I am using hc-sr04 sensor for measuring height of liquid level continuously, but i find the sensitivity of sensor very bad. for example if i place object at 10cm the values it gives wud be around 9.4cm (which is kinda ok) but if i move object to 10.3 cm it gives around 12.1cm. Now how do i tackle this issue.
#include <WiFi.h>
#include <ESPAsyncWebServer.h>
#define TRIG_PIN 0 // G0
#define ECHO_PIN 1 // G1
const char* ssid = "TP-Link_2750";
const char* password = "84066107";
AsyncWebServer server(80);
bool recording = false;
String data = "";
void setup() {
Serial.begin(115200);
pinMode(TRIG_PIN, OUTPUT);
pinMode(ECHO_PIN, INPUT);
WiFi.begin(ssid, password);
Serial.print("Connecting to WiFi");
while (WiFi.status() != WL_CONNECTED) {
delay(1000);
Serial.print(".");
}
Serial.println();
Serial.println("Connected to WiFi");
Serial.print("IP Address: ");
Serial.println(WiFi.localIP());
server.on("/", HTTP_GET, [](AsyncWebServerRequest *request){
request->send(200, "text/html", R"rawliteral(
<!DOCTYPE HTML>
<html>
<head>
<title>ESP32 Distance Readings</title>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<script>
let recording = false;
let data = [];
function fetchReadings() {
fetch('/readings')
.then(response => response.text())
.then(readings => {
document.getElementById('readings').innerText = readings;
if (recording) {
let timestamp = new Date().toLocaleString();
data.push(`${timestamp},${readings}`);
}
});
}
function startRecording() {
recording = true;
data = [];
document.getElementById('status').innerText = "Recording...";
}
function stopRecording() {
recording = false;
document.getElementById('status').innerText = "Recording stopped";
}
function downloadData() {
let csvContent = "data:text/csv;charset=utf-8,Time,Distance (mm)\n" + data.join("\n");
let encodedUri = encodeURI(csvContent);
let link = document.createElement("a");
link.setAttribute("href", encodedUri);
link.setAttribute("download", "distance_readings.csv");
document.body.appendChild(link);
link.click();
}
setInterval(fetchReadings, 1000); // Fetch readings every second
</script>
</head>
<body>
<h1>ESP32 Distance Readings</h1>
<p id="readings">Loading...</p>
<p id="status">Not recording</p>
<button onclick="startRecording()">Start Recording</button>
<button onclick="stopRecording()">Stop Recording</button>
<button onclick="downloadData()">Download Data</button>
</body>
</html>
)rawliteral");
});
server.on("/readings", HTTP_GET, [](AsyncWebServerRequest *request){
long duration;
float distance;
digitalWrite(TRIG_PIN, LOW);
delayMicroseconds(2);
digitalWrite(TRIG_PIN, HIGH);
delayMicroseconds(10);
digitalWrite(TRIG_PIN, LOW);
duration = pulseIn(ECHO_PIN, HIGH);
distance = (duration / 2.0) * 0.343; // Convert to millimeters
String readings = String(distance) + " mm";
request->send(200, "text/plain", readings);
if (recording) {
String timestamp = String(millis() / 1000.0);
data += timestamp + "," + readings + "\n";
}
});
server.on("/start", HTTP_GET, [](AsyncWebServerRequest *request){
recording = true;
data = "";
request->send(200, "text/plain", "Recording started.");
});
server.on("/stop", HTTP_GET, [](AsyncWebServerRequest *request){
recording = false;
request->send(200, "text/plain", "Recording stopped.");
});
server.on("/download", HTTP_GET, [](AsyncWebServerRequest *request){
String csvContent = "data:text/csv;charset=utf-8,Time,Distance (mm)\n" + data;
request->send(200, "text/csv", csvContent);
});
server.begin();
Serial.println("Server started");
}
void loop() {
// No need to handle anything in the loop
}
This code saves and records the data thru wifi.
