MsgTS +="&field1=";
    MsgTS += String ("10"); //variable from HC-12
    MsgTS += "\r\n\r\n";
    
    String SizeTS = "AT+CIPSEND=";
    SizeTS += MsgTS.length();
    sendATtoESP(SizeTS,10,"OK");
  
    if(SerialESP.find(">")){
      sendATtoESP(MsgTS,20,"OK");
      }
    else{
      Serial.println("Message don't send");
      sendATtoESP("AT+CIPCLOSE",5,"OK");
      }
  }   
}

void sendATtoESP(String command, int maxTime, char readReplay[]) {
  Serial.print("Command to ESP: ");
  Serial.print(command);
  Serial.print(" ");
  while(countTimeCommand < (maxTime*1)){
    SerialESP.println(command);//at+cipsend
    if(SerialESP.find(readReplay)){//ok
      found = true;
      break;
    }
    countTimeCommand++;
  }
  
  if(found == true)   {
    Serial.println("--OK--");
    countTimeCommand = 0;
  }
  if(found == false)  {
    Serial.println("--Fail--");
    countTimeCommand = 0;
  }  
  found = false;
}
2

it is usually a bad idea to try to use more than one SoftwareSerial port.

it seems though your communications are not simultaneous but could be consecutive - You could look at at that example for guidance

I would advise to wire the ESP to the hardware Serial port and not use the Serial Console anymore or get a better hardware (just use a more capable ESP as your main Arduino)

3

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