Help me out with this code to measure the temperature using NTC 103 thermistor

[dikshakumarikangra07]

Not getting the accurate reading with this code. void loop() {
Vo = analogRead(A0);
Serial.print("ADC value :");
Serial.print(Vo);
R2 = R1 * (1023.0 / (float)Vo - 1.0);
Serial.print("Thermistor resistance: ");
Serial.println(R2 );
tKelvin = (Beta * roomTemp) / (Beta + (roomTemp * log(R2 / Ro)));
tCelsius = tKelvin - 273.15;
tFahrenheit = (tCelsius * 9.0) / 5.0 + 32.0;

[xfpd]

Can you show the readings you are getting, versus the readings you expect?
How do you read R1 and R2?
What will become of tCelsius, tFahrenheit, tKelvin, roomTemp, and Beta?

// must identify and "type" the variables
float Vo;
float Ro;
float R1;
float R2;
float tCelsius;
float tFahrenheit;
float tKelvin;
float roomTemp;
float Beta;

void setup() {
  Serial.begin(115200); // must start Serial communications at a (datarate)
}

void loop() {
  // Vo = analogRead(A0);
  Vo = map(analogRead(A0), 953, 115, 0, 100); // map NTC (953 low, 115 high) to positive numbers
  R2 = R1 * (1023.0 / Vo - 1.0);
  
  Serial.print("ADC value: ");
  Serial.print(Vo - 19.0); // adjust reading to range from -24.0 to +80.0
  Serial.print(" Thermistor resistance: ");
  Serial.println(R2);

  tKelvin = (Beta * roomTemp) / (Beta + (roomTemp * log(R2 / Ro)));
  tCelsius = tKelvin - 273.15;
  tFahrenheit = (tCelsius * 9.0) / 5.0 + 32.0;
  delay(2000);
}

ntc - Wokwi ESP32, STM32, Arduino Simulator

[johnerrington]

How do you have it connected? We need to know the way you are measuring the resistance, it makes a difference! Also the component values and A LINK to the exact thermistor you are using; eg

https://www.jameco.com/z/NTC-103-R-Jameco-ValuePro-Thermistor-NTC-K-10-10k-Ohm_207037.html

How to make a schematic you can post.

When you submit a question on the forum you will usually need to add a schematic (circuit diagram). The tutorial that follows will explain some ways to create a useful image; however lets start by explaining how to add the image to your post. Its easy. Having created the image all you need to do is : Save the image somewhere convenient - maybe your desktop Start your post, and place the cursor (insertion point) where you want the image to be shown; [upload image to forum] 3: click th…

[TomGeorge]

Hi,
Can you please post a circuit diagram so we can see how your NTC is connected?

What model Arduino are you using?

Thanks.. Tom..