Published February 26, 2023

Basic RP2040 room temperature display

A small, simple, and easy to use, room temperature sensor. It measures and displays temperature on an SSD1306 LCD. All powered by a battery

BeginnerShowcase (no instructions)488

Things used in this project

Hardware components

Seeed Studio Seeed XIAO RP2040

Story

This project is about building your own room temperature display with the Xiao RP2040 from Seeed Studios. The Xiao series of MCU's are small packaged but they pack a punch!! This project relies heavily on the Xiao RP2040 as it consumes little power, has great accuracy thanks to the RP2040 microprocessor, and a cost effective price of under $6. There are more processor variants available like, ESP C3, and Realtek!!

A HUGE thanks to Seeed Studios, for sponsoring this project!!

Go check them out on https://www.seeedstudio.com/

There you can buy your own devices from Seeed and even get yourself your very own Xiao RP2040!! https://www.seeedstudio.com/XIAO-c-1964.html

For more information about their amazing PCBA and PCB manufacturing service:

https://www.seeedstudio.com/fusion.html

Unfortunately, by not paying enough attention. I have placed a 10k resistor, instead of a 4.7k on the NTC. Be sure to change that resistor with a 10k pot and adjust it accordingly to 4.7k. You can hide it under the oled display and adjust it for more accuracy.

Thanks to the art of programming, over time you might want to let it turn on a fan or a light depending on temperature, then all you need to do is solder on some wires to the Xiao and connect them to another expansion device to better break out those pins.

The battery has to manually be connected via a diode and a wire from B+ to 3.3v pin on the Seeed Xiao. With the diode only allowing current to flow to the MCU. Otherwise you will blow it to smoke!

The programming Tutorial!!

https://wiki.seeedstudio.com/XIAO-RP2040-with-Arduino/

Code

Xiao RP2040 room temperature display

// In this sketch the temperature is displayed in degrees Celcius
//
//

#include <SPI.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_GFX.h>  //https://github.com/adafruit/Adafruit-GFX-Library
#include <OneWire.h>
#include <DallasTemperature.h>   //https://github.com/milesburton/Arduino-Temperature-Control-Library
#define ONE_WIRE_BUS 10

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

float previousTemp = -100.0;
float tempC = 0;

#define UI_BMPWIDTH  128

const unsigned char bitmap_ui[] PROGMEM = {
  0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, // ################################################################################################################################
  0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, // ################################################################################################################################
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x7F,0x80,0x00,0x00,0x00,0x00,0x00,0xC0,0x00,0x00,0x00,0x00,0x03, // ##.......................########...............................................##............................................##
  0xC0,0x00,0x00,0x7F,0x80,0x00,0x00,0x00,0x00,0x00,0xC0,0x00,0x00,0x00,0x00,0x03, // ##.......................########...............................................##............................................##
  0xC0,0x00,0x00,0x0C,0x1E,0x7D,0xC7,0xC3,0xCF,0x3D,0xF6,0x6F,0x3C,0x00,0x00,0x03, // ##..........................##.....####..#####.###...#####....####..####..####.#####.##..##.####..####........................##
  0xC0,0x00,0x00,0x0C,0x3F,0x7F,0xE7,0xE7,0xEF,0x7E,0xC6,0x6F,0x7E,0x00,0x00,0x03, // ##..........................##....######.##########..######..######.####.######.##...##..##.####.######.......................##
  0xC0,0x00,0x00,0x0C,0x33,0x66,0x66,0x66,0x6C,0x06,0xC6,0x6C,0x66,0x00,0x00,0x03, // ##..........................##....##..##.##..##..##..##..##..##..##.##.......##.##...##..##.##...##..##.......................##
  0xC0,0x00,0x00,0x0C,0x3F,0x66,0x66,0x67,0xEC,0x3E,0xC6,0x6C,0x7E,0x00,0x00,0x03, // ##..........................##....######.##..##..##..##..##..######.##....#####.##...##..##.##...######.......................##
  0xC0,0x00,0x00,0x0C,0x30,0x66,0x66,0x66,0x0C,0x66,0xC6,0x6C,0x60,0x00,0x00,0x03, // ##..........................##....##.....##..##..##..##..##..##.....##...##..##.##...##..##.##...##...........................##
  0xC0,0x00,0x00,0x0C,0x31,0x66,0x66,0x66,0x2C,0xE6,0xC6,0x6C,0x62,0x00,0x00,0x03, // ##..........................##....##...#.##..##..##..##..##..##...#.##..###..##.##...##..##.##...##...#.......................##
  0xC0,0x00,0x00,0x0C,0x3F,0x66,0x67,0xE7,0xEC,0x7E,0xF7,0xEC,0x7E,0x00,0x00,0x03, // ##..........................##....######.##..##..##..######..######.##...######.####.######.##...######.......................##
  0xC0,0x00,0x00,0x0C,0x1E,0x66,0x67,0xC3,0xCC,0x7E,0x73,0xEC,0x3C,0x00,0x00,0x03, // ##..........................##.....####..##..##..##..#####....####..##...######..###..#####.##....####........................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x06,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##...................................................##.......................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x06,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##...................................................##.......................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x06,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##...................................................##.......................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03, // ##............................................................................................................................##
  0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, // ################################################################################################################################
  0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF  // ################################################################################################################################
};

void setup() {
  Serial.begin(9600);
  Serial.println("Starting up ...");
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  sensors.begin();
  display.clearDisplay();
  display.drawBitmap(0,0,bitmap_ui, 128,64, SSD1306_WHITE);
  display.setTextSize(2);             // Normal 1:1 pixel scale
  display.setTextColor(SSD1306_WHITE);        // Draw white text
  display.setCursor(80,30);             // Start at top-left corner
  display.println((char)247 );
  display.setCursor(95,30); 
  display.println("C");
  display.display();
}

void loop() {
    delay(1000);
    previousTemp = tempC;
    sensors.requestTemperatures();
    tempC = sensors.getTempCByIndex(0); 
    Serial.println(tempC);
    if(previousTemp!=tempC)
    {
       deletePreviousTemperature();
       printTemperature();
    }
}

void printTemperature()
{
  display.setTextSize(2);             
  display.setCursor(25,30);  
  display.setTextColor(SSD1306_WHITE);         
  display.println(tempC,1);
  display.display();
}

void deletePreviousTemperature()
{
  display.setTextSize(2);             
  display.setCursor(25,30); 
  display.setTextColor(SSD1306_BLACK);                     
  display.println(previousTemp,1);
  display.display();
}

Credits

Dieter

4 projects • 3 followers

Hi Im a 17 Year old student working on electronics and DIY projects. I hope you enjoy my content!!

Thanks to Seeed Studios and Educ8s.

Basic RP2040 room temperature display

Things used in this project

Hardware components

Story

Schematics

SCHEMATICS AND GREBERS!!

Code

Xiao RP2040 room temperature display

Credits

Dieter

Comments

Embed the widget on your own site

Basic RP2040 room temperature display

Basic RP2040 room temperature display

Things used in this project

Hardware components

Story

Schematics

SCHEMATICS AND GREBERS!!

Code

Xiao RP2040 room temperature display

Credits

Dieter

Comments

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