XV_Lidar_Controller.ino

/*
  XV Lidar Controller v1.4.0

  Copyright 2014-2016 James LeRoy getSurreal
  https://github.com/getSurreal/XV_Lidar_Controller
  http://www.getsurreal.com/products/xv-lidar-controller

  Contributions by:
    Doug Hilton mailto: six.speed (at) yahoo (dot) com

  See README for additional information

  The F() macro in the Serial statements tells the compiler to keep your strings in PROGMEM
*/
#include "TimerThree.h"                   // used for ultrasonic PWM motor control
#include "PID.h"
#include "EEPROM.h"
#include "EEPROMAnything.h"
#include "SerialCommand.h"

const int N_ANGLES = 360;                // # of angles (0..359)
const int SHOW_ALL_ANGLES = N_ANGLES;    // value means 'display all angle data, 0..359'

struct EEPROM_Config {
  byte id;
  char version[6];
  int motor_pwm_pin;            // pin connected to mosfet for motor speed control
  double rpm_setpoint;          // desired RPM (uses double to be compatible with PID library)
  double rpm_min;
  double rpm_max;
  double pwm_max;              // max analog value.  probably never needs to change from 1023
  double pwm_min;              // min analog pulse value to spin the motor
  int sample_time;             // how often to calculate the PID values

  // PID tuning values
  double Kp;
  double Ki;
  double Kd;

  boolean motor_enable;        // to spin the laser or not.  No data when not spinning
  boolean raw_data;            // to retransmit the seiral data to the USB port
  boolean show_dist;           // controlled by ShowDist and HideDist commands
  boolean show_rpm;            // controlled by ShowRPM and HideRPM commands
  boolean show_interval;       // true = show time interval, once per revolution, at angle=0
  boolean show_errors;         // Show CRC, signal strength and invalid data errors
  boolean aryAngles[N_ANGLES]; // array of angles to display
}
xv_config;

const byte EEPROM_ID = 0x07;   // used to validate EEPROM initialized

double pwm_val = 500;          // start with ~50% power
double pwm_last;
double motor_rpm;
unsigned long now;
unsigned long motor_check_timer = millis();
unsigned long motor_check_interval = 200;
unsigned int rpm_err_thresh = 10;  // 2 seconds (10 * 200ms) to shutdown motor with improper RPM and high voltage
unsigned int rpm_err = 0;
unsigned long curMillis;
unsigned long lastMillis = millis();

const unsigned char COMMAND = 0xFA;        // Start of new packet
const int INDEX_LO = 0xA0;                 // lowest index value
const int INDEX_HI = 0xF9;                 // highest index value

const int N_DATA_QUADS = 4;                // there are 4 groups of data elements
const int N_ELEMENTS_PER_QUAD = 4;         // viz., 0=distance LSB; 1=distance MSB; 2=sig LSB; 3=sig MSB

// Offsets to bytes within 'Packet'
const int OFFSET_TO_START = 0;
const int OFFSET_TO_INDEX = OFFSET_TO_START + 1;
const int OFFSET_TO_SPEED_LSB = OFFSET_TO_INDEX + 1;
const int OFFSET_TO_SPEED_MSB = OFFSET_TO_SPEED_LSB + 1;
const int OFFSET_TO_4_DATA_READINGS = OFFSET_TO_SPEED_MSB + 1;
const int OFFSET_TO_CRC_L = OFFSET_TO_4_DATA_READINGS + (N_DATA_QUADS * N_ELEMENTS_PER_QUAD);
const int OFFSET_TO_CRC_M = OFFSET_TO_CRC_L + 1;
const int PACKET_LENGTH = OFFSET_TO_CRC_M + 1;  // length of a complete packet
// Offsets to the (4) elements of each of the (4) data quads
const int OFFSET_DATA_DISTANCE_LSB = 0;
const int OFFSET_DATA_DISTANCE_MSB = OFFSET_DATA_DISTANCE_LSB + 1;
const int OFFSET_DATA_SIGNAL_LSB = OFFSET_DATA_DISTANCE_MSB + 1;
const int OFFSET_DATA_SIGNAL_MSB = OFFSET_DATA_SIGNAL_LSB + 1;

int Packet[PACKET_LENGTH];                 // an input packet
int ixPacket = 0;                          // index into 'Packet' array
const int VALID_PACKET = 0;
const int INVALID_PACKET = VALID_PACKET + 1;
const byte INVALID_DATA_FLAG = (1 << 7);   // Mask for byte 1 of each data quad "Invalid data"



/* REF: https://github.com/Xevel/NXV11/wiki
  The bit 7 of byte 1 seems to indicate that the distance could not be calculated.
  It's interesting to see that when this bit is set, the second byte is always 80, and the values of the first byte seem to be
  only 02, 03, 21, 25, 35 or 50... When it's 21, then the whole block is 21 80 XX XX, but for all the other values it's the
  data block is YY 80 00 00 maybe it's a code to say what type of error ? (35 is preponderant, 21 seems to be when the beam is
  interrupted by the supports of the cover) .
*/
const byte STRENGTH_WARNING_FLAG = (1 << 6);  // Mask for byte 1 of each data quat "Strength Warning"
/*
  The bit 6 of byte 1 is a warning when the reported strength is greatly inferior to what is expected at this distance.
  This may happen when the material has a low reflectance (black material...), or when the dot does not have the expected
  size or shape (porous material, transparent fabric, grid, edge of an object...), or maybe when there are parasitic
  reflections (glass... ).
*/
const byte BAD_DATA_MASK = (INVALID_DATA_FLAG | STRENGTH_WARNING_FLAG);

const byte eState_Find_COMMAND = 0;                        // 1st state: find 0xFA (COMMAND) in input stream
const byte eState_Build_Packet = eState_Find_COMMAND + 1;  // 2nd state: build the packet
int eState = eState_Find_COMMAND;
PID rpmPID(&motor_rpm, &pwm_val, &xv_config.rpm_setpoint, xv_config.Kp, xv_config.Ki, xv_config.Kd, DIRECT);

uint8_t inByte = 0;  // incoming serial byte
uint8_t motor_rph_high_byte = 0;
uint8_t motor_rph_low_byte = 0;
uint16_t aryDist[N_DATA_QUADS] = {0, 0, 0, 0};   // thre are (4) distances, one for each data quad
// so the maximum distance is 16383 mm (0x3FFF)
uint16_t aryQuality[N_DATA_QUADS] = {0, 0, 0, 0}; // same with 'quality'
uint16_t motor_rph = 0;
uint16_t startingAngle = 0;                      // the first scan angle (of group of 4, based on 'index'), in degrees (0..359)

SerialCommand sCmd;

boolean ledState = LOW;

#if defined(__AVR_ATmega2560__)  // if arduino mega 2560
const int ledPin = LED_BUILTIN;

#elif defined(__AVR_ATmega32U4__) && defined(CORE_TEENSY)  // if Teensy 2.0
const int ledPin = 11;

#elif defined(__AVR_ATmega32U4__)  // if Leonardo (no LED for Pro Micro)
const int ledPin = 13;

#elif defined(__MK20DX256__)  // if Teensy 3.1
const int ledPin = 13;

#elif defined(__MKL26Z64__)  // if Teensy LC
const int ledPin = 13;
#endif

// initialization (before 'loop')
void setup() {
  EEPROM_readAnything(0, xv_config);
  if ( xv_config.id != EEPROM_ID) { // verify EEPROM values have been initialized
    initEEPROM();
  }
  pinMode(xv_config.motor_pwm_pin, OUTPUT);
  Serial.begin(115200);                    // USB serial
#if defined(__AVR_ATmega2560__)            // if arduino mega 2560
  Serial1.begin(115200);                   // XV LDS data
#elif defined(__AVR_ATmega32U4__)
  Serial1.begin(115200);                   // XV LDS data
#elif defined(__MK20DX256__)               // if Teensy 3.1
  Serial1.begin(115200);                   // XV LDS data
#elif defined(__MKL26Z64__)                // if Teensy LC
  Serial1.begin(115200);                   // XV LDS data
#endif

  Timer3.initialize(30);                           // set PWM frequency to 32.768kHz

  rpmPID.SetOutputLimits(xv_config.pwm_min, xv_config.pwm_max);
  rpmPID.SetSampleTime(xv_config.sample_time);
  rpmPID.SetTunings(xv_config.Kp, xv_config.Ki, xv_config.Kd);
  rpmPID.SetMode(AUTOMATIC);

  initSerialCommands();
  pinMode(ledPin, OUTPUT);

  eState = eState_Find_COMMAND;
  for (ixPacket = 0; ixPacket < PACKET_LENGTH; ixPacket++)  // Initialize
    Packet[ixPacket] = 0;
  ixPacket = 0;
}

void loop() {
  byte aryInvalidDataFlag[N_DATA_QUADS] = {0, 0, 0, 0}; // non-zero = INVALID_DATA_FLAG or STRENGTH_WARNING_FLAG is set

  sCmd.readSerial();  // check for incoming serial commands
  if (Serial1.available() > 0) {                  // read byte from LIDAR and relay to USB
    inByte = Serial1.read();                      // get incoming byte:
    if (xv_config.raw_data)
      Serial.write(inByte);                 // relay

    // Switch, based on 'eState':
    // State 1: We're scanning for 0xFA (COMMAND) in the input stream
    // State 2: Build a complete data packet
    if (eState == eState_Find_COMMAND) {          // flush input until we get COMMAND byte
      if (inByte == COMMAND) {
        eState++;                                 // switch to 'build a packet' state
        Packet[ixPacket++] = inByte;              // store 1st byte of data into 'Packet'
      }
    }
    else {                                            // eState == eState_Build_Packet
      Packet[ixPacket++] = inByte;                    // keep storing input into 'Packet'
      if (ixPacket == PACKET_LENGTH) {                // we've got all the input bytes, so we're done building this packet
        if (eValidatePacket() == VALID_PACKET) {      // Check packet CRC
          startingAngle = processIndex();             // get the starting angle of this group (of 4), e.g., 0, 4, 8, 12, ...
          processSpeed();                             // process the speed