Microcontroller sensor interfacing exercises

---

Thermistor temperature sensor

• R₂₅ = 4700 Ohm, B = 4405 K
• output resistance range: 200 Ohm to 400000 Ohm

ADC

• Voltage reference: 2.5 V
• Number of bits: 10
• Jusfitication: right

Signal conditioning

• voltage divider - unknown resistance
• divider input voltage: 2.5 V
• reference resistance: 33000 Ohm

To do:

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

Test data:

sensor input	sensor output	ADC input	ADC output	calculated sensor input
56 C	1168.92 Ohm	2.41448 V	989	56.0225 C
45 C	1856.68 Ohm	2.36683 V	969	44.7982 C
-5 C	24544.6 Ohm	1.43367 V	587	-5.01507 C