Activity 3. Analog to Digital Converter

This activity uses the Arduino Uno's built-in analog-to-digital converter. (50 minutes)

Activity 3a

In this part the aim is for the Arduino Uno to:

  • read the analog voltage of a potentiometer
  • send it to serial communication
  • a voltmeter has been added to the circuit to check the voltage of the potentiometer


Step 1. Draw the next circuit in Tinkercad.


 


Step 2. Study the code and write it on the microcontroller:

/* ADC and serial

Circuit connections:
Potensiometer_Terminal_1 => Gnd
Potensiometer_Wiper => A0
Potensiometer_Terminal_2 => Vcc

PIN_0 => Serial_RX
PIN_1 => Serial_TX
*/

#define pot_pin A0     //give the name “pot_pin” to PIN_A0
//variable to save data from ADC
int adc_value; //number range 0~1023
float voltage;  //variable to calculate the analog voltage 

//The setup() function initializes and sets the initial values
//It will only run once after each power up or reset
void setup() {
  Serial.begin(9600);
}

//This function loops consecutively
void loop() {
//read analog voltage and convert to number
adc_value = analogRead(pot_pin);
//calculate the analog voltage from adc_number 
voltage = float(adc_value)/1023*5;
//print to serial the adc_number and the analog voltage
Serial.print("ADC number: "); 
Serial.println(adc_value);
Serial.print("Voltage = ");
Serial.print(voltage);
Serial.println("V");
//wait for 5 seconds
delay(5000);
}

Step 3. Run the simulation and check the correct operation of the circuit