SENSORS/ACTUATORS

ESP32 MicroPython Temperature Sensor LCD

This tutorial instructs you how to use a ESP32 and MicroPython code to read the temperature from a DS18B20 temperature sensor and show it on an LCD I2C display.

Hardware Preparation

1	×	ESP-WROOM-32 Dev Module
1	×	USB Cable Type-C
1	×	LCD I2C
1	×	DS18B20 Temperature Sensor (WITH Adapter)
1	×	DS18B20 Temperature Sensor (WITHOUT Adapter)
1	×	Jumper Wires
1	×	(Recommended) Screw Terminal Expansion Board for ESP32

Or you can buy the following sensor kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables.

Overview of Temperature Sensor and LCD

If you're new to DS18B20 temperature sensor, LCD I2C, or MicroPython programming for the ESP32, I recommend checking out these tutorials:

These tutorials will provide you with a comprehensive understanding of DS18B20 temperature sensor and LCD, how to connect these components to the ESP32, and how to effectively control their behavior using MicroPython code.

Wiring Diagram

How to connect ESP32 with temperature sensor and lcd using breadboard

This image is created using Fritzing. Click to enlarge image

How to connect ESP32 with temperature sensor and lcd using screw terminal block breakout board

How to connect ESP32 with temperature sensor and lcd

This image is created using Fritzing. Click to enlarge image

ESP32 MicroPython Code

""" This ESP32 MicroPython code was developed by newbiely.com This ESP32 MicroPython code is made available for public use without any restriction For comprehensive instructions and wiring diagrams, please visit: https://newbiely.com/tutorials/esp32-micropython/esp32-micropython-temperature-sensor-lcd """ import machine import onewire import ds18x20 import time from machine import I2C, Pin from DIYables_MicroPython_LCD_I2C import LCD_I2C ds_pin = machine.Pin(23) # The ESP32 pin GPIO23 connected to the DS18B20 sensor # Create the onewire object OneWire = onewire.OneWire(ds_pin) # Create the DS18X20 object DS18B20 = ds18x20.DS18X20(OneWire) # Scan for devices on the bus sensor_addresses = OneWire.scan() if not sensor_addresses: raise Exception("No DS18B20 sensor found!") sensor_address = sensor_addresses[0] print('Found DS18B20 sensor with address: ', sensor_address) # The I2C address of your LCD (Update if different) I2C_ADDR = 0x27 # Use the address found using the I2C scanner # Define the number of rows and columns on your LCD LCD_ROWS = 2 LCD_COLS = 16 # Initialize I2C i2c = I2C(1, scl=Pin(22), sda=Pin(21), freq=400000) # Initialize LCD lcd = LCD_I2C(i2c, I2C_ADDR, LCD_ROWS, LCD_COLS) # Setup function lcd.backlight_on() lcd.clear() # Custom character for the degree symbol degree_char = chr(0xDF) # Main loop to read and print the temperature every second while True: DS18B20.convert_temp() time.sleep_ms(750) temperature = DS18B20.read_temp(sensor_address) print('Temperature: {:.2f} °C'.format(temperature)) lcd.clear() lcd.set_cursor(0, 0) # Move to the beginning of the first row lcd.print("Temp: {:.2f}{}C".format(temperature, degree_char)) time.sleep(1)

※ NOTE THAT:

Depending on the manufacturer, the I2C address for the LCD can vary. In our example, we used address 0x27 as specified by the manufacturer, DIYables.

Detailed Instructions

Here’s instructions on how to set up and run your MicroPython code on the ESP32 using Thonny IDE:

Make sure Thonny IDE is installed on your computer.
Confirm that MicroPython firmware is loaded on your ESP32 board.
If this is your first time using an ESP32 with MicroPython, check out the ESP32 MicroPython Getting Started guide for step-by-step instructions.
Connect the ESP32 board to the DS18B20 temperature sensor and LCD I2C according to the provided diagram.
Connect the ESP32 board to your computer with a USB cable.
Open Thonny IDE on your computer.
In Thonny IDE, go to Tools Options.
Under the Interpreter tab, choose MicroPython (ESP32) from the dropdown menu.
Make sure the correct port is selected. Thonny IDE usually detects it automatically, but you might need to select it manually (like COM12 on Windows or /dev/ttyACM0 on Linux).
Navigate to the Tools Manage packages on the Thonny IDE.
Search “DIYables-MicroPython-LCD-I2C”, then find the LCD I2C library created by DIYables.
Click on DIYables-MicroPython-LCD-I2C, then click Install button to install LCD I2C library.

Copy the provided MicroPython code and paste it into Thonny's editor.
Save the code to your ESP32 by:

Clicking the Save button or pressing Ctrl+S.
In the save dialog, choose MicroPython device.
Name the file main.py.

Click the green Run button (or press F5) to execute the script.

Shell x

>>> %Run -c $EDITOR_CONTENT

MPY: soft reboot MPY: soft reboot Found DS18B20 sensor with address: bytearray(b'(\xffP\x05.\x04\x00\x07') Temperature: 26.07 °C Temperature: 26.11 °C Temperature: 26.11 °C Temperature: 26.24 °C Temperature: 27.44 °C Temperature: 29.10 °C Temperature: 29.86 °C Temperature: 30.24 °C Temperature: 30.39 °C

MicroPython (ESP32) • CP2102 USB To UART Bridge Controller @ COM12 ≡

Put the sensor on hot or cold water, or hold it in your hand.
Look at the display on the LCD screen.

If the LCD screen is blank, please visit Troubleshooting for LCD I2C for help.

Code Explanation

Look at the comments in the source code for explanations of each line!

Video Tutorial

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