Calibrating a temperature sensor using an Arduino code

Calibrating a temperature sensor using an Arduino code involves the following steps:

1. Connect your temperature sensor to your Arduino board.

2. Write the Arduino code to read the temperature from the sensor. You can use the built-in libraries in Arduino IDE to read the temperature from various sensors, such as the DS18B20, LM35, or DHT11 sensors.

3. Once you have the temperature reading, you can compare it to a known temperature reading to calibrate your sensor. For example, you can place your temperature sensor in a container of ice water and measure the temperature. The temperature of ice water should be around 0 degrees Celsius or 32 degrees Fahrenheit. If your sensor is not reading the correct temperature, you can adjust the code to compensate for the difference.

4. Another way to calibrate your sensor is to place it in boiling water and measure the temperature. The temperature of boiling water should be around 100 degrees Celsius or 212 degrees Fahrenheit. Again, if your sensor is not reading the correct temperature, you can adjust the code to compensate for the difference.

5. Once you have calibrated your temperature sensor, you can use it to measure the temperature in other environments. Make sure to take into account any calibration adjustments you made to the code when using the sensor in other settings.

One Point Calibration

One point calibration is the simplest type of calibration. If the sensor output is already scaled to useful measurement units, a one point calibration can be used to correct for sensor offset errors in the following cases:

• Only one measurement point is needed. If you have an application that only requires accurate measurement of a single level, there is no need to worry about the rest of the measurement range.  An example might be a temperature control system that needs to maintain the same temperature continuously.
• The sensor is known to be linear and have the correct slope over the desired measurement range. In this case, it is only necessary to calibrate one point in the measurement range and adjust the offset if necessary.  Many temperature sensors are good candidates for one-point calibration.

A one point calibration can also be used as a "drift check" to detect changes in response and/or deterioration in sensor performance.  

For example, thermocouples used at very high temperatures exhibit an 'aging' effect.  This can be detected by performing periodic one point calibrations, and comparing the resulting offset with the previous calibration.

How to do it:

To perform a one point calibration:

1. Take a measurement with your sensor.
2. Compare that measurement with your reference standard.
3. Subtract the sensor reading from the reference reading to get the offet.
4. In your code, add the offset to every sensor reading to obtain the calibrated value

cal_factor is my offset value of Arduino code,