RS232 to TTL converter help

[rhyzenn]

Good day to whoever is reading, I'm new to arduino and programming as a whole but I'm doing my first project which is an automatic attendance scanner that uses an Arduino nano. The scanner uses a RS232 port and that's what I used to connect to the arduino nano. The scanner works and it scans but what I see in the serial monitor is weird symbols that don't display anything, I'm assuming this is due to my mistake of connecting RS232 to arduino? How do you connect the RS232 port and the TTL converter? and what TTL converter do I use? any would do?

I'm sorry if my questions and explanation we're worded badly, I can explain further if needed. Thank you for taking time out of your day to read and answer this.

[lastchancename]

Confirm your scanner and Arduino code are using/set to the same bitrate.

[TomGeorge]

Hi, @rhyzenn
Welcome to the forum.

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Can you please post a link to specs/data of your scanner?
Can you please post your code?

Can you please post a copy of your circuit, a picture of a hand drawn circuit in jpg, png?
Hand drawn and photographed is perfectly acceptable.
Please include ALL hardware, power supplies, component names and pin labels.

If you Google;

arduino rs232 to tll converter

You will find many converters and YouTube and other instructions on how to connect them.

Google;

connecting arduino to rs232

Will also help.

Tom....

[rhyzenn]

Hello Tom, thank you for answering

Scanner's Specs:
Model: R26
Optical Resolution: 752*480 CMOS
Scanning Mode: Inductive Reading
Scanning Speed: 25cm/sec
Scanning Accuracy: ≥4mil
Maximum Power: 1.33W
Voltage: 3.3V to 5V plus or minus 5%
Maximum Current: 230mA
I can send the shoppee link if needed

The code I'm using I got online to see if the scanner works:

#include <SoftwareSerial.h>
SoftwareSerial mySerial(3, 4);
 
void setup()
{
  Serial.begin(9600);  
  mySerial.begin(9600); 
}
 
void loop()
{
  if (mySerial.available()) 
  {
    while (mySerial.available()) 
    {
      char input = mySerial.read();
      Serial.print(input); 
      delay(5);
    }
    Serial.println();
  }
}

Circuit, this is what I'm currently following

I'm using an arduino nano, the scanner I got from shopee, connector wire, a breadboard and my laptop. I have the latest version of Arduino IDE installed

The scanner description on shopee says that it uses 3.3 to 5V which falls in range to what an Arduino nano needs right? So why does it need an RS232? and why has the data I receive are all random symbols? I currently can't get a picture of my materials since they're at school and my arduino nano doesn't work anymore

I'll follow your advice for the RS232, sorry for all the questions and thank you again tom for answering them previously.

[TomGeorge]

Hi,
Is this your scanner?

MEFESE Embedded 1D 2D Barcode Scanner QR Bar Code Reader Module Scanner USB...

Where did you get the RS232 output info?
What speed is the output?

Thanks.. Tom....

[rhyzenn]

Yes that is it

@TomGeorge

Where did you get the RS232 output info?

I don't know what you mean by that, I assumed it used RS232 and I asked ai what it meant and if I should use it instead of Usb.

@TomGeorge

What speed is the output?

It should be 25cm/sec according to the specs if that's what you're asking. If it's the baud rate then I don't know, it doesn't specify

[kmin]

@rhyzenn

If it's the baud rate then I don't know, it doesn't specify

Should be 9600. According to manual found here, you don't even need RS232. You should be able to configure the scanner for 5V TTL output with jumper settings.

You find instructions here:
https://aliexpress.com/item/1005006809934051.html

[rhyzenn]

Thank you for the manual, the page on shopee doesn't have one

[jim-p]

@rhyzenn

So why does it need an RS232?

Because RS232 can be as high as 25V and that will damage the nano.

[rhyzenn]

I understand that but Arduino nano logic is up to 5v right? and the voltage of the scanner is 3.5 to 5v so I don't understand why it is still a RS232, but I don't need to use RS232 according to what kmin said

[bobcousins]

Your scanner has jumpers to set the type of interface, you need to know what those jumpers are set to.

[jim-p]

@rhyzenn

I understand that but Arduino nano logic is up to 5v right?

No I don't think you understand. RS232 can be as high as 25V and the Nano maximum I/O is ONLY 5V. If you connect more than 5V to a Nano you will damage it.
So you need an RS232 to TTL converter to convert the high voltage RS232 to 5V.

If the device you bought said RS232 then you need a converter.