Hello.
I have an Arduino Uno and and ESP8266-01 module. I want to send data from a DHT11 sensor and a rain sensor, attached to the Arduino Uno to the ESP module via serial communication, and then to send them to HiveMQ Cloud. I don't get any prints in the serial monitor from the ESP, apart from the message "Hello World", which is also successfully sent to the topic in the cloud. I get the data readings from the Arduino correctly. I tried changing the baudrate as well, with no success. Here is the code:
Arduino code:
#include <DHT.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#define DHTPIN 7 // DHT11 sensor data pin
#define DHTTYPE DHT11 // DHT11 sensor type
#define RAIN_PIN 4 // Rain sensor pin
bool isRaining = false; // Flag to track rain status
DHT dht(DHTPIN, DHTTYPE);
// LCD configuration for I2C
LiquidCrystal_I2C lcd(0x27, 16, 2);
void setup() {
Serial.begin(9600); // Set baud rate to match ESP8266-01
lcd.init(); // Initialize LCD
lcd.backlight(); // Turn on backlight
dht.begin();
pinMode(RAIN_PIN, INPUT); // Set rain sensor pin as input
}
void loop() {
float humidity = dht.readHumidity();
float temperature = dht.readTemperature();
if (isnan(humidity) || isnan(temperature)) {
Serial.println("Failed to read from DHT sensor!");
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Sensor failure");
delay(2000);
return;
}
sendDataToESP(temperature, humidity, isRaining);
if (digitalRead(RAIN_PIN) == LOW) {
if (!isRaining) {
Serial.println("It's raining!");
isRaining = true; // Update rain status
sendDataToESP(temperature, humidity, isRaining); // Sending data to ESP8266
delay(1000);
}
Serial.print("Raining... \n");
} else {
if (isRaining) {
Serial.println("Rain stopped!");
isRaining = false; // Update rain status
sendDataToESP(temperature, humidity, isRaining); // Sending data to ESP8266
delay(1000);
}
}
Serial.print("Temperature: ");
Serial.print(temperature);
Serial.print(" *C, Humidity: ");
Serial.print(humidity);
Serial.println("%");
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Temp: ");
lcd.print(temperature);
lcd.print("C");
lcd.setCursor(0, 1);
lcd.print("Humidity: ");
lcd.print(humidity);
lcd.print("%");
delay(3000);
}
void sendDataToESP(float temp, float hum, bool rainStatus) {
Serial.print(temp);
Serial.print(",");
Serial.print(hum);
Serial.print(",");
Serial.println(rainStatus ? "Raining" : "Not Raining");
}
ESP8266-01 code:
/*
Basic sample of connecting ESP8266 with HiveMQ Cloud
- Time has to be obtained from NTP, because of CA expiration date validation.
It connects to HiveMQ Cloud broker then:
- Publishes "Hello World!" to the topic "testTopic" every two seconds.
- Subscribes to the topic "testTopic", printing out any messages (string payload) it receives.
It will reconnect to the server if the connection is lost using a blocking reconnect function.
*/
#include <ESP8266WiFi.h>
#include <PubSubClient.h>
#include <SoftwareSerial.h>
//---- WiFi settings
const char* ssid = "xxxxx";
const char* password = "xxxxx";
//---- HiveMQ Cloud Broker settings
const char* mqtt_server = "xxxxxxxxxxxx.s1.eu.hivemq.cloud";
const char* mqtt_user = "test123";
const char* mqtt_password = "xxxxxxx";
BearSSL::WiFiClientSecure espClient;
PubSubClient client(espClient);
SoftwareSerial arduinoSerial(2,3);
unsigned long lastMsg = 0;
#define MSG_BUFFER_SIZE (50)
char msg[MSG_BUFFER_SIZE];
int value = 0;
// HiveMQ Cloud Let's Encrypt CA certificate (hardcoded)
static const char ca_cert[] PROGMEM = R"EOF(
-----BEGIN CERTIFICATE-----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=
-----END CERTIFICATE-----
)EOF";
void setClock() {
configTime(2 * 3600, 0, "ro.pool.ntp.org", "time.nist.gov"); // Adjusted for Bucharest (EET: UTC+2)
Serial.print("Waiting for NTP time sync: ");
time_t now = time(nullptr);
while (now < 8 * 3600 * 2) {
delay(500);
Serial.print(".");
now = time(nullptr);
}
Serial.println("");
struct tm timeinfo;
localtime_r(&now, &timeinfo); // Use localtime_r for local time
Serial.print("Current time in Bucharest: ");
Serial.print(asctime(&timeinfo));
}
void setup_wifi() {
delay(10);
Serial.begin(9600);
// We start by connecting to a WiFi network
Serial.println();
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.mode(WIFI_STA);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
randomSeed(micros());
Serial.println("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
}
void callback(char* topic, byte* payload, unsigned int length) {
Serial.print("Message arrived [");
Serial.print(topic);
Serial.print("] ");
for (int i = 0; i < length; i++) {
Serial.print((char)payload[i]);
}
Serial.println();
}
void reconnect() {
char err_buf[256];
// Loop until we're reconnected
while (!client.connected()) {
Serial.print("Attempting MQTT connection...");
// MQTT client ID
String clientId = "ESP8266Client";
// Attempt to connect
if (client.connect(clientId.c_str(), mqtt_user, mqtt_password)) {
Serial.println("connected");
// Once connected, publish an announcement...
client.publish("testTopic", "Hello World!");
// ... and resubscribe
client.subscribe("testTopic");
} else {
Serial.print("failed, rc=");
Serial.println(client.state());
espClient.getLastSSLError(err_buf, sizeof(err_buf));
Serial.print("SSL error: ");
Serial.println(err_buf);
Serial.println(" try again in 5 seconds");
// Wait 5 seconds before retrying
delay(5000);
}
}
}
void setup() {
Serial.begin(9600);
arduinoSerial.begin(9600);
delay(5000);
BearSSL::X509List *serverTrustedCA = new BearSSL::X509List(ca_cert);
espClient.setTrustAnchors(serverTrustedCA);
setup_wifi();
setClock(); // Required for X.509 validation
client.setServer(mqtt_server, 8883);
client.setCallback(callback);
}
void loop() {
if (!client.connected()) {
reconnect();
}
client.loop();
//String dataArduino = arduinoSerial.readStringUntil('\n');
//arduinoSerial.println("DE LA ARDUINO");
while (arduinoSerial.available() > 0) {
String dataReceived = arduinoSerial.readStringUntil('\n');
Serial.print("Received data from Arduino: ");
Serial.println(dataReceived);
client.publish("testTopic", dataReceived.c_str());
}
}
The data readings from the Arduino are printed correctly in the serial monitor. The wirings are correct as well.
Any help is greatly appreciated!