Published April 6, 2021 © GPL3+

Arduino Omnidirectional Car

Created an omnidirectional car that is powered by Arduino and controlled by a PS2 controller.

IntermediateShowcase (no instructions)8,862

Things used in this project

Hardware components

Arduino UNO

Adafruit Motor Shield V2

EMOZNY Mecanum Wheel Robot Kit

Screw Terminal Breakout Shield

Ultrasonic Sensor - HC-SR04 (Generic)

PS2 wireless remote and reciever

Chassis expansion plate

Adafruit 6 X AA battery holder with 5.5mm/2.1mm plug

Adafruit In-line power switch for 2.1mm barrel jack

Piezo buzzer

LED (generic)

Resistor 220 ohm

Software apps and online services

Arduino IDE

Hand tools and fabrication machines

Premium Female/Male Extension Jumper Wires, 40 x 6" (150mm)

10 Pc. Jumper Wire Kit, 5 cm Long

Soldering iron (generic)

Solder Wire, Lead Free

Story

Overview

In this project I will be showing the process I used to build and control an omnidirectional car, utilizing mecanum wheels. The car will be controlled by a wireless PS2 controller and includes LEDs for speed indication, a small piezo horn, and HC-SR04 sensors for object detection.

The Chassis

The chassis that I used was sold as a set (EMOZY mecanum wheel robot kit) and purchased on amazon.

https://www.amazon.com/gp/product/B084TNLFYB/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

Amazon picture of EMOZY mecanum wheel robot kit

This included:

Four mecanum wheels
Four DC motors with gear boxes
two chassis plates
standoffs

However it would be fairly easy to gather up the parts yourself, Adafruit sells very similar motors and gearboxes. https://www.adafruit.com/product/3777?gclid=CjwKCAjw3pWDBhB3EiwAV1c5rL1RGF34Q7nhI7VxfHFl_O1uBoj4WpKY2oM6noQD6oa1QQxTx2HJmxoCy1kQAvD_BwE

As well as the mecanum wheels https://www.adafruit.com/product/4678

Just make sure the wheels will work with the motors that you purchase. The chassis plates may be a little harder to come by. I bought a chassis plate for the top of the car from https://www.pololu.com/. They may have something that works.

Assembly

I would first recommend soldering the motor leads on if your motor does not come with them. It doesn't matter which lead goes where, just make sure the leads are long enough for your use case. If you are using the chassis kit it is fairly easy to assemble by following the directions. Just remember that the wheels need to go on a certain way, two of the wheels are for the right side and two for the left. This picture should help.

Mecanum wheel locations

I also included an additional chassis plate purchased from pololu robotics (https://www.pololu.com/product/1545) to house the Arduino and breadboards. This is optional but the extra space was appreciated.

I mounted the top plate using M3 standoffs. This made room for the battery pack and the PS2 controller reciever.

Mountingthehardware

The hardware that I used includes:

Arduino UNO
Adafruit Motor Shield V2
Electronics-Salon terminal shield
Lynxmotion PS2 receiver breakout board.
6 X AA battery pack with barrel jack connector
Two 400 point breadboards for LEDs and piezo
On/off switch

I started by taping down the battery pack to the middle plate. It's important to make sure this doesn't move around too much when the car is moving. I also tapped down the on/off switch next to it. The PS2 breakout board was then mounted to the underside of the top plate. The Arduino Uno (along with the two shields) was this attached to the top plate using M2.5 standoffs. I also attached the two breadboards to the top plate. The HC-SR04 modules were attached to the front and back of the car using the mounting hardware that came with them. Conveniently the EMONZY chassis plates come with screw holes that match the HC-SR04 mounting brackets. There are many ways you could arrange all of these items on the car, probably many better ways than I did it, but it worked for me.

Wiring

I have attached the wiring schematic for the whole car but it is quite busy. Below is a breakdown of where everything is wired to on the Arduino and motor shield.

DC Motors:

Motor Shield terminals M1 thru M4: positive and negative terminal. (no need to use the GND terminal)

I would recommend checking out adafruits write-up on the motor shield before started. lots of great information.

https://learn.adafruit.com/adafruit-motor-shield-v2-for-arduino/overview

Also with most DC motors, it's hard to tell the direction that you are wiring them. Would recommend tested each motor separately and swapping the wired if it is running in the wrong direction.

PS2 receiver breakout:

DAT -> Pin 12

CMD -> Pin 11

ATT -> Pin 10

CLK -> Pin 13

5V -> 5V

GND -> GND

HC-SR04: (I'm showing you the pins the code uses, but can be attached to any digital pins)

front sensor -

GND -> GND

Echo -> Pin 2

Trig -> Pin 3

VCC -> 5V

back sensor -

GND -> GND

Echo -> Pin 4

Trig -> Pin 9

VCC -> 5V

Red LED:

Anode -> Pin 7

Cathode -> GND

Yellow LED:

Anode -> Pin 6

Cathode -> GND

Green LED:

Anode -> Pin 5

Cathode -> GND

Blue LED:

Anode -> Pin 1

Cathode -> GND

*note: I wouldn't normally use pin 1 but I was out of pins. Because pin 1 and 0 are used for serial communication you can't use the serial library. If you do need to use the serial library consider getting rid of this LED.

Peizo:

Pin 8 and GND

Controlscheme:

Finishedproject:

How this project can be improved:

Cleaner wiring (maybe using a soldering prototype board)
More HC-SR04 sensors for object detection on the sides
Encoders to help account for wheel slip

Code

Omni-Car code

#include <Wire.h>
#include <Adafruit_MotorShield.h>
#include <PS2X_lib.h> //library by Bill Porter, http://www.billporter.info/2010/06/05/playstation-2-controller-arduino-library-v1-0/

// Create the motor shield object with the default I2C address
Adafruit_MotorShield AFMS = Adafruit_MotorShield();

// Creat motor objects
Adafruit_DCMotor *BackLeftMotor = AFMS.getMotor(1);
Adafruit_DCMotor *BackRightMotor = AFMS.getMotor(2);
Adafruit_DCMotor *FrontRightMotor = AFMS.getMotor(3);
Adafruit_DCMotor *FrontLeftMotor = AFMS.getMotor(4);

// create PS2 Controller Class
PS2X ps2x;

//variables used by ps2 controller
int error = 0;
byte type = 0;
byte vibrate = 0;

// variables to hold the Motor Commands
int motorSpeed = 50;                     //Speed command is stored here

//Variables used from blinking LED
int ledState = LOW;
unsigned long previousMillis = 0;
const long interval = 500;

//ultrasonic sensor variables
const int trigPinFr = 3;    //Trigger Pin for the front HC-SR04
const int echoPinFr = 2;    //Echo Pin for the front HC-SR04
const int trigPinBk = 9;    //Trigger Pin for the back HC-SR04
const int echoPinBk = 4;    //Echo Pin for the back HC-SR04

float durationFr, distanceFr;
float durationBk, distanceBk;

bool objectDetecFr = false;   //When object avoidance is on, this variable will be true if the front HC-SR04 detects an object within 15cm
bool objectDetecBk = false;   //When object avoidance is on, this variable will be true if the back HC-SR04 detects an object within 15cm
bool objectAvoidOn = false;   

bool vibrateMotors = false;   //When true the large motor in the ps2 controller will vibrate at "vibrateSpeed"
byte vibrateSpeed = 0;

void setup() {
  // put your setup code here, to run once:

  pinMode(1, OUTPUT);   //blue LED (used to indicate object avoidance mode)
  pinMode(5, OUTPUT);   //green LED
  pinMode(6, OUTPUT);   //yellow LED
  pinMode(7, OUTPUT);   //red LED

  //Front HC-SRO4 Pins
  pinMode(trigPinFr, OUTPUT);   
  pinMode(echoPinFr, INPUT);

  //Back HC-SR04 Pins
  pinMode(trigPinBk, OUTPUT);
  pinMode(echoPinBk, INPUT);

  //Initialize motor shield and PS2 controller
  AFMS.begin();
  ps2Setup();

}

void loop() {
  ps2x.read_gamepad(false,vibrateSpeed); //ps2x.read_gamepad(small motor on?, Large motor vibrate speed), set large motor vibrate speed to zero if vibration unwanted
  moveCar();  //Call this function to move the car according to joystick input
  buttons();  //Checks for button state on PS2 controller, currently just checks up and down on D-pad,circle, and X
  objectDetec();
  LEDs();
}

//Function for commanding the car to move based on the position of the joysticks. Also checks for object detection. 
void moveCar() {

  BackLeftMotor->setSpeed(motorSpeed);
  BackRightMotor->setSpeed(motorSpeed);
  FrontLeftMotor->setSpeed(motorSpeed);
  FrontRightMotor->setSpeed(motorSpeed);

  if ((ps2x.Analog(PSS_LY) < 100) && (ps2x.Analog(PSS_LX) > 100) && (ps2x.Analog(PSS_LX) < 200) && (objectDetecFr == false)) {
    //Execute forward motor commands

    BackLeftMotor->run(FORWARD);
    BackRightMotor->run(FORWARD);
    FrontLeftMotor->run(FORWARD);
    FrontRightMotor->run(FORWARD);
    vibrateSpeed = 0;

  } else if ((ps2x.Analog(PSS_LY) > 200) && (ps2x.Analog(PSS_LX) > 100) && (ps2x.Analog(PSS_LX) < 200) && (objectDetecBk == false)) {
    //Execute revese motor commands

    BackLeftMotor->run(BACKWARD);
    BackRightMotor->run(BACKWARD);
    FrontLeftMotor->run(BACKWARD);
    FrontRightMotor->run(BACKWARD);
    vibrateSpeed = 0;

  } else if ((ps2x.Analog(PSS_LX) < 100) && (ps2x.Analog(PSS_LY) > 100) && (ps2x.Analog(PSS_LY) < 200)) {
    //Execute Left motor commands

    BackLeftMotor->run(FORWARD);
    BackRightMotor->run(BACKWARD);
    FrontLeftMotor->run(BACKWARD);
    FrontRightMotor->run(FORWARD);
    vibrateSpeed = 0;

  } else if ((ps2x.Analog(PSS_LX) > 200) && (ps2x.Analog(PSS_LY) > 100) && (ps2x.Analog(PSS_LY) < 200)) {
    //Execute Right motor commands

    BackLeftMotor->run(BACKWARD);
    BackRightMotor->run(FORWARD);
    FrontLeftMotor->run(FORWARD);
    FrontRightMotor->run(BACKWARD);
    vibrateSpeed = 0;

  } else if ((ps2x.Analog(PSS_LX) > 200) && (ps2x.Analog(PSS_LY) < 100) && (objectDetecFr == false)) {
    //Execute Upper Right Diagonal motor commands

    BackLeftMotor->run(RELEASE);
    BackRightMotor->run(FORWARD);
    FrontLeftMotor->run(FORWARD);
    FrontRightMotor->run(RELEASE);
    vibrateSpeed = 0;

  }  else if ((ps2x.Analog(PSS_LX) < 100) && (ps2x.Analog(PSS_LY) < 100) && (objectDetecFr == false)) {
    //Execute Upper Left Diagonal motor commands

    BackLeftMotor->run(FORWARD);
    BackRightMotor->run(RELEASE);
    FrontLeftMotor->run(RELEASE);
    FrontRightMotor->run(FORWARD);
    vibrateSpeed = 0;

  } else if ((ps2x.Analog(PSS_LX) > 200) && (ps2x.Analog(PSS_LY) > 200) && (objectDetecBk == false)) {
    //Execute Lower Right Diagonal motor commands

    BackLeftMotor->run(BACKWARD);
    BackRightMotor->run(RELEASE);
    FrontLeftMotor->run(RELEASE);
    FrontRightMotor->run(BACKWARD);
    vibrateSpeed = 0;

  } else if ((ps2x.Analog(PSS_LX) < 100) && (ps2x.Analog(PSS_LY) > 200) && (objectDetecBk == false)) {
    //Execute Lower Left Diagonal motor commands

    BackLeftMotor->run(RELEASE);
    BackRightMotor->run(BACKWARD);
    FrontLeftMotor->run(BACKWARD);
    FrontRightMotor->run(RELEASE);
    vibrateSpeed = 0;

  } else if ((ps2x.Analog(PSS_RX) > 200)) {
    //Execute Clockwise rotate motor commands

    BackLeftMotor->run(FORWARD);
    BackRightMotor->run(BACKWARD);
    FrontLeftMotor->run(FORWARD);
    FrontRightMotor->run(BACKWARD);
    vibrateSpeed = 0;

  } else if ((ps2x.Analog(PSS_RX) < 100)) {
    //Execute anit-Clockwise rotate motor commands

    BackLeftMotor->run(BACKWARD);
    BackRightMotor->run(FORWARD);
    FrontLeftMotor->run(BACKWARD);
    FrontRightMotor->run(FORWARD);
    vibrateSpeed = 0;

  } else if ((ps2x.Analog(PSS_LY) < 100) && (ps2x.Analog(PSS_LX) > 100) && (ps2x.Analog(PSS_LX) < 200) && (objectDetecFr == true)) {
    //If car is commanded forward, object detection is on and there is an object detected in front. Vibrate controller motor and turn off car motors
    vibrateSpeed = 100;
    BackLeftMotor->run(RELEASE);
    BackRightMotor->run(RELEASE);
    FrontLeftMotor->run(RELEASE);
    FrontRightMotor->run(RELEASE);
  } else if ((ps2x.Analog(PSS_LY) > 200) && (ps2x.Analog(PSS_LX) > 100) && (ps2x.Analog(PSS_LX) < 200) && (objectDetecBk == true)) {
    //If car is commanded backwards, object detection is on and there is an object detected in back. Vibrate controller motor and turn off car motors
    vibrateSpeed = 100;
    BackLeftMotor->run(RELEASE);
    BackRightMotor->run(RELEASE);
    FrontLeftMotor->run(RELEASE);
    FrontRightMotor->run(RELEASE);    
  } else if ((ps2x.Analog(PSS_LX) > 200) && (ps2x.Analog(PSS_LY) < 100) && (objectDetecFr == true)) {
    //If car is commanded upper-right diagonal, object detection is on and there is an object detected in front. Vibrate controller motor and turn off car motors
    vibrateSpeed = 100;
    BackLeftMotor->run(RELEASE);
    BackRightMotor->run(RELEASE);
    FrontLeftMotor->run(RELEASE);
    FrontRightMotor->run(RELEASE);    
  } else if ((ps2x.Analog(PSS_LX) < 100) && (ps2x.Analog(PSS_LY) < 100) && (objectDetecFr == true)) {
    //If car is commanded upper-left diagonal, object detection is on and there is an object detected in front. Vibrate controller motor and turn off car motors
    vibrateSpeed = 100;
    BackLeftMotor->run(RELEASE);
    BackRightMotor->run(RELEASE);
    FrontLeftMotor->run(RELEASE);
    FrontRightMotor->run(RELEASE);    
  } else if ((ps2x.Analog(PSS_LX) > 200) && (ps2x.Analog(PSS_LY) > 200) && (objectDetecBk == true)) {
    //If car is commanded lower-right diagonal, object detection is on and there is an object detected in back. Vibrate controller motor and turn off car motors
    vibrateSpeed = 100;
    BackLeftMotor->run(RELEASE);
    BackRightMotor->run(RELEASE);
    FrontLeftMotor->run(RELEASE);
    FrontRightMotor->run(RELEASE);    
  } else if ((ps2x.Analog(PSS_LX) < 100) && (ps2x.Analog(PSS_LY) > 200) && (objectDetecBk == true)) {
    //If car is commanded lower-left diagonal, object detection is on and there is an object detected in back. Vibrate controller motor and turn off car motors
    vibrateSpeed = 100;
    BackLeftMotor->run(RELEASE);
    BackRightMotor->run(RELEASE);
    FrontLeftMotor->run(RELEASE);
    FrontRightMotor->run(RELEASE);    
  }
  else {
    //Stop motors and shut off vibration motor if joysticks are in default position
    BackLeftMotor->run(RELEASE);
    BackRightMotor->run(RELEASE);
    FrontLeftMotor->run(RELEASE);
    FrontRightMotor->run(RELEASE);
    vibrateSpeed = 0;

  }
}

//initialize ps2 controller, code from bill porter, http://www.billporter.info/2010/06/05/playstation-2-controller-arduino-library-v1-0/
void ps2Setup() {
  error = ps2x.config_gamepad(13, 11, 10, 12, true, true); //setup pins and settings:  GamePad(clock, command, attention, data, Pressures?, Rumble?) check for error

  if (error == 0) {
    //Serial.println("Found Controller, configured successful");
  }

  else if (error == 1) {
    //Serial.println("No controller found, check wiring, see readme.txt to enable debug. visit www.billporter.info for troubleshooting tips");
  }
  else if (error == 2) {
    //Serial.println("Controller found but not accepting commands. see readme.txt to enable debug. Visit www.billporter.info for troubleshooting tips");
  }
  else if (error == 3) {
    //Serial.println("Controller refusing to enter Pressures mode, may not support it. ");
  }
  //Serial.print(ps2x.Analog(1), HEX);

  type = ps2x.readType();
  switch (type) {
    case 0:
      //Serial.println("Unknown Controller type");
      break;
    case 1:
      //Serial.println("DualShock Controller Found");
      break;
    case 2:
      //Serial.println("GuitarHero Controller Found");
      break;
  }
}

void objectDetec() {
  //only run code of object avoidance mode is on
  if (objectAvoidOn) {
    //Read front sensor
    digitalWrite(trigPinFr, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPinFr, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPinFr, LOW);

    durationFr = pulseIn(echoPinFr, HIGH);
    distanceFr = (durationFr * .0343) / 2;

    //check if sensors read object within 15 cm
    if (distanceFr < 15) {
      objectDetecFr = true;
    } else {
      objectDetecFr = false;
    }

    //read back sensor
    digitalWrite(trigPinBk, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPinBk, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPinBk, LOW);

    durationBk = pulseIn(echoPinBk, HIGH);
    distanceBk = (durationBk * .0343) / 2;

    //check if sensor reads object within 15cm
    if (distanceBk < 15) {
      objectDetecBk = true;
    } else {
      objectDetecBk = false;
    }
  } else {
    objectDetecFr = false;
    objectDetecBk = false;
  }
}

//function used to detect button presses from user and set states based on presses
void buttons() {

  //initialize horn, horn will play until circle button (red) is released
  if (ps2x.ButtonPressed(PSB_RED)) {
    tone(8, 330); //tone(PIN,Frequency)
  }
  //horn stops when circle (red) is released
  if (ps2x.ButtonReleased(PSB_RED)) {
    noTone(8);
  }
  //toggle object avoidance when x (blue) is pressed
  if (ps2x.ButtonPressed(PSB_BLUE)) {
    objectAvoidOn = !objectAvoidOn;
  }
  //increase motor speed by 10 when up pad is pressed, up to 240
  if (ps2x.ButtonPressed(PSB_PAD_UP)) {
    if (motorSpeed < 240) {
      motorSpeed = motorSpeed + 10;
    }
  }
  //decrease motor speed by 10 when down is pressed, down to 50
  if (ps2x.ButtonPressed(PSB_PAD_DOWN)) {
    if (motorSpeed > 50) {
      motorSpeed = motorSpeed - 10;
    }
  }
}

//contolled the LEDS
void LEDs() {
  //if motor speed is less than 115, illuminate the red led, if between 119 and 181, illumiate red and yellow, if over 181 illuminate red,yellow and blue
  if (motorSpeed < 115) {
    digitalWrite(7, HIGH);
    digitalWrite(6, LOW);
    digitalWrite(5, LOW);
  } else if ((motorSpeed > 119) && (motorSpeed < 181)) {
    digitalWrite(7, HIGH);
    digitalWrite(6, HIGH);
    digitalWrite(5, LOW);
  } else if (motorSpeed > 181) {
    digitalWrite(7, HIGH);
    digitalWrite(6, HIGH);
    digitalWrite(5, HIGH);
  }

  unsigned long currentMillis = millis();

//if object avoidance is on (blue button pressed) illuminate blue LED, if object is detected, flash blue LED
  if (objectAvoidOn && !objectDetecFr && !objectDetecBk) {
    digitalWrite(1, HIGH);
  } else if (objectAvoidOn && (objectDetecFr || objectDetecBk)) {
    if (currentMillis - previousMillis >= interval) {
      // save the last time you blinked the LED
      previousMillis = currentMillis;

      // if the LED is off turn it on and vice-versa:
      if (ledState == LOW) {
        ledState = HIGH;
      } else {
        ledState = LOW;
      }

      // set the LED with the ledState of the variable:
      digitalWrite(1, ledState);
    }
  } else {
    digitalWrite(1, LOW);
  }
}

Credits

Josh Newman

0 projects • 1 follower

Arduino Omnidirectional Car

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Overview

Assembly

Wiring

Schematics

Circuit Schematic

Circuit Schematic PNG

Code

Omni-Car code

Credits

Josh Newman

Comments

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Arduino Omnidirectional Car

Arduino Omnidirectional Car

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Overview

Assembly

Wiring

Schematics

Circuit Schematic

Circuit Schematic PNG

Code

Omni-Car code

Credits

Josh Newman

Comments

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