Help reqd in 2d mapping of environment

Projects Programming
1

I wanted to create a 2d map of my environment in serial monitor using rplidar a1m8 arduino mega, where empty spaces are left as such and obstacles marked by some symbols ex: "*", tried this code but nothing is printed in serial monitor except "mapa". could anyone please guide me on this

#include <RPLidar.h>

RPLidar lidar;
#define RPLIDAR_MOTOR 3

#define mapa_SIZE_X 50
#define mapa_SIZE_Y 50

int mapa[mapa_SIZE_X][mapa_SIZE_Y];

void setup() {
  lidar.begin(Serial3);
  Serial.begin(115200);
  pinMode(RPLIDAR_MOTOR, OUTPUT);
  //lidar.setMotorPWM(255);
  lidar.startScan();
}

void loop() {
  if (IS_OK(lidar.waitPoint())) {
    float distance = lidar.getCurrentPoint().distance;
    float angle = lidar.getCurrentPoint().angle;

    // Convert polar coordinates to cartesian coordinates
    int x = int((distance / 10) * cos(angle));
    int y = int((distance / 10) * sin(angle));

    // mapa the cartesian coordinates to the mapa array
    int mapa_x = x + (mapa_SIZE_X / 2);
    int mapa_y = y + (mapa_SIZE_Y / 2);
    if (mapa_x >= 0 && mapa_x < mapa_SIZE_X && mapa_y >= 0 && mapa_y < mapa_SIZE_Y) {
      mapa[mapa_x][mapa_y] = 1;
    }
  }

  // Print out the mapa to the serial monitor
  Serial.println("mapa:");
  for (int y = mapa_SIZE_Y - 1; y >= 0; y--) {
    for (int x = 0; x < mapa_SIZE_X; x++) {
      if (mapa[x][y] == 1) {
        Serial.print("*");
      } else {
        Serial.print(" ");
      }
    }
    Serial.println();
  }
  Serial.println();

  delay(1000);
}

thanks in advance

circuit diagram

image
image821×503 96.8 KB

tx of rplidar to 15th pin of arduino mega
rx of rp lidar to 14th pin of arduino mega
vcc5v and 5v moto - to 5v supply
gnd, gnd moto to gnd supply
ctrl_moto to 3rd pin of arduino mega

2

To see if the LIDAR is actually working, put in some Serial.print statements to see distance measurements.

For example:

    float distance = lidar.getCurrentPoint().distance;
    float angle = lidar.getCurrentPoint().angle;
   Serial.print(" d = ");
   Serial.println(distance);
3

If any element of this equation is zero, mapa[x][y] will be zero (to get a "*", mapa[x][y] must be greater than zero).

    int x = int((distance / 10) * cos(angle));
    int y = int((distance / 10) * sin(angle));
4

i dont understand how to implement, can you explain me in more details, do you mean to say there is issue with this code over here??

int x = int((distance / 10) * cos(angle));
    int y = int((distance / 10) * sin(angle));
5

If angle is zero, the equation equals zero.

If sin(angle) or cos(angle) equals zero, the equation equals zero.

If distance is less than 10, the equation equals zero.

Serial.print() the values of angle, sin(angle), cos(angle) and distance.

6

I guess the problem lies here because i tried executing this code, and spits it some random data

#include <RPLidar.h>

// You need to create an driver instance 
RPLidar lidar;

#define RPLIDAR_MOTOR 3 // The PWM pin for control the speed of RPLIDAR's motor.
                        // This pin should connected with the RPLIDAR's MOTOCTRL signal 
                       
                        
void setup() {
  // bind the RPLIDAR driver to the arduino hardware serial
  lidar.begin(Serial3);
  Serial.begin(115200);
  
  // set pin modes
  pinMode(RPLIDAR_MOTOR, OUTPUT);
}

void loop() {
  if (IS_OK(lidar.waitPoint())) {
    float distance = lidar.getCurrentPoint().distance; //distance value in mm unit
    float angle    = lidar.getCurrentPoint().angle; //anglue value in degree
    bool  startBit = lidar.getCurrentPoint().startBit; //whether this point is belong to a new scan
    byte  quality  = lidar.getCurrentPoint().quality; //quality of the current measurement
    
    //perform data processing here... 
    Serial.print("distance"); Serial.println(distance/10);
    Serial.print("angle");  Serial.println(angle/10);
    
    
  } else {
    analogWrite(RPLIDAR_MOTOR, 0); //stop the rplidar motor
    
    // try to detect RPLIDAR... 
    rplidar_response_device_info_t info;
    if (IS_OK(lidar.getDeviceInfo(info, 100))) {
       // detected...
       lidar.startScan();
       
       // start motor rotating at max allowed speed
       analogWrite(RPLIDAR_MOTOR, 255);
       delay(1000);
    }
  }
}

output it gives is this

New Line

115200 baud

11:37:33.182 -> angle30.31

11:37:33.182 -> distance1025.55

11:37:33.182 -> angle3.16

11:37:33.182 -> distance0.00

11:37:33.182 -> angle31.47

11:37:33.182 -> distance4.00

11:37:33.182 -> angle30.60

11:37:33.182 -> distance60.38

11:37:33.182 -> angle32.24

11:37:33.182 -> distance115.20

11:37:33.279 -> angle32.64

11:37:33.279 -> distance1065.07

11:37:33.279 -> angle32.90

11:37:33.279 -> distance198.40
``` what might be the issue, connections are same as i have given in my first post?
i too guess, problem is with data that is given by lidar
7

It seems the LIDAR is detecting the vehicle (distances 4.00 to 0.00 ??cm??) but getting the angle wrong.

Put the LIDAR in a box, preferably circular, with the LIDAR xcvr at the center of the box (without the vehicle?). Readings should return equal. If equal, put a brick in the box to see ang/dist of the brick.

Is there a way to adjust the reading of the return or the moment of the transmit?

Dronebotworkshop made a video on LIDAR and the RPLIDAR that you have...

8

I think this line:

lidar.begin(Serial3);

Read like this:

lidar.begin(Serial);</s>

Then disconnect the USB cable and power the Arduino externally.

edit: Sorry, see next post. I did not pay attention to using the Mega2560, which has more ports.
19(RX), 18(TX)
17(RX), 16(TX)
15(RX), 14(TX)
0(RX), 1(TX)

9

Ignore the above suggestion, if you are using Serial3 on the Mega2560.

Double check that you have connected TX on the RPLidar to D15 (RX3) and RX on the RPLidar to D14 (TX3).

10

fyi, this is the older version of rplidar, I am having new version, actually, for which I have attached the datasheet of it

11

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