In this post, we see how to make this easy Arduino Ohmmeter Circuit using Arduino UNO and 16×2 LCD. Here, you can see the Tinkercad interactive simulation and you can also try this circuit in physical components.
LED NEON FLEX:
https://micromonitor.myshopify.com/
First, we see the circuit components:
- Arduino UNO Amazon UK , Banggood
- 16×2 LCD Amazon UK , Banggood
- Reference Resistor 1 K Ohm
- Unknown Resistor
- Jumper wires
Circuit Connections:
We can see the Circuit Connections in the video and Tinkercad Simulation.
Arduino UNO connected to 16×2 LCD using four pins of data. Enable pin and register select pins connected to Arduino read/write.
Contrast pin connected to ground. Vcc and ground of the LCD connected to Vcc and ground of Arduino. The backlight led connected to Vcc the negative terminal of the backlight led connected to the ground through one kilo ohm resistor.
The unknown resistor connected to five volts of the Arduino and A0 analog input pin. The reference resistor 1 kilo ohm used to make a voltage divider circuit connected to the ground and A0 pin.
This voltage divider circuit measures the input voltage to pin A0 and using the voltage divider formula we can determine the unknown resistor value.
Circuit works using voltage divider connection. The two resistors ( known and unknown ) form a voltage divider that enables you to determine the value of the unknown resistor using the value of the voltage.
Code:
#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
int analogPin= 0;
int raw= 0;
int Vin= 5;
float Vout= 0;
float R1= 1000;
float R2= 0;
float buffer= 0;
void setup()
{
lcd.begin(16, 2);
}
void loop()
{
raw= analogRead(analogPin);
if(raw)
{
buffer= raw * Vin;
Vout= (buffer)/1024.0;
buffer= (Vin/Vout) -1;
R2= R1 * buffer;
lcd.setCursor(0, 0);
lcd.print("Vout: ");
lcd.print(Vout);
lcd.setCursor(0, 1);
lcd.print("R2: ");
lcd.print(R2);
delay(1000);
}
}
We start by including the LCD library then defining the LCD pins and defining the variables analog input pin A0.
The reference resistor value is 1 kilo ohm and the unknown resistor variable we start by reading the analog input voltage to pin A0 then using the voltage divider formula to know the unknown resistor value. Then print that value on the LCD.
Conclusion:
You can make a simple Arduino Ohmmeter circuit using Arduino UNO, 16×2 LCD and some resistors.
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