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May 18, 2015 AT 5:23 pm

NEW TUTORIAL: Calibrating Sensors

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NEW TUTORIAL: Calibrating Sensors

Why do we need to calibrate sensors?

There are a lot of good sensors these days and many are ‘good enough’ out of the box for many non-critical applications. But in order to achieve the best possible accuracy, a sensor should be calibrated in the system where it will be used. This is because:

  • No sensor is perfect.
    • Sample to sample manufacturing variations mean that even two sensors from the same manufacturer production run may yield slightly different readings.
    • Differences in sensor design mean two different sensors may respond differently in similar conditions. This is especially true of ‘indirect’ sensors that calculate a measurement based on one or more actual measurements of some different, but related parameter.
    • Sensors subject to heat, cold, shock, humidity etc. during storage, shipment and/or assembly may show a change in response.
    • Some sensor technologies ‘age’ and their response will naturally change over time – requiring periodic re-calibration.
  • The Sensor is only one component in the measurement system. For example:
    • With analog sensors, your ADC is part of the measurement system and subject to variability as well.
    • Temperature measurements are subject to thermal gradients between the sensor and the measurement point.
    • Light and color sensors can be affected by spectral distribution, ambient light, specular reflections and other optical phenomena.
    • Inertial sensors are sensitive to alignment with the system being measured

What makes a good sensor?

The two most important characteristic of a sensor are:

  • Precision – The ideal sensor will always produce the same output for the same input.
  • Resolution – A good sensor will be able to reliably detect small changes in the measured parameter.

See the full tutorial here!


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