How Temperature Sensors Work and How to Connect Them to Microcontrollers

Temperature sensors are used in many electronics projects, from simple monitoring systems to advanced control applications. In this project, we explore how three common types of temperature sensors work: RTDs, thermistors, and thermocouples. Each sensor has different characteristics, advantages, and ways of measuring temperature. We also demonstrate how to connect these sensors to a microcontroller using practical interface circuits such as voltage dividers and other signal conditioning methods. This tutorial combines theory and hands-on examples to help you understand how to measure temperature accurately and integrate these sensors into your own projects.

Mar 19, 2026

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3-Clause BSD License

Weather

Devices & Components

Breadboard - 840 contacts

16x2 LCD display with I²C interface

40 colored male-male jumper wires

THERMISTOR NTC 10KOHM 3950K DISC

RES 10K OHM 0.1% 1/4W AXIAL

CY8C58LP

Software & Tools

PSoC Creator 1

Project description

Code

Code for thermistor

This is the code

1#include "project.h"
2#include "math.h"
3#include "float.h"
4
5uint32 loop_counter, thermistor_R ;
6uint16 R_1_result, themistor_result ;
7int16  thermistor_mV, R_1_mV, temperature ;
8float  R_1_result_f, R_1_mV_f, thermistor_mV_f, ratio_f, voltage_f ;
9float  thermistor_RA_f, thermistor_RB_f ;
10float  current_mA_f, temperature_K_f ;
11
12int main(void)
13{
14    CyGlobalIntEnable;
15    
16    ADC_DelSig_1_Start() ;
17    AMux_1_Start() ;
18    
19    LCD_Start() ;
20    LCD_Position(0,0) ;
21    
22    DAC_Start() ;
23    
24    LCD_PrintString("Thermistor Test ") ;
25    CyDelay(1000) ;
26    
27    LCD_Position(0,0) ;
28
29    while(1)
30    {
31        P0_1_Write(1) ;       
32        CyDelay(100)  ;  
33        P0_1_Write(0) ; 
34        CyDelay(100)  ; 
35    
36        loop_counter++ ;  
37
38        AMux_1_Select(0) ;
39        ADC_DelSig_1_StartConvert() ;
40        ADC_DelSig_1_IsEndConversion(ADC_DelSig_1_WAIT_FOR_RESULT) ;
41    
42        P0_1_Write(0) ;   
43
44        R_1_result = ADC_DelSig_1_GetResult16() ;
45        R_1_result_f = (float)R_1_result ;
46
47        R_1_mV = (int16)ADC_DelSig_1_CountsTo_mVolts(R_1_result) ;
48        R_1_mV_f = (float)R_1_mV ;
49    
50        current_mA_f = R_1_mV_f / 10000. ;
51     
52        AMux_1_Select(1) ;
53        ADC_DelSig_1_StartConvert() ;
54        ADC_DelSig_1_IsEndConversion(ADC_DelSig_1_WAIT_FOR_RESULT) ;
55    
56        themistor_result = ADC_DelSig_1_GetResult16() ;
57    
58        thermistor_mV = (int16)ADC_DelSig_1_CountsTo_mVolts(themistor_result) ;
59    
60        thermistor_mV_f = (float)thermistor_mV ;  
61   
62        thermistor_RA_f = thermistor_mV_f / current_mA_f ;
63    
64        thermistor_R = Thermistor_1_GetResistance(R_1_mV, thermistor_mV) ;
65      
66        thermistor_RB_f = (float)thermistor_R ;
67 
68        temperature = Thermistor_1_GetTemperature(thermistor_R) ;
69    
70        DAC_SetValue( temperature - 2300 + 127 ) ;
71    
72        P0_0_Write(1) ;
73        LCD_IsReady() ;
74        LCD_Position(0,0) ;
75        LCD_PrintString("loop cnt:       ") ;
76        LCD_Position(0,10) ;      
77        LCD_PrintU32Number(loop_counter) ;
78        LCD_Position(1,0) ;
79
80        LCD_Position(1,0) ;
81        LCD_PrintString("         degrees ") ;
82        LCD_Position(1,0) ;
83        LCD_PrintNumber( temperature/100 ) ;   
84        LCD_Position(1,2) ;    
85        LCD_PrintString(".") ;     
86        LCD_PrintNumber( temperature%100 ) ;        
87        P0_0_Write(0) ;     
88    }
89}

#include "project.h"
#include "math.h"
#include "float.h"

uint32 loop_counter, thermistor_R ;
uint16 R_1_result, themistor_result ;
int16  thermistor_mV, R_1_mV, temperature ;
float  R_1_result_f, R_1_mV_f, thermistor_mV_f, ratio_f, voltage_f ;
float  thermistor_RA_f, thermistor_RB_f ;
float  current_mA_f, temperature_K_f ;

int main(void)
{
    CyGlobalIntEnable;
    
    ADC_DelSig_1_Start() ;
    AMux_1_Start() ;
    
    LCD_Start() ;
    LCD_Position(0,0) ;
    
    DAC_Start() ;
    
    LCD_PrintString("Thermistor Test ") ;
    CyDelay(1000) ;
    
    LCD_Position(0,0) ;

    while(1)
    {
        P0_1_Write(1) ;       
        CyDelay(100)  ;  
        P0_1_Write(0) ; 
        CyDelay(100)  ; 
    
        loop_counter++ ;  

        AMux_1_Select(0) ;
        ADC_DelSig_1_StartConvert() ;
        ADC_DelSig_1_IsEndConversion(ADC_DelSig_1_WAIT_FOR_RESULT) ;
    
        P0_1_Write(0) ;   

        R_1_result = ADC_DelSig_1_GetResult16() ;
        R_1_result_f = (float)R_1_result ;

        R_1_mV = (int16)ADC_DelSig_1_CountsTo_mVolts(R_1_result) ;
        R_1_mV_f = (float)R_1_mV ;
    
        current_mA_f = R_1_mV_f / 10000. ;
     
        AMux_1_Select(1) ;
        ADC_DelSig_1_StartConvert() ;
        ADC_DelSig_1_IsEndConversion(ADC_DelSig_1_WAIT_FOR_RESULT) ;
    
        themistor_result = ADC_DelSig_1_GetResult16() ;
    
        thermistor_mV = (int16)ADC_DelSig_1_CountsTo_mVolts(themistor_result) ;
    
        thermistor_mV_f = (float)thermistor_mV ;  
   
        thermistor_RA_f = thermistor_mV_f / current_mA_f ;
    
        thermistor_R = Thermistor_1_GetResistance(R_1_mV, thermistor_mV) ;
      
        thermistor_RB_f = (float)thermistor_R ;
 
        temperature = Thermistor_1_GetTemperature(thermistor_R) ;
    
        DAC_SetValue( temperature - 2300 + 127 ) ;
    
        P0_0_Write(1) ;
        LCD_IsReady() ;
        LCD_Position(0,0) ;
        LCD_PrintString("loop cnt:       ") ;
        LCD_Position(0,10) ;      
        LCD_PrintU32Number(loop_counter) ;
        LCD_Position(1,0) ;

        LCD_Position(1,0) ;
        LCD_PrintString("         degrees ") ;
        LCD_Position(1,0) ;
        LCD_PrintNumber( temperature/100 ) ;   
        LCD_Position(1,2) ;    
        LCD_PrintString(".") ;     
        LCD_PrintNumber( temperature%100 ) ;        
        P0_0_Write(0) ;     
    }
}

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