I want to use my ESP32 DEVKITC V4 with my soil moisture sensor this one and ESP NOW.
So my goal is to have multiple ESP32 modules with a soil moisture senor that sends data to one ESP32 module using ESP NOW where i can monitor the data.
Here is the circuit diagram:
And here is the code for the sensor, which works fine:
int moisture, sensor_analog;
const int sensor_pin = A0; /* Soil moisture sensor O/P pin */
void setup(void) {
Serial.begin(115200); /* Set the baudrate to 115200*/
}
void loop(void) {
sensor_analog = analogRead(sensor_pin);
moisture = (100 - ((sensor_analog / 4095.00) * 100));
Serial.print("Moisture = ");
Serial.print(moisture); /* Print Temperature on the serial window */
Serial.println("%");
delay(1000); /* Wait for 1000mS */
}
And here is the code that i tried using but the sender keeps restarting when i plug my sensor in:
/*********
Rui Santos
Complete project details at https://RandomNerdTutorials.com/esp-now-many-to-one-esp32/
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files.
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
*********/
#include <esp_now.h>
#include <WiFi.h>
int sensor_analog;
const int sensor_pin = A0; /* Soil moisture sensor O/P pin */
// REPLACE WITH THE RECEIVER'S MAC Address
uint8_t broadcastAddress[] = {0x34, 0x85, 0x18, 0x8C, 0xB6, 0x0C};
// Structure example to send data
// Must match the receiver structure
typedef struct struct_message {
int id; // must be unique for each sender board
int moisture;
String text;
} struct_message;
// Create a struct_message called readings
struct_message readings;
// Create peer interface
esp_now_peer_info_t peerInfo;
// callback when data is sent
void OnDataSent(const uint8_t *mac_addr, esp_now_send_status_t status) {
Serial.print("\r\nLast Packet Send Status:\t");
Serial.println(status == ESP_NOW_SEND_SUCCESS ? "Delivery Success" : "Delivery Fail");
}
void setup() {
// Init Serial Monitor
Serial.begin(115200);
// Set device as a Wi-Fi Station
WiFi.mode(WIFI_STA);
// Init ESP-NOW
if (esp_now_init() != ESP_OK) {
Serial.println("Error initializing ESP-NOW");
return;
}
// Once ESPNow is successfully Init, we will register for Send CB to
// get the status of Trasnmitted packet
esp_now_register_send_cb(OnDataSent);
// Register peer
memcpy(peerInfo.peer_addr, broadcastAddress, 6);
peerInfo.channel = 0;
peerInfo.encrypt = false;
// Add peer
if (esp_now_add_peer(&peerInfo) != ESP_OK){
Serial.println("Failed to add peer");
return;
}
}
void loop() {
// Set values to send
sensor_analog = analogRead(sensor_pin);
readings.id = 1;
readings.moisture = (100 - ((sensor_analog / 4095.00) * 100));
if(readings.moisture < 35) {
readings.text = "The plant needs to be watered!";
}
// Send message via ESP-NOW
esp_err_t result = esp_now_send(broadcastAddress, (uint8_t *) &readings, sizeof(readings));
if (result == ESP_OK) {
Serial.println("Sent with success");
}
else {
Serial.println("Error sending the data");
}
delay(1000);
}
And here is the code for the receiver, which works fine:
/*********
Rui Santos
Complete project details at https://RandomNerdTutorials.com/esp-now-many-to-one-esp32/
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files.
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
*********/
#include <esp_now.h>
#include <WiFi.h>
// Structure example to receive data
// Must match the sender structure
typedef struct struct_message {
int id; // must be unique for each sender board
int moisture;
String text;
} struct_message;
// Create a struct_message called readings
struct_message readings;
// Create a structure to hold the readings from each board
struct_message board1;
struct_message board2;
struct_message board3;
// Create an array with all the structures
struct_message boardsStruct[3] = { board1, board2, board3 };
// callback function that will be executed when data is received
void OnDataRecv(const uint8_t *mac_addr, const uint8_t *incomingData, int len) {
char macStr[18];
Serial.print("Packet received from: ");
snprintf(macStr, sizeof(macStr), "%02x:%02x:%02x:%02x:%02x:%02x",
mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
Serial.println(macStr);
memcpy(&readings, incomingData, sizeof(readings));
Serial.printf("Board ID %u: %u bytes\n", readings.id, len);
// Update the structures with the new incoming data
boardsStruct[readings.id - 1].moisture = readings.moisture;
boardsStruct[readings.id - 1].text = readings.text;
Serial.printf("Moisture level: %d% \n", boardsStruct[readings.id - 1].moisture);
Serial.printf("Message: %s \n", boardsStruct[readings.id - 1].text);
Serial.println();
}
void setup() {
//Initialize Serial Monitor
Serial.begin(115200);
//Set device as a Wi-Fi Station
WiFi.mode(WIFI_STA);
//Init ESP-NOW
if (esp_now_init() != ESP_OK) {
Serial.println("Error initializing ESP-NOW");
return;
}
// Once ESPNow is successfully Init, we will register for recv CB to
// get recv packer info
esp_now_register_recv_cb(OnDataRecv);
}
void loop() {
// Acess the variables for each board
/*int board1X = boardsStruct[0].x;
int board1Y = boardsStruct[0].y;
int board2X = boardsStruct[1].x;
int board2Y = boardsStruct[1].y;
int board3X = boardsStruct[2].x;
int board3Y = boardsStruct[2].y;*/
delay(10000);
}
Any help will be appreciated. Thanks 
.