使用Arduino读取LeddarVu8激光雷达数据时串口输出乱码求助

Hey there, those question marks popping up in your Serial Monitor are a classic sign of communication breakdown between your Arduino and the LeddarVu8. Let’s walk through the most likely culprits and how to fix them:

1. Serial Baud Rate Mismatch #

This is the simplest and most common issue. Your code initializes the Leddar module at 115200 baud, but if your Arduino Serial Monitor is set to a different rate (like the default 9600), the incoming data will be garbled into question marks.

• Fix: Open the Serial Monitor, click the baud rate dropdown menu, and select 115200 to match your code's configuration.

2. Missing RS485 Transceiver Control (DE/RE Pins) #

RS485 is a half-duplex protocol—you need to explicitly toggle the transceiver between transmit and receive modes using the DE (Driver Enable) and RE (Receiver Enable) pins on your RS485 board. Your current code doesn’t handle this at all, which is probably a major cause of failed communication.

• How to fix:
  1. Connect the DE and RE pins of your RS485 board to a free digital pin on your Arduino (most modules tie these two pins together, so one pin controls both—let’s use pin 2 for this example).
  2. Modify your code to toggle this pin during send/receive cycles:

     #include <Leddar.h> // Use standard library path instead of absolute Windows path
     
     Leddar16 Leddar1(115200, 1); // Baudrate = 115200, Modbus slave ID = 01
     const int rs485ControlPin = 2; // Pin tied to DE/RE on RS485 module
     
     void setup() {
       pinMode(rs485ControlPin, OUTPUT);
       digitalWrite(rs485ControlPin, LOW); // Start in receive mode
       Leddar1.init();
     }
     
     void loop() {
       // Switch to receive mode before requesting detections from Leddar
       digitalWrite(rs485ControlPin, LOW);
       char result = Leddar1.getDetections();
       
       if (result >= 0) {
         // Switch to transmit mode to send data to Serial Monitor
         digitalWrite(rs485ControlPin, HIGH);
         for (int i = 0; i < Leddar1.NbDet; i++) {
           Serial.print("Segment: ");
           Serial.print(Leddar1.Detections[i].Segment);
           Serial.print(" Distance: ");
           Serial.print(Leddar1.Detections[i].Distance);
           Serial.print("\n");
         }
         digitalWrite(rs485ControlPin, LOW); // Switch back to receive mode
       } else {
         digitalWrite(rs485ControlPin, HIGH);
         Serial.print("Error: ");
         Serial.print((int)result);
         Serial.print("\n");
         digitalWrite(rs485ControlPin, LOW);
       }
       delay(50);
     }
     

3. Incorrect RS485 Wiring #

If you’ve swapped the A and B lines between your RS485 board and the LeddarVu8, communication will fail entirely, leading to garbled data.

• Fix: Double-check that the A pin on your RS485 module connects to the A pin on the LeddarVu8, and B to B. Some modules label these as D+/D- instead—remember: D+ = A, D- = B.

4. Library Path Issue #

Your code uses an absolute Windows path for the Leddar library (#include "C:\Program Files (x86)\Arduino\libraries\Leddar.h"). This can cause issues if the library isn’t installed in the standard Arduino libraries folder, or if you switch to a different OS later.

• Fix: Replace that line with #include <Leddar.h>—this tells Arduino to look in its standard library directories, which is the correct approach as long as you’ve installed the LeddarSDK properly.

5. Power Supply Problems #

The LeddarVu8 may not be getting enough power from the Arduino’s 5V pin. Laser radar modules can draw more current than the Arduino can reliably provide, leading to unstable communication.

• Fix: Power the LeddarVu8 using an external 5V power supply that meets its current requirements (check the module’s datasheet) instead of relying on the Arduino’s power output.

6. Modbus Slave ID Mismatch #

Your code initializes the Leddar with a slave ID of 1 (Leddar16 Leddar1(115200,1);). If the LeddarVu8’s default Modbus slave ID isn’t 1, communication won’t work.

• Fix: Check the LeddarVu8’s documentation to confirm its default ID, or use the official Leddar configuration tool to set it to 1 to match your code.

内容的提问来源于stack exchange，提问作者Ramah Wart