Sensor basics: the numbers to look at in a datasheet

How a physical quantity becomes a voltage or data, and the range, resolution, accuracy and response speed you compare when choosing a sensor.

A sensor turns a physical quantity (temperature, acceleration, magnetic field, distance) into an electrical signal. There are three main kinds of output.

Output	Examples	MCU connection
Analog voltage	Thermistor divider, Hall current sensor	ADC
Digital communication	MPU6050, BME280, VL53L0X	I2C, SPI
Pulse / frequency	Encoder, ultrasonic echo, Hall switch	Timer capture, GPIO interrupt

Datasheet terms

Term	Meaning
Measurement range	±2 g, -40 to 125 °C
Resolution	The smallest change that can be distinguished
Accuracy	Difference from the true value (offset + gain error + non-linearity)
Sensitivity	Output per unit of the physical quantity (mV/g, LSB/°/s)
Noise density	µg/√Hz and the like. More bandwidth means more noise
Response time / ODR	How quickly and how often it gives a new value
Temperature drift	How much the offset changes with temperature

Resolution and accuracy are different

Resolution is how fine the scale is; accuracy is how far from the true value.

Even a 16-bit sensor is not accurate if its offset is large. Resolution is "how finely it divides" and accuracy is "how right it is". Most sensors get close to their datasheet accuracy only after calibration of the offset and gain.