Microcontroller sensor interfacing exercises

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Thermistor temperature sensor

• R₂₅ = 10000 Ohm, B = 3827 K
• output resistance range: 200 Ohm to 400000 Ohm

ADC

• Voltage reference: 2.048 V
• Number of bits: 16
• Jusfitication: right

Signal conditioning

• voltage divider - unknown resistance
• divider input voltage: 2.048 V
• reference resistance: 22000 Ohm
• resistor at GND: reference resistor

To do:

• Write a function that calculates the sensed value as a function of the ADC code!

Test data:

sensor input	sensor output	ADC input	ADC output	calculated sensor input
20 C	12447.4 Ohm	1.30796 V	41855	20.0002 C
129 C	361.72 Ohm	2.01487 V	64476	129.004 C
22 C	11393.6 Ohm	1.34924 V	43176	22.0005 C