Created November 10, 2015

Second Project Final Week

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Things used in this project

Hardware components

Arduino UNO

9V battery (generic)

aa battery

metal axel

gears

screws

wheels

lock pin and column

econowood

Rotary potentiometer (generic)

push button switch

Arduino Proto Shield

solid core

stranded wire

Story

This part was to finish the final project. There were a few things I wanted to fix from last week. First, because the gears were wooden, it was easy for the gear teeth to break. I ended up using acryllic to print the gears. This proved to be a lot more sturdy. In order to ensure that the top gear would stay fixed on the metal axel, I used a lock pin and collar fastener, glued to the gear and set in place using a set screw. This is shown below

Above, I am showing the new axel that I am using. It is thicker in diameter, which proved to be a lot sturdier than my previous axel. I also used this axel because it perfectly fits the 3d printed wheels that Chris gave me. Below is a picture of the 3d printer wheels. I'm using a set screw to keep the wheels on the axel.

I had to print a few wheels with different sizes in order to match with the 3d printed wheel. I also made sure that the wheel in between the 3d printed wheel and the laser cut wheel would be a bit smaller in diameter in order to provide a channel for the rubber bands that I would later place to provide traction.

After upgrading my mechanical components, I used a protoshield, with wires soldered on to them. This process took a while, maybe 5 hours to ensure that I wouldn't generate a short circuit. After soldering the wires, I made a mistake by powering the servos to the 5V rail. However I found out that the 5v cannot power the servos so I had to resolder the servo power wires to a wire that would run to the external battery pack. Above is a picture of the final solder job.

Finally, I created a game console by placing a larger potentiometer, and two larger switches onto a protoboard.

In conclusion, my vehicle could not steer very well because there is so much more traction on the back wheels and not much on the front wheels. In the future I will hope to make the back wheels smaller and front wheel larger, and also keep more weight in the front so that the steering would be better.

Knob-trial.ino

/* 
 Controlling a servo position using a potentiometer (variable resistor) 
 by Michal Rinott <http://people.interaction-ivrea.it/m.rinott> 

 modified on 8 Nov 2013
 by Scott Fitzgerald
 http://www.arduino.cc/en/Tutorial/Knob
*/

#include <Servo.h>

Servo steer;  // create servo object to control a servo
Servo power;
//Servo myservo2;
const int backBtn = 2; 
const int forwardBtn = 3;
int forwardBtnState = 0;
int backBtnState = 0;

int potpin = 0;  // analog pin used to connect the potentiometer
int potentVal;    // value of potentionmeter

void setup()
{
  Serial.begin(9600);
  steer.attach(9);  //attaches the steering servo on pin 9 to the servo object
  power.attach(8);  // attaches the power servo on pin 8 to the servo object
  power.write(180);
  
  pinMode(forwardBtn, INPUT_PULLUP); //taking forward button as input
  pinMode(backBtn, INPUT_PULLUP);    //taking backward button as input
}

void loop() 
{ 
  forwardBtnState = digitalRead(forwardBtn);  // read forward button state-- 1 or 0 
  backBtnState = digitalRead(backBtn);        // read backward button state-- 1 or 0
  if (forwardBtnState == HIGH && backBtnState == LOW) { //if forward button is pressed, and backward button is released
    power.write(180);
    delay(5);
  } else if (backBtnState == HIGH && forwardBtnState == LOW) {  //if backbutton is pressed and forwards button is released
    power.write(150);
    delay(5);
  } else {
    power.write(160);
    delay(5);
  }
  potentVal = analogRead(potpin);            // reads the value of the potentiometer (value between 0 and 1023) 
  potentVal = map(potentVal, 0, 1023, 60, 120);     // scale it to use it with the servo (value between 0 and 180) 
  steer.write(potentVal);                   //maps val to steering servo
  delay(5);                           // waits for the servo to get there 

}

Credits

Jessica Chang

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jessmchang.com

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Second Project Final Week

Second Project Final Week

Things used in this project

Hardware components

Story

Code

Knob-trial.ino

Credits

Jessica Chang

Comments