Created December 17, 2015

"Stella" : Remote Controlled Vehicle (Final Project)

A dual-motor control vehicle using Arduino and Bluetooth communication.

IntermediateFull instructions provided346

"Stella" : Remote Controlled Vehicle (Final Project)

Things used in this project

Hardware components

Arduino UNO

SparkFun Dual H-Bridge motor drivers L298

DC motor (generic)

4xAA battery holder

9V battery (generic)

LED light string (a necklace will do)

DC motor Wheel

Software apps and online services

Adafruit bluefruit LE App

Hand tools and fabrication machines

exacto knife

Laser cutter (generic)

Story

"Stella" Car Design

For the final iteration of my vehicle, I redesigned the body and fixed prior complications with the motor control. I crafted my vehicle chassis with organic curves, and designed it to embody serenity. The translucent paper in the car chassis diffuses the LEDs beneath and gives the car a soft, starry glow, which inspired the name "Stella".

Stella Car

Design Goals

My vehicle design had previously evolved from a tank, to a slightly better tank, to a functional car. Links to the previous iterations of the project are below:

Week 1:

https://www.hackster.io/chell-cool-13/homework-6-vehicle-prototype-3d-printed-ring-nametag-fde8b5?ref=user&ref_id=33114&offset=1

Week 2:

https://www.hackster.io/chell-cool-13/homework-7-bluetooth-controlled-vehicle-d9f52e

Week 3:

https://www.hackster.io/chell-cool-13/homework-8-finish-vehicle-5949ee

My car worked, but lacked refinement. It turns extremely quickly, and is relatively non-fluid due to the dual motor steering option I chose. It jumps almost like an animal, so I decided I wanted my design to be organic and feel “alive”. Next, I knew I wanted to incorporate light. I found the “aliveness” of the Arduino and motor controller lights to be complementary to my previous designs, and I wanted to emphasize the effect. Finally, I had had some previous problems with the motors, which I fixed.

Inspiration

I searched through countless designs for car bodies, futuristic vehicles, and lamps, as well as nature photos to find inspiration for my car. Below are the images I relied most heavily on for inspiration.

Vehicle Inspiration

1 / 11

The shape of the car and the pattern adorning it are inspired by koi fish. As I designed rough drafts of my vehicle body, I found it looked more and more aquatic. The curves mimic the movement of fish, the front of the car has a “head” like a open-mouthed koi, and the pattern falls similar to the splotch pattern of many koi fish. Koi are associated with tranquility, and so I found these animals were a good model for graceful lines, serene patterns, and organic movement.

Design

I went through roughly 17 iterations before I decided on a body design I was happy with. I also experimented with a variety of materials. I found that mat board was too stiff to work with, but that a soft, thin cardboard from the art store was perfect for modeling. My final design is made out of Bristol board, with two layers of tracing paper to serve as a window over the cut outs in the car body. Initially, I laser cut my design, but upon bringing it home, I found the laser-engrave cuts were cut too deep. In the end, I traced my laser-cut body piece and re-cut it myself using an X-acto knife.

I tried several variations of the body design itself. I played with the idea of having two arms extending toward the front of the car like a crouching animal, but I found the proportions difficult to work with. Folding the arms in (into the open-mouthed koi shape) gave the body more dimension and better proportions. The base was cut out of a soft wood composite board, with slots cut to attach zip ties and screw down the Arduino. I made a few changes to the arrangement of the wheels as well. I attached the motors to the underside of the vehicle instead of the top of the base, which gave my vehicle more height and clearance for going up ramps. I also reduced the size of the front wheels, which had previously been very large. The front wheels are attached underneath, and housed within the body of the vehicle.

The shell itself is mounted using thread. I used a needle to attach thread to the back of the car, and threaded it through holes in the base to make a simple hinge. The front attaches loosely with a small piece of wire, and is easy to detach and lift up. For added lights, I found by far the easiest solution was to buy a cheap LED string necklace and drape it across the interior. This simple solution saved me a great deal of time.

Drawings

1 / 15 • caption (optional)

Design Process

1 / 16 • I went through a total of 17 designs before I was satisfied

Illustrator Files

1 / 2 • laser cut illustrator files

Electronics and Code

My electronics worked well from my previous design iterations, so I opted not to change them too much. However, I had some trouble that I thought originated in my code. One wheel of my vehicle wouldn’t turn backward, and my car would not run backward. After establishing that it wasn't a code problem, I thought it was a problem with the motor. After switching parts out, the problem persisted. Finally, (after asking an expert) I realized that my vehicle wasn’t running properly because I had a control pin for one of the motors attached to pin 1 on the Arduino. This pin (along with pin 0) is what the Arduino uses to communicate with the computer. Attaching the motor to this pin caused problems with the signal. I fixed it by attaching this pin to pin 6 instead.

I used a small wood board to screw the Arduino onto, and I offset it with a few wood pieces so that it hovered over the circuit board and wheels. Also, I covered the wheels with cut balloons in order to increase traction.

Finished Piece and Video

Finished Stella Car

1 / 4 • Finished Stella Car

Youtube Video

https://youtu.be/XnSpt9tU8gs

Future Design Innovations

I am very pleased with the car as it turned out, but there is always room for refinement. I found I had some problems with the front wheels-- they were too loose and could use more constraints. The car might also do well with a sturdier material. The paper shell was easy to work with and looked fine, but it is not durable in the long run. My electronics, also, could have used some refinement and constraints on the wires. If I were to build this car again, I would pay more attention to anchoring electronic pieces to the base with either walls along the base of the car, or with screws. Overall, though, it works quite well!

Code

Dual Motor Control using Bluefruit LE Bluetooth Device

/*********************************************************************
 This is an example for our nRF51822 based Bluefruit LE modules

 Pick one up today in the adafruit shop!

 Adafruit invests time and resources providing this open source code,
 please support Adafruit and open-source hardware by purchasing
 products from Adafruit!

 MIT license, check LICENSE for more information
 All text above, and the splash screen below must be included in
 any redistribution
*********************************************************************/

#include <string.h>
#include <Arduino.h>
#include <SPI.h>
#if not defined (_VARIANT_ARDUINO_DUE_X_) && not defined (_VARIANT_ARDUINO_ZERO_)
  #include <SoftwareSerial.h>
#endif

#include "Adafruit_BLE.h"
#include "Adafruit_BluefruitLE_SPI.h"
#include "Adafruit_BluefruitLE_UART.h"

#include "BluefruitConfig.h"

/*=========================================================================
    APPLICATION SETTINGS

    FACTORYRESET_ENABLE       Perform a factory reset when running this sketch
   
                              Enabling this will put your Bluefruit LE module
                              in a 'known good' state and clear any config
                              data set in previous sketches or projects, so
                              running this at least once is a good idea.
   
                              When deploying your project, however, you will
                              want to disable factory reset by setting this
                              value to 0.  If you are making changes to your
                              Bluefruit LE device via AT commands, and those
                              changes aren't persisting across resets, this
                              is the reason why.  Factory reset will erase
                              the non-volatile memory where config data is
                              stored, setting it back to factory default
                              values.
       
                              Some sketches that require you to bond to a
                              central device (HID mouse, keyboard, etc.)
                              won't work at all with this feature enabled
                              since the factory reset will clear all of the
                              bonding data stored on the chip, meaning the
                              central device won't be able to reconnect.
    MINIMUM_FIRMWARE_VERSION  Minimum firmware version to have some new features
    MODE_LED_BEHAVIOUR        LED activity, valid options are
                              "DISABLE" or "MODE" or "BLEUART" or
                              "HWUART"  or "SPI"  or "MANUAL"
    -----------------------------------------------------------------------*/
    #define FACTORYRESET_ENABLE         1
    #define MINIMUM_FIRMWARE_VERSION    "0.6.6"
    #define MODE_LED_BEHAVIOUR          "MODE"
/*=========================================================================*/

// Create the bluefruit object, either software serial...uncomment these lines
SoftwareSerial bluefruitSS = SoftwareSerial(BLUEFRUIT_SWUART_TXD_PIN, BLUEFRUIT_SWUART_RXD_PIN);

Adafruit_BluefruitLE_UART ble(bluefruitSS, BLUEFRUIT_UART_MODE_PIN,
                      BLUEFRUIT_UART_CTS_PIN, BLUEFRUIT_UART_RTS_PIN);

/* ...or hardware serial, which does not need the RTS/CTS pins. Uncomment this line */
//Adafruit_BluefruitLE_UART ble(BLUEFRUIT_HWSERIAL_NAME, BLUEFRUIT_UART_MODE_PIN);

/* ...hardware SPI, using SCK/MOSI/MISO hardware SPI pins and then user selected CS/IRQ/RST */
//Adafruit_BluefruitLE_SPI ble(BLUEFRUIT_SPI_CS, BLUEFRUIT_SPI_IRQ, BLUEFRUIT_SPI_RST);

/* ...software SPI, using SCK/MOSI/MISO user-defined SPI pins and then user selected CS/IRQ/RST */
//Adafruit_BluefruitLE_SPI ble(BLUEFRUIT_SPI_SCK, BLUEFRUIT_SPI_MISO,
//                             BLUEFRUIT_SPI_MOSI, BLUEFRUIT_SPI_CS,
//                             BLUEFRUIT_SPI_IRQ, BLUEFRUIT_SPI_RST);


int enA = 5;
int in1 = 6;
int in2 = 2;
// motor two
int enB = 3;
int in3 = 7;
int in4 = 4;


// A small helper
void error(const __FlashStringHelper*err) {
  Serial.println(err);
  while (1);
}

// function prototypes over in packetparser.cpp
uint8_t readPacket(Adafruit_BLE *ble, uint16_t timeout);
float parsefloat(uint8_t *buffer);
void printHex(const uint8_t * data, const uint32_t numBytes);

// the packet buffer
extern uint8_t packetbuffer[];


/**************************************************************************/
/*!
    @brief  Sets up the HW an the BLE module (this function is called
            automatically on startup)
*/
/**************************************************************************/
void setup(void)
{
  // set all the motor control pins to outputs
  pinMode(enA, OUTPUT);
  pinMode(enB, OUTPUT);
  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(in3, OUTPUT);
  pinMode(in4, OUTPUT);
  
  while (!Serial);  // required for Flora & Micro
  delay(500);

  Serial.begin(115200);
  Serial.println(F("Adafruit Bluefruit App Controller Example"));
  Serial.println(F("-----------------------------------------"));

  /* Initialise the module */
  Serial.print(F("Initialising the Bluefruit LE module: "));

  if ( !ble.begin(VERBOSE_MODE) )
  {
    error(F("Couldn't find Bluefruit, make sure it's in CoMmanD mode & check wiring?"));
  }
  Serial.println( F("OK!") );

  if ( FACTORYRESET_ENABLE )
  {
    /* Perform a factory reset to make sure everything is in a known state */
    Serial.println(F("Performing a factory reset: "));
    if ( ! ble.factoryReset() ){
      error(F("Couldn't factory reset"));
    }
  }


  /* Disable command echo from Bluefruit */
  ble.echo(false);

  Serial.println("Requesting Bluefruit info:");
  /* Print Bluefruit information */
  ble.info();

  Serial.println(F("Please use Adafruit Bluefruit LE app to connect in Controller mode"));
  Serial.println(F("Then activate/use the sensors, color picker, game controller, etc!"));
  Serial.println();

  ble.verbose(false);  // debug info is a little annoying after this point!

  /* Wait for connection */
  while (! ble.isConnected()) {
      delay(500);
  }

  Serial.println(F("******************************"));

  // LED Activity command is only supported from 0.6.6
  if ( ble.isVersionAtLeast(MINIMUM_FIRMWARE_VERSION) )
  {
    // Change Mode LED Activity
    Serial.println(F("Change LED activity to " MODE_LED_BEHAVIOUR));
    ble.sendCommandCheckOK("AT+HWModeLED=" MODE_LED_BEHAVIOUR);
  }

  // Set Bluefruit to DATA mode
  Serial.println( F("Switching to DATA mode!") );
  ble.setMode(BLUEFRUIT_MODE_DATA);

  Serial.println(F("******************************"));

}

/**************************************************************************/
/*!
    @brief  Constantly poll for new command or response data
*/
/**************************************************************************/
void loop(void)
{
  /* Wait for new data to arrive */
  uint8_t len = readPacket(&ble, BLE_READPACKET_TIMEOUT);
  if (len == 0) return;

  /* Got a packet! */
  // printHex(packetbuffer, len);

  // Color
  if (packetbuffer[1] == 'C') {
    uint8_t red = packetbuffer[2];
    uint8_t green = packetbuffer[3];
    uint8_t blue = packetbuffer[4];
    Serial.print ("RGB #");
    if (red < 0x10) Serial.print("0");
    Serial.print(red, HEX);
    if (green < 0x10) Serial.print("0");
    Serial.print(green, HEX);
    if (blue < 0x10) Serial.print("0");
    Serial.println(blue, HEX);
  }

  // Buttons
  if (packetbuffer[1] == 'B') {
    uint8_t buttnum = packetbuffer[2] - '0';
    boolean pressed = packetbuffer[3] - '0';
    Serial.print ("Button "); Serial.print(buttnum);
    if (pressed) {
      Serial.println(" pressed");
      if (buttnum == 5) {
        digitalWrite(in1, HIGH);
        digitalWrite(in2, LOW);
        digitalWrite(in3, HIGH);
        digitalWrite(in4, LOW);
        analogWrite(enA, 255);
        analogWrite(enB, 255);
        //delay(500);
      }
      else if (buttnum == 6) {
       digitalWrite(in1, LOW);
       digitalWrite(in2, HIGH);
       digitalWrite(in3, LOW);
       digitalWrite(in4, HIGH);
       analogWrite(enA, 255);
       analogWrite(enB, 255);
       //delay(500)
      }
      else if (buttnum == 8) {
       digitalWrite(in1, LOW);
       digitalWrite(in2, HIGH);  
       digitalWrite(in3, HIGH);
       digitalWrite(in4, LOW); 
       analogWrite(enA, 255);
       analogWrite(enB, 255);
       //delay(500)
      }
      else if (buttnum == 7) {
       digitalWrite(in1, HIGH);
       digitalWrite(in2, LOW);  
       digitalWrite(in3, LOW);
       digitalWrite(in4, HIGH);
       analogWrite(enA, 255);
       analogWrite(enB, 255);
       //delay(500);
      }
    } else {
      Serial.println(" released");
      digitalWrite(in1, LOW);
      digitalWrite(in2, LOW);
      digitalWrite(in3, LOW);
      digitalWrite(in4, LOW);
      analogWrite(enA, 0);
      analogWrite(enB, 0);
    }
  }

  // GPS Location
  if (packetbuffer[1] == 'L') {
    float lat, lon, alt;
    lat = parsefloat(packetbuffer+2);
    lon = parsefloat(packetbuffer+6);
    alt = parsefloat(packetbuffer+10);
    Serial.print("GPS Location\t");
    Serial.print("Lat: "); Serial.print(lat, 4); // 4 digits of precision!
    Serial.print('\t');
    Serial.print("Lon: "); Serial.print(lon, 4); // 4 digits of precision!
    Serial.print('\t');
    Serial.print(alt, 4); Serial.println(" meters");
  }

  // Accelerometer
  if (packetbuffer[1] == 'A') {
    float x, y, z;
    x = parsefloat(packetbuffer+2);
    y = parsefloat(packetbuffer+6);
    z = parsefloat(packetbuffer+10);
    Serial.print("Accel\t");
    Serial.print(x); Serial.print('\t');
    Serial.print(y); Serial.print('\t');
    Serial.print(z); Serial.println();
  }

  // Magnetometer
  if (packetbuffer[1] == 'M') {
    float x, y, z;
    x = parsefloat(packetbuffer+2);
    y = parsefloat(packetbuffer+6);
    z = parsefloat(packetbuffer+10);
    Serial.print("Mag\t");
    Serial.print(x); Serial.print('\t');
    Serial.print(y); Serial.print('\t');
    Serial.print(z); Serial.println();
  }

  // Gyroscope
  if (packetbuffer[1] == 'G') {
    float x, y, z;
    x = parsefloat(packetbuffer+2);
    y = parsefloat(packetbuffer+6);
    z = parsefloat(packetbuffer+10);
    Serial.print("Gyro\t");
    Serial.print(x); Serial.print('\t');
    Serial.print(y); Serial.print('\t');
    Serial.print(z); Serial.println();
  }

  // Quaternions
  if (packetbuffer[1] == 'Q') {
    float x, y, z, w;
    x = parsefloat(packetbuffer+2);
    y = parsefloat(packetbuffer+6);
    z = parsefloat(packetbuffer+10);
    w = parsefloat(packetbuffer+14);
    Serial.print("Quat\t");
    Serial.print(x); Serial.print('\t');
    Serial.print(y); Serial.print('\t');
    Serial.print(z); Serial.print('\t');
    Serial.print(w); Serial.println();
  }
}

Credits

Maggie George

9 projects • 5 followers

"Stella" : Remote Controlled Vehicle (Final Project)

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

"Stella" Car Design

Schematics

Schematic

Laser Cut Ai File Base

Laser Cut Ai File Shell

Code

Dual Motor Control using Bluefruit LE Bluetooth Device

Credits

Maggie George

Comments

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"Stella" : Remote Controlled Vehicle (Final Project)

"Stella" : Remote Controlled Vehicle (Final Project)

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

"Stella" Car Design

Schematics

Schematic

Laser Cut Ai File Base

Laser Cut Ai File Shell

Code

Dual Motor Control using Bluefruit LE Bluetooth Device

Credits

Maggie George

Comments

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