I want to send data between ESP-32(NODEMCU-32S) and arduino uno but I haven't found any source on how to do that so I tried this code
ESP-32 code:
#include <WiFi.h>
#include <Wire.h>
String ClientRequest;
IPAddress staticIP850_244(192,168,137,244);
IPAddress gateway850_244(192,168,137,1);
IPAddress subnet850_244(255,255,255,0);
WiFiServer server(80);
WiFiClient client;
String myresultat;
String ReadIncomingRequest(){
while(client.available()) {
ClientRequest = (client.readStringUntil('\r'));
if ((ClientRequest.indexOf("HTTP/1.1")>0)&&(ClientRequest.indexOf("/favicon.ico")<0)){
myresultat = ClientRequest;
}
}
return myresultat;
}
void setup()
{
ClientRequest = "";
Serial.begin(9600);
Wire.begin(21, 22); /* join i2c bus with SDA=D1 and SCL=D2 of NodeMCU */
WiFi.disconnect();
WiFi.begin("test","12345678");
while ((!(WiFi.status() == WL_CONNECTED))){
delay(300);
}
WiFi.config(staticIP850_244, gateway850_244, subnet850_244);
server.begin();
}
void loop()
{
client = server.available();
if (!client) { return; }
while(!client.available()){ delay(1); }
ClientRequest = (ReadIncomingRequest());
ClientRequest.remove(0, 5);
ClientRequest.remove(ClientRequest.length()-9,9);
if (ClientRequest == "ON") {
Wire.beginTransmission(8); /* begin with device address 8 */
Wire.write(1); /* sends hello string */
Serial.println("sent on");
Wire.endTransmission(); /* stop transmitting */
}
else if (ClientRequest == "OFF") {
Wire.beginTransmission(8); /* begin with device address 8 */
Wire.write(2); /* sends hello string */
Serial.println("sent off");
Wire.endTransmission(); /* stop transmitting */
}
else if (ClientRequest == "AUTO") {
Wire.beginTransmission(8); /* begin with device address 8 */
Wire.write(3); /* sends hello string */
Serial.println("sent auto");
Wire.endTransmission(); /* stop transmitting */
}
client.flush();
Wire.requestFrom(8, 18); /* request & read data of size 13 from slave */
while(Wire.available()){
int c = Wire.read();
Serial.print(c);
client.println("HTTP/1.1 200 OK");
client.println("Content-Type: text/html");
client.println("");
client.println("<!DOCTYPE HTML>");
client.println("<html>");
client.println(c);
client.println("</html>");
}
}
and arduino code:
#include <Wire.h>
#define pump1 4
#define pump2 5
#define PWM 3
#define LDR A0
#define moisture_sensor A1
byte statusLed = 13;
byte sensorInterrupt = 0; // 0 = digital pin 2
byte sensorPin = 2;
// The hall-effect flow sensor outputs approximately 4.5 pulses per second per
// litre/minute of flow.
float calibrationFactor = 4.5;
volatile byte pulseCount;
float flowRate;
unsigned int flowMilliLitres;
unsigned long totalMilliLitres;
unsigned long oldTime;
boolean automatic;
void setup() {
Wire.begin(8); /* join i2c bus with address 8 */
Wire.onReceive(receiveEvent); /* register receive event */
Wire.onRequest(requestEvent); /* register request event */
Serial.begin(9600); /* start serial for debug */
// Set up the status LED line as an output
pinMode(statusLed, OUTPUT);
digitalWrite(statusLed, HIGH); // We have an active-low LED attached
pinMode(sensorPin, INPUT);
digitalWrite(sensorPin, HIGH);
pulseCount = 0;
flowRate = 0.0;
flowMilliLitres = 0;
totalMilliLitres = 0;
oldTime = 0;
// The Hall-effect sensor is connected to pin 2 which uses interrupt 0.
// Configured to trigger on a FALLING state change (transition from HIGH
// state to LOW state)
attachInterrupt(sensorInterrupt, pulseCounter, FALLING);
}
void loop() {
if (automatic){
int moisture_level = map(analogRead(moisture_sensor), 0, 1023, 100, 0); //scale the reading 100% to 0%
int LDR_reading = map(analogRead(LDR), 0, 1023, 0, 100); //scale the reading 100% to 0%
if (moisture_level < 60 && LDR_reading < 85) {
digitalWrite(pump1, HIGH);
digitalWrite(pump2, LOW);
analogWrite(PWM,255);
}
else {
digitalWrite(pump1, LOW);
digitalWrite(pump2, LOW);
analogWrite(PWM,0);
}
}
}
// function that executes whenever data is received from master
void receiveEvent(int howMany) {
while (0 <Wire.available()) {
int c = Wire.read(); /* receive byte as a character */
Serial.print(c); /* print the character */
if (c == 3) {
Serial.println("auto mode");
automatic = true;
}
else if (c == 1) {
digitalWrite(pump1, HIGH);
digitalWrite(pump2, LOW);
analogWrite(PWM, 255);
Serial.println();
Serial.print("turned on");
automatic = false;
}
else if (c == 2) {
digitalWrite(pump1, LOW);
digitalWrite(pump2, LOW);
Serial.println();
Serial.print("turned off");
Serial.println();
automatic = false;
}
}
Serial.println(); /* to newline */
}
// function that executes whenever data is requested from master
void requestEvent() {
if((millis() - oldTime) > 1000) // Only process counters once per second
{
// Disable the interrupt while calculating flow rate and sending the value to
// the host
detachInterrupt(sensorInterrupt);
// Because this loop may not complete in exactly 1 second intervals we calculate
// the number of milliseconds that have passed since the last execution and use
// that to scale the output. We also apply the calibrationFactor to scale the output
// based on the number of pulses per second per units of measure (litres/minute in
// this case) coming from the sensor.
flowRate = ((1000.0 / (millis() - oldTime)) * pulseCount) / calibrationFactor;
// Note the time this processing pass was executed. Note that because we've
// disabled interrupts the millis() function won't actually be incrementing right
// at this point, but it will still return the value it was set to just before
// interrupts went away.
oldTime = millis();
// Divide the flow rate in litres/minute by 60 to determine how many litres have
// passed through the sensor in this 1 second interval, then multiply by 1000 to
// convert to millilitres.
flowMilliLitres = (flowRate / 60) * 1000;
// Add the millilitres passed in this second to the cumulative total
totalMilliLitres += flowMilliLitres;
unsigned int frac;
// Print the flow rate for this second in litres / minute
// Serial.print("Flow rate: ");
// Serial.print(int(flowRate)); // Print the integer part of the variable
// Serial.print("."); // Print the decimal point
//Determine the fractional part. The 10 multiplier gives us 1 decimal place.
frac = (flowRate - int(flowRate)) * 10;
// Serial.print(frac, DEC) ; // Print the fractional part of the variable
// Serial.print("L/min");
// // Print the number of litres flowed in this second
// Serial.print(" Current Liquid Flowing: "); // Output separator
// Serial.print(flowMilliLitres);
// Serial.print("mL/Sec");
// Print the cumulative total of litres flowed since starting
Serial.print(" Output Liquid Quantity: "); // Output separator
Serial.print(totalMilliLitres);
Serial.println("mL");
// Reset the pulse counter so we can start incrementing again
pulseCount = 0;
// Enable the interrupt again now that we've finished sending output
attachInterrupt(sensorInterrupt, pulseCounter, FALLING);
}
Wire.write("we need irrigation");
}
but I found that no data was sent
I connected pin 21 to A4 and 22 to A5 directly.
I cannot find where the problem is.
also, I don't know whether the device address is correct or not since when I tried an i2c scanner it didn't discover any device.
Also, I hope if there is a similar method to have two way UART communication between the arduino and esp as I found none since I need both chips to send data to each other.
