How can I use IRsend with a string or convert a char from serial to uint32_t?

Arduino Asked by Johnny Derpp on December 13, 2020

I’m trying to control my arduino with a raspberry pi with python instead of C++ (which I don’t know). I’ve found code to take a string from serial and print it, but instead I’d like to use IRsend to use the code. Unfortunately I’m getting the error invalid conversion from ‘char*’ to ‘uint32_t {aka long unsigned int}’ [-fpermissive]. I know this must be an incredibly dumb question but is there a int() function for uint32_t for arduino C++? that I could set blah=uint32_t(buf) and then use my irsend.sendNEC(buf, 32)? If it’s not painfully obvious, I don’t know C++ and my python isn’t great.

#include <IRremote.h>

char buf[80];

int readline(int readch, char *buffer, int len) {
  static int pos = 0;
  int rpos;

  if (readch > 0) {
    switch (readch) {
      case 'r': // Ignore CR
      case 'n': // Return on new-line
        rpos = pos;
        pos = 0; // Reset position index ready for next time
        return rpos;
        if (pos < len-1) {
          buffer[pos++] = readch;
          buffer[pos] = 0;
  return 0;

void setup() {

IRsend irsend;

void loop() {
  if (readline(, buf, 80) > 0) {
    Serial.print("You entered: >");
    irsend.sendNEC(buf, 32);


/home/pi/Desktop/sendIRfromserial2addingir/sendIRfromserial2addingir.ino: 39:27: warning: invalid conversion from 'char*' to 'uint32_t {aka long unsigned int}' [-fpermissive]
             irsend.sendNEC(buf, 32);

In file included from

/home/pi/Arduino/libraries/IRremote/src/IRremote.h:444:10: note:   initializing argument 1 of 'void IRsend::sendNEC(uint32_t, uint8_t, bool)'
     void sendNEC(uint32_t data, uint8_t nbits, bool repeat = false);

One Answer

Instead of

irsend.sendNEC(buf, 32);

cast it to an unsigned int32 type:

irsend.sendNEC((uint32_t) buf, 32);

Correct answer by Michel Keijzers on December 13, 2020

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