Posted by raghavchandra
Description:
The objective of this lab is to use a potentiometers (pots) as sensing devices. For this lab, we use potentiometers as inputs to the Arduino micro-controller to control LEDs, specifically their blinking and brightness. In this process, we explore the input features of our Arduino boards. We also learn how to solder wires.
Components Used:
- 3 LEDs(Red, Blue, Green)
- Arduino Micro-controller
- 3 Resistors (220 Ohms)
- Wires/Bread Board
- Solder Iron and Wire
- 3 Potentiometers ('pots')
- 'Helping Hands' (Clamps to hold the wires and pot in place while soldering)
Arduino Code: (Part of HW-Extra Credit)
Depending on the amount we rotate the nob of the potentiometer, two colors at a time are mixed. This creates a whole spectrum of colors by mixing green/blue, blue/red, and red/green. It also creates white light by mixing all three together.
(attached images give a few of the colors. Colors not very visible as the camera could not capture the glow)
Can use three pots; one for mixing color, one for increasing/decreasing the brightness and one for blinking. Using all three and playing around is a visual treat and creates a good light show!
/*
* -- (EXTRA CREDIT) --
* ### Using the ROTATION of a pot to create effect ###
* Depending on how much we rotate a pot, we can control which
* LED lights up. i.e. the rotation will rotate the brightness
* among the pots.
* Example:
* 0%: LED 1 HIGH only
* 0% to 25%: LED 1 dims while LED 2 brightens.
* 25%: LED 2 HIGH only.
* 25% to 50%: LED 2 dims while LED 3 brightens.
* 50%: LED 3 HIGH only
* 50% to 75%: LED 3 dims, while LED 1 brightens.
* after 75%: all LEDs have same brightness. (75% is HIGH, 100% is LOW)
*
* If we add 2nd and 3rd pot, one pot dims, the other pot changes the blinking rate
*
* modification of the following
* http://www.arduino.cc/en/Tutorial/AnalogInput
*/
/* UNCOMMENT if using additional pots(1,2) for blinking and dimming.
int pot1Pin = 0; // select the input pin for the potentiometer 1
int pot2Pin = 1; // select the input pin for the potentiometer 2
*/
int potRotPin = 2; // select the input pin for the potentiometer 3
int pot1Val = 0; // variable to store the value coming from pot 1
int pot2Val = 0; // variable to store the value coming from pot 2
int potRotVal = 0; // variable to store the value coming from pot 3
int led1Pin = 9; // select the pin for the LED 1
int led2Pin = 10; // select the pin for the LED 2
int led3Pin = 11; // select the pin for the LED 3
// values for each led to store their brightness depending on the amount
// the 'rotational effect' pot has been turned.
int led1Val = 0;
int led2Val = 0;
int led3Val = 0;
void setup() {
pinMode(led1Pin, OUTPUT); // declare the led1Pin as an OUTPUT
pinMode(led2Pin, OUTPUT); // declare the led2Pin as an OUTPUT
pinMode(led3Pin, OUTPUT); // declare the led3Pin as an OUTPUT
}
void loop() {
/* UNCOMMENT if using additional pots (1,2) for blinking and dimming
pot1Val = analogRead(pot1Pin); // read the value from pot 1, between 0 - 1024, for dimming
pot2Val = analogRead(pot2Pin); // read the value from pot 2, between 0 - 1024, for blinking
*/
//0(only 1), 255(only 2), 510(only 3), 765(all)
potRotVal = analogRead(potRotPin); // read the value from pot 2, between 0 - 1024, for 'Rotational effect'
// 0% to 25%
if (potRotVal >= 0 && potRotVal < 255) {
led1Val = 255 - potRotVal;
led2Val = 255 - led1Val;
led3Val = 0;
} // 25% to 50%
else if (potRotVal >= 255 && potRotVal < 510) {
led2Val = 255 - (potRotVal-255);
led3Val = 255 - led2Val;
led1Val = 0;
} // 50% to 75%
else if (potRotVal >= 510 && potRotVal < 765) {
led3Val = 255 - (potRotVal-510);
led1Val = 255 - led3Val;
led2Val = 0;
} // 75% to 100%
else if (potRotVal >= 765) {
led1Val = -255 + (potRotVal-765);
led2Val = -255 + (potRotVal-765);
led3Val = -255 + (potRotVal-765);
}
// -pot1Val/4 is for dimming using another pot.
analogWrite(led1Pin, led1Val - pot1Val/4); // dim LED 1 to value from pot1 and 3
analogWrite(led2Pin, led2Val - pot1Val/4); // dim LED 2 to value from pot1 and 3
analogWrite(led3Pin, led3Val - pot1Val/4); // dim LED 3 to value from pot1 and 3
// Below code is for Blinking using another pot.
/* UNCOMMENT if using a pot(pot 2) for Blinking.
delay(pot2Val); // stop the program for some time, meaning, LED is on for this time
analogWrite(led1Pin, 0); // dim LED 1 to completely dark (zero)
analogWrite(led2Pin, 0); // dim LED 2 to completely dark (zero)
analogWrite(led3Pin, 0); // dim LED 3 to completely dark (zero)
delay(pot2Val); // stop the program for some time, meaning, LED is OFF for this time
*/
}
