[TLV493D] Method to calibrate temperature offset

tlv493d/tlv493d.go

@@ -30,6 +30,9 @@ const (
 	HighPrecisionWithTemperature Precision = 0
 	// LowPrecision reads only 8-bits for each axis. Temperature is not read.
 	LowPrecision Precision = 1
+	// DefaultTemperatureOffsetCompensation is the temperature offset compensation used by default, following the documentation advices.
+	// For accurate results, please calibrate it using CalibrateTemperatureOffsetCompensation method.
+	DefaultTemperatureOffsetCompensation = 340
 )
 
 const (
@@ -137,7 +140,7 @@ var DefaultOpts = Opts{
 	EnableTemperatureMeasurement:  true,
 	InterruptPadEnabled:           false,
 	ParityTestEnabled:             true,
-	TemperatureOffsetCompensation: 340, // As per the documentation, can be calibrated for better precision
+	TemperatureOffsetCompensation: DefaultTemperatureOffsetCompensation, // As per the documentation, can be calibrated for better precision
 }
 
 // Sample contains the metrics measured by the sensor
@@ -422,6 +425,18 @@ func (d *Dev) StopContinousRead() {
 	d.continuousReadWG.Wait()
 }
 
+// CalibrateTemperatureOffsetCompensation computes the temperature offset compensation based upon a reading from the sensor compared to the actual temperature.
+// The returned value must be stored and passed in Opts.TemperatureOffsetCompensation in future uses of TLV493D driver.
+// See TLV493D user manual, "3.2 Calculation of the temperature" for more information
+func CalibrateTemperatureOffsetCompensation(temperatureOffsetCompensation int, measuredTemperature physic.Temperature, actualTemperature physic.Temperature) int {
+	// Compute measurement based upon reference documentation
+	rawTemp := int((measuredTemperature-referenceTemperature)/temperatureScaling) + temperatureOffsetCompensation
+	// Compute the new offset by matching the raw measurement between the measure and the actual value
+	newOffset := rawTemp - int((actualTemperature-referenceTemperature)/temperatureScaling)
+
+	return newOffset
+}
+
 func bestModeForFrequency(frequency physic.Frequency) (Mode, error) {
 
 	allowed := []*Mode{&FastMode, &LowPowerMode, &UltraLowPowerMode}

tlv493d/tlv493d_test.go

@@ -326,6 +326,17 @@ func TestTLV493D_Configuration(t *testing.T) {
 	}
 }
 
+func Test_TLV493D_TemperatureCalibration(t *testing.T) {
+	measure := 25*physic.Celsius + physic.ZeroCelsius
+	actual := 19*physic.Celsius + physic.ZeroCelsius
+	offset := CalibrateTemperatureOffsetCompensation(DefaultTemperatureOffsetCompensation, measure, actual)
+	expectedOffset := 345
+
+	if offset != expectedOffset {
+		t.Fatalf("Temperature offset: Found %d, expected %d", offset, expectedOffset)
+	}
+}
+
 func assertSample(t *testing.T, expected Sample, actual Sample) {
 	if actual.Bx != expected.Bx {
 		t.Fatalf("Bx: Found %d, expected %d", actual.Bx, expected.Bx)