Week 2 Design Update

We decided to create a gun that is capable of firing rubber bands using a gear and an opposite end to hold the rubber bands. Each rubber band is held between the gear and the opposite end, and as the gear rotates, the rubber bands are released. Multiple rubber bands can be loaded onto the gun due to the multiple ridges on the gear.

Here are some examples that we decided to base our idea off of.

Rubber band gun example 1
http://www.pirate4x4.com/forum/general-chit-chat/845049-show-me-your-rubber-band-guns.html

Rubber band gun Example 2
http://www.doobybrain.com/2008/03/08/classic-rubber-band-launcher-on-dealextreme/

We wired up the Arduino Uno board with a servo motor, push button, LCD screen, and LED. We made the preliminary code featured below, but we plan to edit it so that the LCD screen, and possibly the LED, perform more advanced tasks. The push button will cause the servo motor to slightly rotate, which will in turn, rotate the gear causing the release of a rubber band. So far, the LCD screen and LED have constant displays, only to indicate that the mechanism is working properly.

	/* Code used to control servo motor with push button
	and display LCD and LED at all times
	*/
	#include <Servo.h>
	#include <LiquidCrystal.h>
	Servo Servo1;
	LiquidCrystal lcd(12,11,5,4,3,2);
	// global variables
	const int buttonPin = 8;
	boolean currentState = LOW;
	boolean lastState = LOW;
	boolean stateChange = false;
	int currentButton = 0;
	int lastButton = 4;
	int pos = 0;
	int led = 13;
	// LED and LCD constant display
	// setup
	void setup() {
	pinMode(buttonPin, INPUT);
	Serial.begin(9600);
	Servo1.attach(6);
	while (pos == lastButton);{
	pinMode(led, OUTPUT);
	lcd.begin(16, 2);
	lcd.clear();
	lcd.print("RBG");
	}
	}
	// set up push button
	// main loop
	void loop(){
	currentState = debounceButton();
	stateChange = checkForChange(currentState, lastState);
	currentButton = getButtonNumber(lastButton, currentState, stateChange);
	servoControl(currentButton);
	lastState = currentState;
	lastButton = currentButton;
	digitalWrite(led, HIGH);
	}
	// function debounceButton
	boolean debounceButton()
	{
	boolean firstCheck = LOW;
	boolean secondCheck = LOW;
	boolean current = LOW;
	firstCheck = digitalRead(buttonPin);
	delay(50);
	secondCheck = digitalRead(buttonPin);
	if (firstCheck == secondCheck){
	current = firstCheck;
	}
	return current;
	}
	// function checkForChange
	boolean checkForChange(boolean current, boolean last)
	{
	boolean change;
	if (current != last){
	change = true;
	}
	else {
	change = false;
	}
	return change;
	}
	// function getButtonNumber
	int getButtonNumber(int button, boolean state, boolean change)
	{
	if (change == true && state == LOW){
	button++;
	if (button > 4){
	button = 0;
	}
	Serial.println(button);
	}
	return button;
	}
	// Base servo position off of button state
	// function servoControl
	void servoControl(int button)
	{
	if(button == 0) {Servo1.write(10);}
	if(button == 1) {Servo1.write(30);}
	if(button == 2) {Servo1.write(50);}
	if(button == 3) {Servo1.write(70);}
	if(button == 4) {Servo1.write(90);}
	}

view raw gistfile1.txt hosted with ❤ by GitHub

The the push button brings the servo motor through five different positions. The LED remains on and the LCD constantly displays "RBG" for Rubber Band Gunners. Here is a video of the current code in action: