Created December 18, 2015

Final Remote Controlled Car with Revised Chassis

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Story

The Task

For the last stage of the remote control building process, we were tasked with evolving the chassis from our last iteration.

With little time, and lots of help from Chris, I pursued this design, shown in the sketch below and my final Illustrator file.

I wanted to create a slanted chassis with the weight of the vehicle dominantly in the front, for more traction when ascending ramps. This would put more weight on the weights, versus the marble at the back of the vehicle. The cut outs on the back of the vehicle cut the weight, but also served their purpose aesthetically.

I tested my first iteration with cardboard, and tried out many different hole placements for where my Arduino and H-bridge would be fastened to the vehicle. The two holes on the left of the picture are for fastening the 3D printed marble holder I attached to the back.

I tried folding the car at a 20 degree angle, for a subtle slant, and found that i would need to bend the final vehicle at the marble-roller base end as well.

My next iteration, with suggestions from Chris to be more Tron-like, was largely similar in structure, but I changed the fastening holes to slots, in horizontal and vertical directions to allow for the most flexibility in fastening, in addition to looking cleaner than a bunch of holes. The tail end of the vehicle was also slimmer, so I rotated the fastening holes for the marble holder to fit.

Here's how the Arduino, H-bridge, and motors all fit onto the cardboard prototype. As a result, I widened the chassis, and rotated the orientation of the Arduino and H-bridge, for a cleaner cable layout in the next iteration.

In the next iteration, I used acrylic, and used an acrylic bender, which heats the plastic, to reshape the design, shown below.

Here's how it turned out

I tried the prototype again (in green below), this time with a steeper incline, to test its balance, aesthetics, and traction on the ramp. On all fronts, the more subtle incline was more successful.

Next, I used risers, screws, and nylon nuts to fasten the H-bridge (right) and Arduino (left), to the vehicle. Prior to this, I transferred the connections of the Bluetooth receiver and Arduino to an Arduino proto shield, which worked great. Later, I replace the jumper wires with shorter leads.

Here's how it turned out with the gear motors attached by double sided mounting tape, and the marble holder fastened to the back. I also added holes for the gear motors' wires to reach the Arduino more directly and ziptied wires for a cleaner look.

Here's how it drove:

https://youtu.be/CbkL2NOb30c

Code

Control Code

#include <SPI.h>
#include "Adafruit_BLE_UART.h"

// Connect CLK/MISO/MOSI to hardware SPI
// e.g. On UNO & compatible: CLK = 13, MISO = 12, MOSI = 11
#define ADAFRUITBLE_REQ 10
#define ADAFRUITBLE_RDY 2     // This should be an interrupt pin, on Uno thats #2 or #3
#define ADAFRUITBLE_RST 9

Adafruit_BLE_UART BTLEserial = Adafruit_BLE_UART(ADAFRUITBLE_REQ, ADAFRUITBLE_RDY, ADAFRUITBLE_RST);


bool leftButtonDown = false;
bool rightButtonDown = false;
bool forwardButtonDown = false;
bool backwardButtonDown = false;



const int motor1Pin = 7;    // H-bridge leg 1 (pin 2, 1A)
const int motor2Pin = 6;    // H-bridge leg 2 (pin 7, 2A)
const int motor3Pin = 5;    // H-bridge leg 3 (pin 10, 3A)
const int motor4Pin = 4;    // H-bridge leg 4 (pin 15, 4A)


/**************************************************************************/
/*!
    Configure the Arduino and start advertising with the radio
*/
/**************************************************************************/

void backward() {


  digitalWrite(motor1Pin, HIGH);   // set leg 1A of the H-bridge HIGH
  digitalWrite(motor2Pin, LOW);  // set leg 2A of the H-bridge low
  digitalWrite(motor3Pin, HIGH);   // set leg 1B of the H-bridge high
  digitalWrite(motor4Pin, LOW);  // set leg 2B of the H-bridge low
  Serial.println("backward");
}


void forward() {
  digitalWrite(motor1Pin, LOW);  // set leg 1A of the H-bridge LOW
  digitalWrite(motor2Pin, HIGH);   // set leg 2A of the H-bridge high
  digitalWrite(motor3Pin, LOW);   // set leg 1B of the H-bridge low
  digitalWrite(motor4Pin, HIGH);  // set leg 2B of the H-bridge high
  Serial.println("forward");
}

void left() {

  digitalWrite(motor1Pin, LOW);  // set leg 1A of the H-bridge low
  digitalWrite(motor2Pin, LOW);   // set leg 2A of the H-bridge low
  digitalWrite(motor3Pin, HIGH);   // set leg 1B of the H-bridge high
  digitalWrite(motor4Pin, LOW);  // set leg 2B of the H-bridge low
  Serial.println("left");
}


void right() {
  digitalWrite(motor1Pin, HIGH);  // set leg 1A of the H-bridge high
  digitalWrite(motor2Pin, LOW);   // set leg 2A of the H-bridge low
  digitalWrite(motor3Pin, LOW);  // set leg 1A of the H-bridge low
  digitalWrite(motor4Pin, LOW);   // set leg 2A of the H-bridge low
  Serial.println("right");
}

void station()  {
  
  digitalWrite(motor1Pin, LOW);  // set leg 1A of the H-bridge low
  digitalWrite(motor2Pin, LOW);   // set leg 2A of the H-bridge low
  digitalWrite(motor3Pin, LOW);  // set leg 1A of the H-bridge low
  digitalWrite(motor4Pin, LOW);   // set leg 2A of the H-bridge low
  Serial.println("station");
}

void setup(void)
{ 
  Serial.begin(9600);
  while(!Serial); // Leonardo/Micro should wait for serial init
  Serial.println(F("Adafruit Bluefruit Low Energy nRF8001 Print echo demo"));

  // BTLEserial.setDeviceName("NEWNAME"); /* 7 characters max! */

  BTLEserial.begin();

//  pinMode(2, INPUT_PULLUP);
//  pinMode(9, INPUT_PULLUP);
//  pinMode(10, INPUT_PULLUP);
//  pinMode(11, INPUT_PULLUP);
//  pinMode(12, INPUT_PULLUP);
//  pinMode(13, INPUT_PULLUP);
//  // set all the other pins you're using as outputs:
//  
//  pinMode(motor1Pin, OUTPUT);
//  pinMode(motor2Pin, OUTPUT);
//  pinMode(motor3Pin, OUTPUT);
//  pinMode(motor4Pin, OUTPUT);
}

/**************************************************************************/
/*!
    Constantly checks for new events on the nRF8001
*/
/**************************************************************************/
aci_evt_opcode_t laststatus = ACI_EVT_DISCONNECTED;

char leftButtonDownSignal[] = { '!', 'B', '7', '1', '4' };
char leftButtonUpSignal[] = { '!', 'B', '7', '0', '5' };

char rightButtonDownSignal[] = { '!', 'B', '8', '1', '3' };
char rightButtonUpSignal[] = { '!', 'B', '8', '0', '4' };

char forwardButtonDownSignal[] = { '!', 'B', '5', '1', '6' };
char forwardButtonUpSignal[] = { '!', 'B', '5', '0', '7' };

char backwardButtonDownSignal[] = { '!', 'B', '6', '1', '5' };
char backwardButtonUpSignal[] = { '!', 'B', '6', '0', '6' };



void readSignal(char signalBytes[]) {
  for (int i = 0; i < 5; i++) {
    signalBytes[i] = BTLEserial.read();
  }
}

bool signalsEqual(char signal1[], char signal2[]) {
  for (int i = 0; i < 5; i++) {
    if (signal1[i] != signal2[i]) {
      return false;
    }
  }
  return true;
}


void loop()
{
  // Tell the nRF8001 to do whatever it should be working on.
  BTLEserial.pollACI();

  // Ask what is our current status
  aci_evt_opcode_t status = BTLEserial.getState();
  // If the status changed....
  if (status != laststatus) {
    // print it out!
    if (status == ACI_EVT_DEVICE_STARTED) {
        Serial.println(F("* Advertising started"));
    }
    if (status == ACI_EVT_CONNECTED) {
        Serial.println(F("* Connected!"));
    }
    if (status == ACI_EVT_DISCONNECTED) {
        Serial.println(F("* Disconnected or advertising timed out"));
    }
    // OK set the last status change to this one
    laststatus = status;
  }

  if (status == ACI_EVT_CONNECTED) {
    // Lets see if there's any data for us!
    if (BTLEserial.available()) {
      Serial.print("* "); Serial.print(BTLEserial.available()); Serial.println(F(" bytes available from BTLE"));
    }
    // OK while we still have something to read, get a character and print it out
    char signalBytes[5];
    if (BTLEserial.available() >= 5) {
        readSignal(signalBytes);
        
        for (int i = 0; i < 5; i++) {
          Serial.print(signalBytes [i]);
        }
        if (signalsEqual(signalBytes, leftButtonDownSignal)) {
          leftButtonDown = true;
        }
        if (signalsEqual(signalBytes, rightButtonDownSignal)) {
          rightButtonDown = true;
        }
        if (signalsEqual(signalBytes, forwardButtonDownSignal)) {
          forwardButtonDown = true;
        }
        if (signalsEqual(signalBytes, backwardButtonDownSignal)) {
          backwardButtonDown = true;
        }
        if (signalsEqual(signalBytes, leftButtonUpSignal)) {
          leftButtonDown = false;
        }
        if (signalsEqual(signalBytes, rightButtonUpSignal)) {
          rightButtonDown = false;
        }
        if (signalsEqual(signalBytes, forwardButtonUpSignal)) {
          forwardButtonDown = false;
        }
        if (signalsEqual(signalBytes, backwardButtonUpSignal)) {
          backwardButtonDown = false;
        }
    }

    // Next up, see if we have any data to get from the Serial console

    if (Serial.available()) {
      // Read a line from Serial
      Serial.setTimeout(100); // 100 millisecond timeout
      String s = Serial.readString();

      // We need to convert the line to bytes, no more than 20 at this time
      uint8_t sendbuffer[20];
      s.getBytes(sendbuffer, 20);
      char sendbuffersize = min(20, s.length());

      Serial.print(F("\n* Sending -> \"")); Serial.print((char *)sendbuffer); Serial.println("\"");

      // write the data
      BTLEserial.write(sendbuffer, sendbuffersize);
    }

  if (forwardButtonDown && !backwardButtonDown) { //forward button are pressed
    forward();
  }
  else if (rightButtonDown && !leftButtonDown) { //right button is pressed
    right();
  }

  else if (leftButtonDown && !rightButtonDown) { //left button is pressed
    left();
  }

   else if (backwardButtonDown && !forwardButtonDown) { //backward switch is pressed
    backward();
    
  }
 else if (!backwardButtonDown && !forwardButtonDown && !leftButtonDown && !rightButtonDown) { //none are pressed
    station();
    
  }
    
  }


}

Credits

Adam Mansour

10 projects • 1 follower

Final Remote Controlled Car with Revised Chassis

Story

Schematics

Schematic

Code

Control Code

Credits

Adam Mansour

Comments

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Final Remote Controlled Car with Revised Chassis

Final Remote Controlled Car with Revised Chassis

Story

Schematics

Schematic

Code

Control Code

Credits

Adam Mansour

Comments