Sensor Si7021 with ESP8266

Updated on 3 September 2021
dev board WeMos D1 Mini
chip ESP8266
chip Si7021
sensor temperature
sensor humidity
This tutorial is more than 1 year old. If the steps below do not work, then please check the latest versions and the documentations of the individual tools used.

Before starting

Dependancies

Ensure the following dependancies are downloaded and available:

Buy the components

  1. WeMos D1 Mini
  2. Adafruit Si7021 board

Code

Download code sensor-si7021.ino 
#include "Adafruit_Si7021.h"

Adafruit_Si7021 sensor = Adafruit_Si7021();

void setup() {
  Serial.begin(115200);

  if (!sensor.begin()) {
    Serial.println("Did not find Si7021 sensor!");
    while (true) {}
  }
}

void loop() {
  Serial.print("Humidity:    ");
  Serial.print(sensor.readHumidity(), 2);
  Serial.print("\tTemperature: ");
  Serial.println(sensor.readTemperature(), 2);
  delay(1000);
}

Makefile

BOARD?=esp8266com:esp8266:d1_mini
PORT?=/dev/cu.wchusbserial1410

.PHONY: default lint all flash clean

default: lint all flash clean

lint:
	cpplint --extensions=ino --filter=-legal/copyright *.ino

all:
	arduino-cli compile --fqbn $(BOARD) ./

flash:
	arduino-cli upload -p $(PORT) --fqbn $(BOARD) ./

clean:
	rm -f .*.bin
	rm -f .*.elf

Schematic

Wire up the hardware accordingly

Sensor Si7021 with ESP8266 schematic

Description

Display humidity and temperature values with sensor Si7021 and ESP8266.

References

  1. Si7021 example code