Write a program to read the potentiometer and display its value on the 4 LEDs.

a. The analogRead() function returns a value from 0 to 1023, a 10 bit number.

b. You have to convert the value to a 4 bit number and display it on the LEDs.

potentiometer code

// Constants and variables section

const int PotPin = A0; // input pin for the potentiometer

int PotReading = 0; // variable to hold potentiometer value

void setup()

{

Serial.begin(9600); // Opens the default serial channel at 9600 baud

}

void loop()

{

PotReading = analogRead(PotPin); // Read the pot

Serial.print("Potentiometer = "); // Beginning of message

Serial.print(PotReading); // potentiometer reading in decimal

Serial.print(" dec, "); // decimal indicator in message

Serial.print(PotReading, BIN); // potentiometer reading in binary

Serial.println(" bin"); // binary indicator in message, puts a linefeed at end

delay(200); //waits 200 msec for 5 Hz sampling rate

}

hint

1. Reducing a 10 bit number to a 4 bit number is the equivalent of dividing it by 64

2. You must look at each bit of your 4 bit number and use the bit value to turn on or off the appropriate

LED. (bit = 1, LED ON; bit = 0, LED OFF).

3. The following function allows you to determine the value of a particular bit in a binary number:

bit_value = bitRead(x, n);

x is the variable containing the binary number

n is the bit to be read, starting with bit 0 which is the least significant (rightmost) bit

bit_value is the variable that will contain the bit value returned by the bitRead( ) function, the

variable can have any name. It could be of type integer or char or boolean.

See the Arduino Language Reference for more details on this function.

Figure 7. 4 LED Output Circuit +5V 220 22 LED w 8's, MSB Arduino PWM 220 LED 6 M M 4's 22002 LED M 2's 2200 LED 1's, LSB LSB = Lease Significant Bit MSB = Most Significant Bit Potentiometer is connected to ANALOG IN pin AO as shown in Fig. 5