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How to build a Arduino Robocar Part 1

I've been meaning to put some content on here for a while and recently I got around to getting an Uno and motor shield. Given I also have access to a 3d printer and have a shedload of microswitches, semis and other goodies knocking around - Robocar is an obvious choice!

I've had a few Arduino's in the past but have always used them as an ISP to write to AVR instead of just embracing the Arduino eco-system. I'm over that nonsense now and will be learning as I go.

The Plan

A four-wheeled car type thingy which drives two rear wheels and steers with two front wheels.

For starters, I want to make it go forward until it hits an obstacle detected by a front-left & front-right µswitch-bumper system. At that point, it will reverse/turn around 90 degrees and go forward again.

The Parts

(so far)
IMG_0646%255B1%255D_84b59faab6587dc9265054879e4cff65391594be.jpg

 

The Code

I've hacked together some of the example sketches from the Arduino IDE to get a small motor to run when input A5 on the Uno goes high.

// Adafruit Motor shield library
// copyright Adafruit Industries LLC, 2009
// this code is public domain, enjoy!
#include 

AF_DCMotor motor(4);
const int buttonPin = A5;    // the number of the pushbutton pin

// variables will change:
int buttonState = 0;        // variable for reading the pushbutton status


  if (buttonState == HIGH) {
 // turn on motor
  motor.setSpeed(200);
 
  motor.run(FORWARD);}
else {
  motor.setSpeed(0);
 
  motor.run(RELEASE);
  }
}

It works almost as expected although the motor runs for about 7 seconds then stops. I have no idea why at this stage - Surely the loop isn't taking 7 seconds to run and there's no time value in there. I'd expect it to ONLY run when the pin is high.

I'm off to figure that out and think about the 3d printed body/wheels/steering mechanics.

Stay tuned for part 2.....

Comments/suggestions/things you would like to see me attempt and then explain etc.... Are encouraged so please just shout.

Stuart.

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