OLED + Temperature Sensor on Espruino (JavaScript on MCU)

Two short examples of reading temperature by DS18B20 or DHT22 sensor and show it on OLED display (4-wire SPI) or (2-wire I2C).

Everything is wired directly with breadboard wires to the Espruino Pico board.

No external power supply needed.
Just Plugin to USB Port or power by USB battery pack.

>> source on GitHub

Hardware

• SPI OLED display (aliexpress)
• Temperature sensor ([aliexpress)

Wiring OLED display

| OLED | Pico |  
| ---- |------| 
| GND  | A5   | 
| VCC  | A7   | 
| SCL  | B5   | 
| SDA  | B6   | 
| RST  | B7   | 
| D/C  | A8   | 

Wiring DS18B20 temperature sensor

| DS18B20 | Pico | 
| ------- |------|
| GND     | GND  | 
| OUT     | A6   | 
| VCC     | VDD  | 

Initialize OLED display

var spi = new SPI(); 
spi.setup({mosi: B6, sck:B5}); 
// OLED driver and graphic library 
var g = require("SSD1306").connectSPI(spi, A8, B7, function() {
   // display is connected...   
   // do something  
}); 

Initialize DS18B20 temperature sensor

// Analog pin A6 to read temperature from Dallas DS18B20 sensor 
// temp sensor is powered by pins VDD and GND of pico 
var ow = new OneWire(A6); 
var tempSensor = require("DS18B20").connect(ow);

Read temperature

var temperature = tempSensor.getTemp(); 
console.log("Temp is "+temperature);

>> source on GitHub

Hardware

• I2C OLED display ([aliexpress)
• Temperature sensor (aliexpress)

Wiring OLED display

| OLED | Pico |  
| ---- |------| 
| GND  | A5   | 
| VCC  | A7   | 
| SDL  | B6   | 
| SDA  | B7   |   

Wiring DHT22 temperature sensor

| DHT22   | Pico |  
| ------- |------| 
| 1: VCC  | VDD  | 
| 2: DATA | A8   | 
| 3: N/C  | N/C  | 
| 4: GND  | GND  | 

> N/C = not connected 

Initialize OLED display

I2C1.setup({scl:B6,sda:B7}); 
// OLED driver and graphic library 
var g = require("SSD1306").connect(I2C1, function() {
   // display is connected...
   // do something  
});

Initialize DHT22 temperature sensor

// Analog pin A8 to read temperature from DHT22 sensor 
// temp sensor is powered by pins VDD and GND of pico 
var tempSensor = require("DHT22").connect(A8);

Read temperature

var temperature; 
var humidity; 
tempSensor.read(function(dht) {
   temperature = dht.temp;
   humidity = dht.rh;
   console.log("Temp is "+temperature.toString()+" and RH is "+humidity.toString());
});