Alternating LED's With Adjustable Frequency

Made for Mech 1 Mr. Sweets Class

Code comes from Arduino Example Library

Main circuit comes from sparksfun

1 Arduino Uno R3

1 Breadboard

1 potentiometer

1 PNP Transistor (2N3904)

2 LED's

3 100 ohm resistors

9 wires

//Coded in C++

int sensorPin = A0; // select the input pin for the potentiometer

int ledPin = 13; // select the pin for the LED

int sensorValue = 0; // variable to store the value coming from the sensor

void setup() {

// declare the ledPin as an OUTPUT:

pinMode(ledPin, OUTPUT);

}

void loop() {

// read the value from the sensor:

sensorValue = analogRead(sensorPin);

// turn the ledPin on

digitalWrite(ledPin, HIGH);

// stop the program for <sensorValue> milliseconds:

delay(sensorValue);

// turn the ledPin off:

digitalWrite(ledPin, LOW);

// stop the program for <sensorValue> milliseconds:

delay(sensorValue);

}

1) Connect the 5v pin to the positive lead on the breadboard and the ground pin to the negative lead

2) Place the potentiometer into the breadboard

3) The center pin of the potentiometer should be connected to any of the analog in pins (A 0-5), the left pin needs to be connected to negative and the right pin needs to be connected to positive

4) Place one of your LED's in the breadboard, wire the positive to pin 7 and place a resistor to ground

Wiring the PNP transistor

1) Place the PNP resistor in the bread board

2) Connect the Emitter pin to ground (The pinout from left to right, looking at the flat side is, Emitter Base Collector)

3) Connect the Collector to positive using a 100 ohm resistor

4) Connect the Collector to the LED positive lead

1) Connect the arduino 7 pin to the base pin of the LED