A solution was using conditionals inside the arduino loop() to make the servos move. Another problem was communicating with the PC: took us some time to figure out that the string being sent through the serial port should have a fixed length, therefore adding leading zeros to the angles and the sensor values solved the problem.
- Lidar Scanner Schematic.png (36.47 KiB) Viewed 1098 times
- Arduino Uno R3 USB Microcontroller
- LIDAR-Lite 3 Laser Rangefinder
- Lynxmotion Pan and Tilt Kit
- LCD Keypad Shield Arduino Compatible
- Cytron Arduino Proto Shield
- Wall Adapter Power Supply 7.5VDC 1A
- Electrolytic Capacitor Pack 1000uF/25V
- LM78M05CT 5V 0.5A Voltage Regulator
- 2.1mm Barrel Jack Adapter
Code: Select all
// LidarScanner.pde Processing sketch
// Load sketch into Processing, available from:
// https://processing.org/
// This sketch accepts XYZ coordinates from Arduino LIDAR scanner
// and displays them graphically as a 3D point cloud that you can
// pan, zoom, and rotate using keyboard.
import processing.serial.*;
Serial serial;
int serialPortNumber = 0;
float angle = 6.5f;
float angleIncrement = 0;
float xOffset = 3.0;
float xOffsetIncrement = 0;
float yOffset = 152.0f;
float yOffsetIncrement = 0;
float scale = 2.6f;
float scaleIncrement = 0;
ArrayList<PVector> vectors;
int lastPointIndex = 0;
int lastPointCount = 0;
void setup() {
size(800, 600, P3D);
colorMode(RGB, 255, 255, 255);
noSmooth();
vectors = new ArrayList<PVector>();
String[] serialPorts = Serial.list();
String serialPort = serialPorts[serialPortNumber];
println("Using serial port \"" + serialPort + "\"");
println("To use a different serial port, change serialPortNumber:");
printArray(serialPorts);
serial = new Serial(this, serialPort, 9600);
}
void draw() {
String input = serial.readStringUntil(10);
if (input != null) {
String[] components = split(input, ' ');
if (components.length == 3) {
vectors.add(new PVector(float(components[0]), float(components[1]), float(components[2])));
}
}
background(0);
translate(width/2, height/2, -50);
rotateY(angle);
int size = vectors.size();
for (int index = 0; index < size; index++) {
PVector v = vectors.get(index);
if (index == size - 1) {
// draw red line to show recently added LIDAR scan point
if (index == lastPointIndex) {
lastPointCount++;
} else {
lastPointIndex = index;
lastPointCount = 0;
}
if (lastPointCount < 10) {
stroke(255, 0, 0);
line(xOffset, yOffset, 0, v.x * scale + xOffset, -v.z * scale + yOffset, -v.y * scale);
}
}
stroke(255, 255, 255);
point(v.x * scale + xOffset, -v.z * scale + yOffset, -v.y * scale);
}
angle += angleIncrement;
xOffset += xOffsetIncrement;
yOffset += yOffsetIncrement;
scale += scaleIncrement;
}
void keyPressed() {
if (key == 'q') {
// zoom in
scaleIncrement = 0.02f;
} else if (key == 'z') {
// zoom out
scaleIncrement = -0.02f;
} else if (key == 'a') {
// move left
xOffsetIncrement = -1f;
} else if (key == 'd') {
// move right
xOffsetIncrement = 1f;
} else if (key == 'w') {
// move up
yOffsetIncrement = -1f;
} else if (key == 's') {
// move down
yOffsetIncrement = 1f;
} else if (key =='x') {
// erase all points
vectors.clear();
} else if (key == CODED) {
if (keyCode == LEFT) {
// rotate left
angleIncrement = -0.015f;
} else if (keyCode == RIGHT) {
// rotate right
angleIncrement = 0.015f;
}
}
}
void keyReleased() {
if (key == 'q') {
scaleIncrement = 0f;
} else if (key == 'z') {
scaleIncrement = 0f;
} else if (key == 'a') {
xOffsetIncrement = 0f;
} else if (key == 'd') {
xOffsetIncrement = 0f;
} else if (key == 'w') {
yOffsetIncrement = 0f;
} else if (key == 's') {
yOffsetIncrement = 0f;
} else if (key == CODED) {
if (keyCode == LEFT) {
angleIncrement = 0f;
} else if (keyCode == RIGHT) {
angleIncrement = 0f;
}
}
}
Code: Select all
// LidarScanner.ino Arduino sketch
// Load sketch into Arduino software, available from:
// https://www.arduino.cc/
// This sketch controls X and Y servos to pan/tilt a LIDAR detector,
// either manually (by pressing LCD buttons to control XY location),
// or automatically (scanning horizontally and vertically).
// XYZ coordinates are output to the serial port to be received and
// displayed on computer by LidarScanner.pde Processing sketch.
// This sketch requires library "LIDAR-Lite v3" by Garmin.
// Select menu "Sketch", "Include Library", "Manage Libraries...",
// and in textbox "Filter your search...", enter "lidar".
// Freetronics LCD shield uses D3 to control backlight brightness,
// but digital output needed for servo control, so disable the
// backlight control by cutting strap marked "D3" on LCD shield.
#include <Servo.h>
#include <LIDARLite.h>
#include <LiquidCrystal.h>
Servo servoX;
Servo servoY;
LIDARLite lidar;
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);
// Minimum and maximum servo angle in degrees
// Modify to avoid hitting limits imposed by pan/tilt bracket geometry
int minPosX = 0;
int maxPosX = 180;
int minPosY = 26;
int maxPosY = 125;
int buttonPin = A0;
int buttonValue = 0;
int buttonThreshold = 50;
int lastPosX = 0;
int lastPosY = 0;
int loopCount = 0;
int radius = 0;
int lastRadius = 0;
boolean selectButtonPressed = false;
boolean scanning = false;
boolean scanDirection = false;
int scanIncrement = 1;
int posX = (maxPosX + minPosX) / 2;
int posY = (maxPosY + minPosY) / 4;
float pi = 3.14159265;
float deg2rad = pi / 180.0;
void setup() {
lcd.begin(16, 2);
updateModeDisplay();
lidar.begin(0, true);
lidar.configure(0);
servoX.attach(2);
servoY.attach(3);
servoX.write(posX);
servoY.write(posY);
Serial.begin(9600);
}
void loop() {
buttonValue = analogRead(buttonPin);
if (scanning) {
if (abs(buttonValue - 741) < buttonThreshold) {
if (!selectButtonPressed) {
// switch to manual scan mode
selectButtonPressed = true;
scanning = false;
updateModeDisplay();
}
} else {
selectButtonPressed = false;
}
if (scanDirection) {
posX += scanIncrement;
} else {
posX -= scanIncrement;
}
if (posX > maxPosX || posX < minPosX) {
// hit limit X limit, reverse auto scan direction
scanDirection = !scanDirection;
posY += scanIncrement;
if (posY > maxPosY) {
// completed auto scan, return to manual scan mode
scanning = false;
updateModeDisplay();
}
}
} else {
if (abs(buttonValue - 741) < buttonThreshold) {
if (!selectButtonPressed) {
// switch to auto scan mode
selectButtonPressed = true;
scanning = true;
posX = minPosX;
posY = minPosY;
scanDirection = true;
updateModeDisplay();
}
} else if (abs(buttonValue - 505) < buttonThreshold) {
// manual scan left
posX += 1;
} else if (abs(buttonValue - 329) < buttonThreshold) {
// manual scan down
posY -= 1;
} else if (abs(buttonValue - 145) < buttonThreshold) {
// manual scan up
posY += 1;
} else if (abs(buttonValue - 0) < buttonThreshold) {
// manual scan right
posX -= 1;
} else {
selectButtonPressed = false;
}
}
posX = min(max(posX, minPosX), maxPosX);
posY = min(max(posY, minPosY), maxPosY);
bool moved = moveServos();
displayPosition();
loopCount += 1;
if (loopCount % 100 == 0) {
// recalibrate scanner every 100 scans
radius = lidar.distance();
} else {
radius = lidar.distance(false);
}
if (abs(radius - lastRadius) > 2)
{
lastRadius = radius;
lcd.setCursor(8, 0);
lcd.print("D:" + String(radius / 100.0, 2) + " ");
}
if (scanning || moved) {
float azimuth = posX * deg2rad;
float elevation = (180 - maxPosY + posY) * deg2rad;
double x = radius * sin(elevation) * cos(azimuth);
double y = radius * sin(elevation) * sin(azimuth);
double z = radius * cos(elevation);
Serial.println(String(-x, 5) + " " + String(y, 5) + " " + String(-z, 5));
}
}
bool moveServos()
{
bool moved = false;
static int lastPosX;
static int lastPosY;
int delta = 0;
if (posX != lastPosX) {
delta += abs(posX - lastPosX);
servoX.write(posX);
lastPosX = posX;
moved = true;
}
if (posY != lastPosY) {
delta += abs(posY - lastPosY);
servoY.write(posY);
lastPosY = posY;
moved = true;
}
delay(30);
return moved;
}
void displayPosition()
{
static int lastPosX;
static int lastPosY;
if (posX != lastPosX) {
lcd.setCursor(0, 0);
lcd.print("X:" + String(posX) + " ");
lastPosX = posX;
}
if (posY != lastPosY) {
lcd.setCursor(0, 1);
lcd.print("Y:" + String(posY) + " ");
lastPosY = posY;
}
}
void updateModeDisplay()
{
lcd.setCursor(8, 1);
if (scanning) {
lcd.print("Scanning");
} else {
lcd.print("Manual ");
}
}