Created November 10, 2015

Project Two: Final Remote Control Car

Full instructions provided313

Things used in this project

Hardware components

Arduino UNO

L298 H-bridge

9V battery and battery pack

4 AA batteries and 6V battery pack

1 Perfboard

1 protoshield

4 switches

4 1-in screws and corresponding nuts and washers

DC motor (generic)

And 2 wheels that fit, along with 1 marble

rubber wheels

stranded wire

solid core wire

heat shrink wrap

CA glue

Hand tools and fabrication machines

Laser cutter (generic)

3D Printer (generic)

Soldering iron (generic)

Story

Making a remote control car

The task for this project was to make a remote control car that can:

-Travel forwards, backwards, left, and right

-Drive in a straight line for 5 ft, within a 1 ft wide space

-Park in a 16x16in square

-Go up a 3ft long x 1ft tall ramp

My first iterations can be found here:

https://www.hackster.io/adammansour/homework-6-137703?ref=user&ref_id=31424&offset=0

The first iteration of the project was structurally unsound, and overly compact for all of the components I needed to set on it (2 battery packs, an Arduino, and an H-bridge), so in this iteration, I decided to pursue a simple, large, base structure. In addition, I strayed from using a servo to control steering, and focused on using differential steering (having the two wheels turn at different speeds) to control the vehicle.

These design decisions helped simplify the device, and let me focus on making it easily maneuverable, modifiable, and structurally sound. I used acrylic to build the majority of this vehicle and its remote because of its clean look and structural rigidity.

The Base

In designing a new structure for the base, I began by thinking about how I could fit all of the aforementioned components of the device onto the car. I measured each component, and drafted each part's shapes on Illustrator, to be engraved on the bottom of the device. Next, I designed a rounded shape for the base to reduce risk of damage upon impact, as any force imparted would be spread more effectively.

Here is how it turned out (the file I printed is attached to this page):

The vehicle base

Note that the holes around the Arduino and H-Bridge were for zip-tying the components down, and that the 6 rectangles under the H-Bridge are for looping the remote control leash through, so that any pulling of the leash imparted force on the base and not the electronics to which the leash wires will be attached. The holes at the very bottom of the base are to attach the 3D printed marble caster, which serves as the stabilizer of the vehicle, alongside the two wheels attached to the motors at the top. I used double-sided tape to attach the gear motors and wheels to the base, as shown below. I also tested to see whether the motors needed to be oriented in the same direction for the car to go straight, but in all orientations, the right motor tended to be faster than the left.

The gear motor and wheel attached by double-sided tape

1 / 2 • The marble holder screwed into the board

Circuitry

Next, I hooked up the circuitry of the vehicle. This consisted of an Arduino, H-Bridge, solderless breadboard, a 9V battery pack attached to the Arduino, and a 6V pack powering the motors. The motors are attached to the H-bridge as output, and the H-bridge is connected to pins on the Arduino, each controlling a different directional function of the vehicle (forward, backward, left, and right). These controls were hosted by switches on the solderless breadboard, each grounded to the Arduino, and powered by digital pins also on the Arduino. There are no resistors involved as I used the internal resistor of the Arduino, as controlled in my code (attached to this page).

Next, I began transitioning the circuitry from jumper cables plugged directly into the solderless breadboard and Arduino, to a soldered proto shield.

Before: jumper cables plugged into the Arduino directly

1 / 3 • Connecting the header pins to the terminals from below

The Remote

For a more permanent and ergonomic solution to controlling the vehicle from a distance, I transferred the solderless breadboard of switches to a perfboard with larger switches, but the same general circuitry. Each switch is still connected to a pin on the Arduino for a different direction, as well as the ground. The wires connecting the switches to the proto shied are long, stranded wires all attached by insulation.

All of these connections are pictured below.

The layout of the remote is intended to be ergonomic, and intuitive in that forward and backward are together, controlled by the left hand, and right and left are controlled by the right hand. The buttons are spaced for comfortable holding.

1 / 3

Here is a rough paper prototype that helped me determine how to space the switches on the perfboard.

A crude prototype, I later swapped the left/right and forward/backward buttons

Here's how it turned out:

This solution, however, was far from sleek. I decided to make a casing of sorts to house the perfboard. I wanted to make a remote that would allow the car to be picked up by the remote without straining the wires, as well as one that could be comfortable to hold for a long period of time, with intuitive and clear indications of how to control the vehicle. To do so, I engraved a hole for the leash wires to loop through and engraved which direction each button corresponded to onto the remote, respectively.

The series of photos below shows my process from making paper prototypes, which I evolved to best fit the remote through rapid iterations, and ultimately fastening the laser cut remote to the perfboard with screws, washers, nuts, and laser-cut spacers.

An initial paper prototype

Subsequent lasercut iterations, adapted for ergonomics and button fit

The first acrilic iteration, without fastener holes

The remote with fasteners, prior to assembly

Spacers inside the remote to reduce pressure on the perfboard

The assembled remote (top)

The assembled remote (bottom)

Next, I added buttons atop the switches that were more easily pressable than those flush with the remote (glued with CA)

The looped leash wires

Final Wire Attachments

Next, I looped the leash wires through the base of the vehicle, and connected them to the terminals soldered to the protoshield. These connections proved to be inconsistent, leading the car to intermittently work and stop, so I soldered the stranded wires of the leash, to solid core wires and heat shrunk them together, as shown in the pictures below.

The Final Product

Ultimately, the remote control car was successful in the criteria of the task, but it had trouble going up the ramp in the forward direction. In the future, I would add more traction to the wheels, or use 2 more motorized wheels to make the car more powerful in scaling inclines.

Here are a video and photo of how it turned out!

Schematics

Code

Code for steering control

const int switchPinLeft = 12;    // switch input
const int switchPinRight = 9;    // Enable for Motor 1
const int switchPinForward = 10;    // Enable for Motor 2
const int switchPinBackward = 11;
const int switchPinStation = 13;
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 = 3;    // H-bridge leg 3 (pin 10, 3A)
const int motor4Pin = 2;    // H-bridge leg 4 (pin 15, 4A)
int buttonStateLeft = LOW;
int buttonStateRight = LOW;
int buttonStateForward = LOW;
int buttonStateBackward = LOW;
int buttonStateStation = LOW;

void setup() {
  // set the switch as an input:
  pinMode(switchPinLeft, INPUT_PULLUP);
  pinMode(switchPinRight, INPUT_PULLUP);
  pinMode(switchPinForward, INPUT_PULLUP);
  pinMode(switchPinBackward, INPUT_PULLUP);
  pinMode(switchPinStation, INPUT_PULLUP);


  // set all the other pins you're using as outputs:
  pinMode(switchPinLeft, OUTPUT);
  pinMode(switchPinRight, OUTPUT);
  pinMode(motor1Pin, OUTPUT);
  pinMode(motor2Pin, OUTPUT);
  pinMode(motor3Pin, OUTPUT);
  pinMode(motor4Pin, OUTPUT);


}
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
}


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
}

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
}


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
}

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
}
void loop() {


  buttonStateLeft = digitalRead(switchPinLeft);
  buttonStateRight = digitalRead(switchPinRight);
  buttonStateForward = digitalRead(switchPinForward);
  buttonStateBackward = digitalRead(switchPinBackward);
  buttonStateStation = digitalRead(switchPinStation);
  
  if (buttonStateForward == HIGH && buttonStateBackward == LOW) { //forward switch are pressed
    forward();
  }
  else if (buttonStateRight == HIGH && buttonStateLeft == LOW) { //right switch is pressed
    right();
  }

  else if (buttonStateRight == LOW && buttonStateLeft == HIGH) { //left switch is pressed
    left();
  }

   else if (buttonStateForward == LOW && buttonStateBackward == HIGH) { //backward switch is pressed
    backward();
    
  }
 else if (buttonStateStation == HIGH) { //none are pressed
    station();
    
  }


}

Credits

Adam Mansour

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Project Two: Final Remote Control Car

Things used in this project

Hardware components

Hand tools and fabrication machines

Story

Making a remote control car

The Base

Circuitry

The Remote

Final Wire Attachments

The Final Product

Custom parts and enclosures

The vehicle base

The top of the remote casing

The bottom of the remote casing

Spacers for the inside of the remote casing

Schematics

Schematic

Code

Code for steering control

Credits

Adam Mansour

Comments

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Project Two: Final Remote Control Car

Project Two: Final Remote Control Car

Things used in this project

Hardware components

Hand tools and fabrication machines

Story

Making a remote control car

The Base

Circuitry

The Remote

Final Wire Attachments

The Final Product

Custom parts and enclosures

The vehicle base

The top of the remote casing

The bottom of the remote casing

Spacers for the inside of the remote casing

Schematics

Schematic

Code

Code for steering control

Credits

Adam Mansour

Comments