Problems with RFID conversion from 3.3V TTL to 5V TTL

Other Hardware Sensors
1

I am new to the Arduino world. I have an Arduino R4 WiFi and I have connected an RFID sensor (see the specifications in the attached image). The problem is that the sensor’s TTL communication in RX is 3.3V, and Arduino, if I remember correctly, communicates at 5V. Indeed, I can’t see the incoming signal even though the sensor works because as soon as an RFID tag is detected, the LED lights up. I also purchased a logic level TXS0108E, but I don’t know if it’s useful for converting the signal. Can you help me?
Thanks

134 AGV user manual 5V.pdf (386,5 KB)

2

This is as simple as you can do

image
image837×632 5.94 KB

3

So, if I connect the TX pin to, for example, the RX pin 0 of the Arduino R4, is it able to accept TTL 3.3V input voltages?

4

Yes but don't use pins 0 and 1 on the R4. Use Software Serial
It may or may not work with 3.3V input but it won't damage anything. It's worth a try before you decide to do something more complicated.

5

I understand, but unfortunately, I don’t understand why it seems to work on Arduino UNO, as I get a result from this code:

#include <SoftwareSerial.h>
const int rxPin = 10; // Pin RX 
const int txPin = 11; // Pin TX 

SoftwareSerial mySerial(rxPin, txPin);

void setup() {
  Serial.begin(9600);
  mySerial.begin(9600);
}

void loop() {
  if (mySerial.available() > 0) {
    char receivedChar = mySerial.read();

    Serial.print("Dato ricevuto: ");
    Serial.println(receivedChar);
  }
}

However, with the R4 UNO configured the same way, this code doesn’t return anything.

6

The R4 is quite different. You do use pins 0 and 1. You do not use software serial but use Serial1 in your code. Seria1 is a hardware serial port.

7

This is why it works, you are doing a software serial port. Its top end is about 9600 baud simplex mode.

8

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