7.2 Room Temperature Meter

Using a thermistor and an I2C LCD1602, we can create a room temperature meter.

This project is very simple, it is based on 2.13 Thermometer with I2C LCD1602 to display the temperature.

Schematic

Wiring

Code

Note

• Open the 7.2_room_temperature_meter.py file under the path of euler-kit/micropython or copy this code into Thonny, then click “Run Current Script” or simply press F5 to run it.

• Don’t forget to click on the “MicroPython (Raspberry Pi Pico)” interpreter in the bottom right corner.

• For detailed tutorials, please refer to Open and Run Code Directly.

from lcd1602 import LCD
import machine
import utime
import math

thermistor = machine.ADC(28)
lcd = LCD()

while True:
    temperature_value = thermistor.read_u16()
    Vr = 3.3 * float(temperature_value) / 65535
    Rt = 10000 * Vr / (3.3 - Vr)
    temp = 1/(((math.log(Rt / 10000)) / 3950) + (1 / (273.15+25)))
    Cel = temp - 273.15
    #Fah = Cel * 1.8 + 32
    #print ('Celsius: %.2f C  Fahrenheit: %.2f F' % (Cel, Fah))
    #utime.sleep_ms(200)

    string = " Temperature is \n    " + str('{:.2f}'.format(Cel))+ " C"
    lcd.message(string)
    utime.sleep(1)
    lcd.clear()

The LCD will display the temperature value in the current environment after the program runs.

Note

If the code and wiring are fine, but the LCD still does not display content, you can turn the potentiometer on the back to increase the contrast.