arduino projects experiments part5

8/18/2019 Arduino Projects Experiments Part5

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Figure 9-4. The RGB Flasher Fritzing diagram

82 Make: Basic Arduino Projects


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Figure 9-6. The RGB Flasher built on a MakerShield

Example 9-1. The RGB Flasher sketch

/* RGB Flasher

Flashes the red, green, and blue LEDs of an RGB LED

Turns on an LED on for one second, then off for one second for each

color LED.

15 Feb 2013

Don Wilcher

*/

// RGB pins wired to the Arduino microcontroller.

// give them names:

int redled = 9;

int grnled = 10;

int bluled = 11;

// the setup routine runs once when you press reset:

void setup() {

// initialize the digital pins as outputs:

pinMode(redled, OUTPUT);

pinMode(grnled, OUTPUT);



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Something to Think AboutAre there common cathode RGB LEDs? If so, what Arduino microcontroller wiring

changes are needed to operate them correctly?



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Figure 10-2. The Magic Light Bulb Fritzing diagram

Upload the Magic Light Bulb SketchWith the Magic Light Bulb circuit built on the MakerShield, it’s time to upload the

sketch. Example 10-1 operates the RGB LEDs using a mini pushbutton switch. Here

are the steps you’ll need to follow:

1. Attach the Arduino to your computer using a USB cable.

2. Open the Arduino software and type Example 10-1 into the software’s texteditor.

3. Upload the sketch to the Arduino.

4. Press the mini pushbutton switch for a moment.

The Arduino will sequence the RGB LED tricolor pattern three times. Figure 10-3shows the Magic Light Bulb in action.

Chapter 10: The Magic Light Bulb 89


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Figure 10-3. The Magic Light Bulb running through the tricolor pattern

Example 10-1. The Magic Light Bulb sketch

/*

Magic Light Bulb

Flashes the red, green, and blue LEDs of an RGB LED three times by

briefly pressing a mini pushbutton switch.

25 Feb 2013 Don Wilcher

*/

// Pushbutton switch and RGB pins wired to the Arduino microcontroller.

// give them names:

int redled = 9;

int grnled = 10;

int bluled = 11;

int Pbutton = 8;

// initialize counter variable

int n =0;

// monitor pushbutton switch status:

int Pbuttonstatus = 0;

// the setup routine runs once when you press reset:void setup() {

// initialize the digital pins as outputs:

pinMode(redled, OUTPUT);

pinMode(grnled, OUTPUT);

pinMode(bluled, OUTPUT);

// initialize the digital pin as an input:



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Figure 10-5. The Magic Light Bulb circuit schematic diagram

Chapter 10: The Magic Light Bulb 93


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Figure 11-1. The Metal Checker device

Let’s Build a Metal Checker The Metal Checker is a cool electronics device to build with an Arduino and elec-

tronic parts from the Ultimate Microcontroller Pack. You can build the electronic

circuit on an ordinary breadboard or the MakerShield. Building the Metal Checker

on the MakerShield allows the device to fit nicely inside a Maker’s toolbox or work-

bench drawers. Also, the MakerShield is small enough to carry with you in the field

for scientific metal checking activities. Figure 11-2 provides a Fritzing diagram for

building the Metal Checker.



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The Arduino will turn on the piezo buzzer. Now you’re ready to unlock the metalmysteries hiding in your house!

Example 11-1. The Metal Checker sketch

/*

Metal Checker

Turns on and off a piezo buzzer at pin 7 when metal is placed across

the sense wires of the metal sensor circuit attached to pin 6.

The circuit:

* Piezo buzzer attached from pin 7 to ground

* Metal Checker sensor attached to pin 7

* 1KΩ fixed resistor attached from pin 6 to ground

March 2013

by Don Wilcher

*/

// set pin numbers:

const int MSensePin = 6; // the number of the metal sense pin

const int PBuzzerPin = 7; // the number of the piezo buzzer pin

// variables will change:

int MetalStatus = 0; // variable for the metal sense status

void setup() {

// initialize the LED pin as an output:

pinMode(PBuzzerPin, OUTPUT);

// initialize the pushbutton pin as an input:

pinMode(MSensePin, INPUT);

}

void loop(){

// read the state of the metal sense value:

MetalStatus = digitalRead(MSensePin);

// check if metal is present

// if it is, the MetalStatus is HIGH:

if (MetalStatus == HIGH) {

// turn piezo buzzer on:

digitalWrite(PBuzzerPin, HIGH);

}

else {

// turn MetalStatus off:

digitalWrite(PBuzzerPin, LOW);

}

}

Chapter 11: Metal Checker: The Electronic Switch 99


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