Newbie at reading serial data from LRF

Using Arduino Sensors
#1

I'm currently using an Opti-Logic RS400 Laser Range Finder along with an Arduino MEGA 2560 for a project. I've been trying to read the serial data using code I've found online, but what I get back is gibberish because I don't know how to properly filter or convert the data. I've tried using simple serial reading code like this:

String readString;

void setup() {
      Serial.begin(9600);
      Serial2.begin(19200);
      Serial.println("Serial Test");
        }

void loop() {

      while (Serial2.available()) {
        delay(100);  
        if (Serial2.available() >0) {
          readString = Serial2.read();
          readString += c;}
      }
        
      if (readString.length() >0) {
      Serial.println(readString);
      
      readString="";
      } 
   }

However, this is what I receive in the serial monitor:

Serial Test
?}-¥g!1-9¿[Y???¿[=#153-#75e¿S5e?£?åë'!5¿?¿

When I need to receive something like:

Serial Test
DIST:0046.61F
DIST:0046.42F
DIST:0046.25F

The lrf uses RS-232 serial, and I thought this data could be readily converted with Arduino into string form, but I must be missing several steps. I set the Baud rate to 19200 which is under the specs, but the sensor is a little odd in that the instructions ask me to use HyperTerminal in Windows with specific settings to operate it through Windows. What vital step am I missing?

#2

RS232 uses different logic levels than TTL Serial. You need a conversion, like the MAX232 chip. Google it.

#3

So all the serial input/outputs on the Arduino are default TTL serial? Thanks, hopefully this will give me some readable data.

I also had some sensors that might be 3.3V(?), do I need some kind of converters to make them 5V even though they're TTL? Sorry if messed up some of the jargon, I'm extremely new to this.

#4

3.3V is sometimes called LVTTL (Low Voltage TTL). If you are talking Serial signals you are in luck. since 3.3V is well above the minimum required for a TTL '1' signal. You can safely connect a 3.3V TTL output to a 5V TTL input. The other way around depends on if your 3.3V input is "5V Tolerant". If not, you can use a voltage divider to bring the 5V signal down to 3.3V:

5V Output ----////-----3.3V Input-----////----Ground
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#5

Thanks again for the advice. I picked up an RS232 shifter, and I'm finally receiving the correct data on my computer. Wish I could upvote you for the help; saved me from experiencing a lot of headaches.

#6