🌡️ Sensor Calibration & Interpolation Tool

🎯 Getting Started

This tool helps you calibrate sensors that output analog voltages. By measuring known reference values (like temperatures or pressures) alongside their corresponding sensor voltages, you can create a calibration curve to convert any future voltage reading into physical units.

• Add calibration points: Enter raw voltage from your sensor and the corresponding reference value (measured with a calibrated instrument)
• Build a calibration curve: The tool performs linear regression to find the best-fit line ($y = mx + b$)
• Lookup unknown values: Type any raw voltage to instantly get the calculated physical value
• Analyze errors: View residuals to identify outliers and measurement uncertainty

📐 Linear Regression (Least Squares Method)

The tool uses the least squares method to find the calibration equation:

$y = mx + b$

Where:

• $y$: Physical value (temperature, pressure, etc.)
• $x$: Raw sensor value (voltage, ADC counts, etc.)
• $m$: Slope (conversion factor)
• $b$: Intercept (offset)

The slope $m$ and intercept $b$ are calculated to minimize the sum of squared residuals (errors).

📊 Error Analysis

Visualize how well your calibration points fit the regression line:

• Residuals: Vertical distance between each point and the regression line
• R² (Coefficient of Determination): Measures goodness of fit (0 to 1, closer to 1 is better)
• Standard Error: Average deviation of points from the line
• Outlier Detection: Points with large residuals may indicate measurement errors

💡 Tip: Collect more calibration points across your sensor's operating range for better accuracy

🔧 Example Use Cases

• Temperature Sensors: Calibrate thermistors or LM35 against a reference thermometer
• Pressure Sensors: Convert MPX4115A voltage output to kPa or PSI
• Load Cells: Map strain gauge voltage to weight (kg or lbs)
• Light Sensors: Convert photodiode voltage to lux or candela
• pH Sensors: Calibrate electrode voltage to pH values