Created November 2, 2015

Econocar RC Testing

A blend between traditional mechanical systems and modern CNC techniques

Showcase (no instructions)40

Story

ECONOCAR

I had some left over materials from previous projects and wanted to build an RC car that resembles the operation of modern cars at its simplest form. I decided that it would be the most effective to 3D print the rear axle and the steering knuckles because of the need for a precise combination of geometric shapes. Everything else, as I envisioned, could be properly manufactured through laser cut parts.

Material List

-Arduino Uno

-MDF wood

-Acrylic

-self-modded continuous TowardPro servo

-musical wire

-micro servo

Concept:

The design of the critical systems for proper RC drive

Here is the chassis base design. The lines in the middle represent support for the electrical components.

Here is the axle I designed for the drive. The square blocks serve to effectively transform the rotation of the servo into drive capability.

Schematic

STEERING SYSTEM

The steering system is powered by a servo that is connected to two 3D printed steering knuckles with custom bent musical wires. The knuckles feature an axle that allow free spin of the wheel. The use of one servo that would simultaneously turn both wheels was most economical and efficient due to my experience in building RC planes.

These are the knuckles in Cura ready to be printed

I actually had to drill the hole for the musical wire because the heated PLA ended up closing the hole created through my CAD.

I laser cut the wheels and glued them together. Then I used rubberbands to create an amazing yet cheap traction with the ground.

I then checked the whee functioning.. which was pretty darn great!

After creating the structure, I installed the wires to enable the servo to control the steering on both ends simultaneously.

Heres another side view

Here is a front view. I glued washers on the ends on the axles to prevent the wheels from falling out as they rolled and turned.

DRIVETRAIN

For the drive train, I used a modded servo as my motor since it could rotate back and forth perfectly while connected to a potentiometer and I didn't want to spend money on a DC motor. I laser cut a custom-made gear I made a couple weeks back to turn the 3D printed axle.

I first used a scroll saw to cut the servo arm as small as possible.

I then stacked two layers of gears a drilled a hole to fasten the gear to the servo.

I printed an axle that would have the gear and wheels fixed in position.

Then I put the pieces together. The gear attached to the servo arm is screwed on while the rear axle fit is rigidly positioned on a cube. Also, the servo itself is screwed on to two plates for effective powering.

FINAL ASSEMBLY

After having all the parts working the way I wanted them to, I laser cut the chassis frame and put it all together.

1 / 3

For the remote control wiring, I cut open an ethernet cable and took out the 8 individual strand wires.

1 / 2

and voila... the car in action doing a 3-point turn.

RC Wired

/* 

RC Controlled Vehicle 
by Peter Cuellar 
11/10/15
*/

#include <Servo.h>

Servo mydrive;  // create servo object to control a servo
Servo mysteering;

int potpin = 0;
int potst = 1; // analog pin used to connect the potentiometer
int val;    // variable to read the value from the analog pin
int steer;
void setup()
{
  mydrive.attach(6);
  mysteering.attach(5);
  // attaches the servo on pin 9 to the servo object
}

void loop() 
{ 
  val = analogRead(potpin);            // reads the value of the potentiometer (value between 0 and 1023) 
  val = map(val, 0, 1023, 0, 180);     // scale it to use it with the servo (value between 0 and 180) 
  mydrive.write(val);                  // sets the servo position according to the scaled value 
  delay(150);    
  
  steer = analogRead(potst);            // reads the value of the potentiometer (value between 0 and 1023) 
  steer = map(steer, 0, 1023, 55, 135);     // scale it to use it with the servo (value between 0 and 180) 
  mysteering.write(steer);                  // sets the servo position according to the scaled value 
  delay(150);  // waits for the servo to get there 
  Serial.print(steer,int);
}

Credits

Peter Cuellar

10 projects • 2 followers

Designer, Engineer, Environmentalist

Econocar RC Testing

Story

Code

RC Wired

Credits

Peter Cuellar

Comments

Embed the widget on your own site

Econocar RC Testing

Econocar RC Testing

Story

Code

RC Wired

Credits

Peter Cuellar

Comments