MENGATUR INTENSITAS CAHAYA LED PADA ESP32
Pada praktikum kali ini board yang digunakan adalah ESP32, ESP32 sendiri sudah dilengkapi dengan WiFI dan bluetoth sebagai pengirim ataupun penerima data.
Mengatur intensitas cahaya led sangatlah mudah cukup dengan memanfaatkan PWM. PWM ( Pulse Width Modulation) sendiri adalah salah satu teknik modulasi dengan mengubah lebar pulsa (duty cylce) dengan nilai amplitudo dan frekuensi yang tetap. Satu siklus pulsa merupakan kondisi high kemudian berada di zona transisi ke kondisi low. Lebar pulsa PWM berbanding lurus dengan amplitudo sinyal asli yang belum termodulasi. Duty Cycle merupakan representasi dari kondisi logika high dalam suatu periode sinyal dan di nyatakan dalam bentuk (%) dengan range 0% sampai 100%, sebagai contoh jika sinyal berada dalam kondisi high terus menerus artinya memiliki duty cycle sebesar 100%. Jika waktu sinyal keadaan high sama dengan keadaan low maka sinyal mempunyai duty cycle sebesar 50%.
Alat dan bahan yang dibutuhkan pada praktikum kali ini adalah :
Sketch Program:
*SSID dan PASSWORD sesuaikan dengan yang anda gunakan.
Setelah selesai menuliskan kode pada Arduino IDE, kemudian pilih board ESP32 dan sesuaikan port yang digunakan selanjutnya upload Sketch Program, tunggu hingga proses upload selesai dan buka serial monitor pilih range 115200 baud.
Jika serial monitor yang ditampilkan kosong, tekan EN (enable) pada board ESP32
Pada gambar di atas terlihat IP address, IP adress merupakan local link website yang akan digunakan untuk mengatur intensitas cahaya pada led.
Itulah percobaan mengatur intensitas cahaya led pada board ESP32.
Mengatur intensitas cahaya led sangatlah mudah cukup dengan memanfaatkan PWM. PWM ( Pulse Width Modulation) sendiri adalah salah satu teknik modulasi dengan mengubah lebar pulsa (duty cylce) dengan nilai amplitudo dan frekuensi yang tetap. Satu siklus pulsa merupakan kondisi high kemudian berada di zona transisi ke kondisi low. Lebar pulsa PWM berbanding lurus dengan amplitudo sinyal asli yang belum termodulasi. Duty Cycle merupakan representasi dari kondisi logika high dalam suatu periode sinyal dan di nyatakan dalam bentuk (%) dengan range 0% sampai 100%, sebagai contoh jika sinyal berada dalam kondisi high terus menerus artinya memiliki duty cycle sebesar 100%. Jika waktu sinyal keadaan high sama dengan keadaan low maka sinyal mempunyai duty cycle sebesar 50%.
Alat dan bahan yang dibutuhkan pada praktikum kali ini adalah :
- Board ESP32
- Arduino IDE
- Kabel USB untuk menghubungkan board dengan komputer
- LED yang digunakan LED yang sudah tertanam di board ESP32
 |
ESP32 Board |
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| #include <WiFi.h> | |
| //#include "style.css" | |
| // GPIO the LED is attached to | |
| static const int ledPin = 2; | |
| // Setting PWM properties | |
| const int freq = 5000; | |
| const int ledChannel = 0; | |
| const int resolution = 8; | |
| int dutyCycle = 0; | |
| // Replace with your network credentials | |
| const char* ssid = "SSID"; | |
| const char* password = "PASS"; | |
| // Set web server port number to 80 | |
| WiFiServer server(80); | |
| // Variable to store the HTTP request | |
| String header; | |
| // Decode HTTP GET value | |
| String valueString = String(5); | |
| int pos1 = 0; | |
| void setup() { | |
| // Configure LED PWM functionalitites | |
| ledcSetup(ledChannel, freq, resolution); | |
| // Attach the channel to the GPIO to be controlled | |
| ledcAttachPin(ledPin, ledChannel); | |
| Serial.begin(115200); | |
| // Connect to Wi-Fi network with SSID and password | |
| Serial.print("Connecting to "); | |
| Serial.println(ssid); | |
| WiFi.begin(ssid, password); | |
| while (WiFi.status() != WL_CONNECTED) { | |
| delay(500); | |
| Serial.print("."); | |
| } | |
| // Print local IP address and start web server | |
| Serial.println(""); | |
| Serial.println("WiFi connected."); | |
| Serial.println("IP address: "); | |
| Serial.println(WiFi.localIP()); | |
| server.begin(); | |
| } | |
| void loop(){ | |
| WiFiClient client = server.available(); // Listen for incoming clients | |
| if (client) { // If a new client connects, | |
| Serial.println("New Client."); // print a message out in the serial port | |
| String currentLine = ""; // make a String to hold incoming data from the client | |
| while (client.connected()) { // loop while the client's connected | |
| if (client.available()) { // if there's bytes to read from the client, | |
| char c = client.read(); // read a byte, then | |
| Serial.write(c); // print it out the serial monitor | |
| header += c; | |
| if (c == '\n') { // if the byte is a newline character | |
| // if the current line is blank, you got two newline characters in a row. | |
| // that's the end of the client HTTP request, so send a response: | |
| if (currentLine.length() == 0) { | |
| // HTTP headers always start with a response code (e.g. HTTP/1.1 200 OK) | |
| // and a content-type so the client knows what's coming, then a blank line: | |
| client.println("HTTP/1.1 200 OK"); | |
| client.println("Content-type:text/html"); | |
| // client.println("Access-Control-Allow-Origin:*"); | |
| client.println("Connection: close"); | |
| client.println(); | |
| // Display the HTML web page | |
| client.println("<!DOCTYPE html><html>"); | |
| client.println("<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">"); | |
| client.println("<link rel=\"icon\" href=\"data:,\">"); | |
| // client.println("<link rel=\"stylesheet\" href=\"https://raw.githubusercontent.com/Erhylk/digitalent2/master/Coding/ESP32_PwmSlider/style.css\" type=\"text/css\">"); | |
| client.println("<style>*{margin:0;padding:0}body{background:#009688;color:#efefef;text-shadow:2px 1px orange;width:100vw;height:100vh;display:flex;flex-direction:column;align-items:center;justify-content:center;font-family:\"Trebuchet MS\",Arial}.slider{margin-top:10px;width:300px;-webkit-appearance:none;height:10px;border-radius:5px;background:#d3d3d3;outline:0;-webkit-transition:.2s;transition:opacity .2s;opacity:.9;box-shadow:0 2px 2px rgba(9,9,9,.3)}.slider::-webkit-slider-thumb{-webkit-appearance:none;appearance:none;width:30px;height:30px;border-radius:50%;border:4px solid orange;background:#ff0;cursor:pointer;box-shadow:0 2px 2px rgba(9,9,9,.3)}.slider::-moz-range-thumb{width:30px;height:30px;border-radius:50%;border:4px solid orange;background:#ff0;cursor:pointer;box-shadow:0 2px 2px rgba(9,9,9,.3)}h1,p,svg{padding:8px 5px}svg{fill:#000;width:100px;height:100px}path.led{fill:#ff0}</style>"); | |
| client.println("<script src=\"https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js\"></script>"); | |
| // Web Page | |
| client.println("</head><body>"); | |
| client.println("<svg height=\"512pt\" viewBox=\"-56 0 512 512\" width=\"512pt\" xmlns=\"http://www.w3.org/2000/svg\"><g fill-rule=\"evenodd\"><path d=\"m139.089844 366.472656h122.46875v84.96875c-6.160156 28.914063-31.234375 50.558594-61.234375 50.558594-30.003907 0-55.078125-21.644531-61.234375-50.558594zm0 0\" fill=\"#67e5dd\"/><path d=\"m200.324219 74.585938c69.441406 0 125.738281 56.292968 125.738281 125.738281 0 87.078125-63.90625 115.398437-63.90625 152.617187 0 4.78125-.207031 9.285156-.601562 13.53125h-122.464844c-.390625-4.246094-.597656-8.75-.597656-13.53125 0-37.21875-63.90625-65.539062-63.90625-152.617187 0-69.445313 56.292968-125.738281 125.738281-125.738281zm0 0\" fill=\"#fec96b\" class=\"led\"/><path d=\"m200.324219 64.585938c-58.6875 0-110.484375 37.414062-128.898438 93.101562-1.734375 5.242188 1.113281 10.898438 6.355469 12.632812 5.246094 1.734376 10.902344-1.109374 12.632812-6.355468 15.699219-47.480469 59.867188-79.378906 109.910157-79.378906 63.816406 0 115.738281 51.917968 115.738281 115.738281 0 49.324219-22.09375 78.792969-39.84375 102.472656-12.914062 17.222656-24.066406 32.101563-24.066406 50.144531 0 1.191406-.015625 2.363282-.042969 3.53125h-41.785156v-22.972656c0-5.523438-4.476563-10-10-10-5.523438 0-10 4.476562-10 10v22.972656h-41.789063c-.027344-1.167968-.042968-2.34375-.042968-3.53125 0-18.046875-11.152344-32.921875-24.0625-50.148437-13.074219-17.441407-27.894532-37.210938-35.242188-65.300781-1.398438-5.34375-6.863281-8.542969-12.203125-7.144532-5.34375 1.398438-8.542969 6.863282-7.144531 12.207032 8.339844 31.886718 25.109375 54.257812 38.585937 72.234374 11.210938 14.957032 20.066407 26.773438 20.066407 38.152344 0 4.789063.203124 9.464844.597656 13.917969v84.585937c0 .269532.019531.53125.042968.792969.003907.066407 0 .128907.007813.195313.035156.367187.09375.730468.167969 1.085937.003906.003907.003906.003907.003906.007813 3.46875 16.289062 12.359375 31.101562 25.039062 41.707031 12.921876 10.8125 29.25 16.765625 45.972657 16.765625 16.722656 0 33.046875-5.953125 45.972656-16.765625 12.675781-10.605469 21.570313-25.417969 25.039063-41.707031 0-.003906.003906-.007813.003906-.011719.074218-.355469.128906-.714844.167968-1.085937.003907-.0625.003907-.128907.007813-.191407.019531-.265625.039063-.527343.039063-.796875v-84.582031c.394531-4.457031.601562-9.128906.601562-13.917969 0-11.382812 8.855469-23.195312 20.066406-38.152344 18.5-24.679687 43.839844-58.476562 43.839844-114.464843 0-74.847657-60.890625-135.738281-135.738281-135.738281zm-51.234375 354.371093h102.46875v22.484375h-102.46875zm102.46875-20h-102.46875v-22.484375h102.46875zm-51.234375 93.042969c-20.332031 0-38.667969-12.296875-47.355469-30.558594h94.710938c-8.691407 18.261719-27.027344 30.558594-47.355469 30.558594zm0 0\"/><path d=\"m200.324219 46.644531c5.523437 0 10-4.476562 10-10v-26.644531c0-5.523438-4.476563-10-10-10-5.523438 0-10 4.476562-10 10v26.644531c0 5.523438 4.476562 10 10 10zm0 0\" class=\"led\"/><path d=\"m36.644531 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7.070313-2.929687l18.839843-18.839844c3.90625-3.90625 3.90625-10.234375 0-14.140625s-10.238281-3.90625-14.140624 0zm0 0\" class=\"led\"/><path d=\"m316.0625 94.585938c2.558594 0 5.117188-.976563 7.070312-2.929688l18.839844-18.839844c3.90625-3.90625 3.90625-10.238281 0-14.144531-3.902344-3.90625-10.234375-3.902344-14.140625 0l-18.839843 18.839844c-3.90625 3.90625-3.90625 10.238281-.003907 14.144531 1.953125 1.953125 4.515625 2.929688 7.074219 2.929688zm0 0\" class=\"led\"/><path d=\"m330.03125 315.890625c-3.902344-3.90625-10.234375-3.90625-14.140625 0-3.90625 3.902344-3.90625 10.234375 0 14.140625l18.839844 18.839844c1.953125 1.953125 4.511719 2.929687 7.070312 2.929687 2.558594 0 5.117188-.976562 7.070313-2.929687 3.90625-3.902344 3.90625-10.234375 0-14.140625zm0 0\" class=\"led\"/><path d=\"m390.644531 190.324219h-26.644531c-5.523438 0-10 4.476562-10 10 0 5.523437 4.476562 10 10 10h26.644531c5.523438 0 10-4.476563 10-10 0-5.523438-4.476562-10-10-10zm0 0\" class=\"led\"/><path d=\"m200.324219 283.5c-5.507813 0-10 4.492188-10 10s4.492187 10 10 10c5.507812 0 10-4.492188 10-10s-4.492188-10-10-10zm0 0\" class=\"led\"/><path d=\"m74.585938 210.324219c5.507812 0 10-4.492188 10-10 0-5.507813-4.492188-10-10-10-5.511719 0-10 4.492187-10 10 0 5.507812 4.488281 10 10 10zm0 0\" /></g></svg>"); | |
| client.println("<h1>ESP32 with PWM</h1>"); | |
| client.println("<p>Position: <span id=\"pwmPos\"></span></p>"); | |
| client.println("<input type=\"range\" min=\"0\" max=\"255\" class=\"slider\" id=\"ledSlider\" onchange=\"pwm(this.value)\" value=\""+valueString+"\"/>"); | |
| client.println("<script>const slider = document.getElementById(\"ledSlider\");"); | |
| client.println("const pwmP = document.getElementById(\"pwmPos\"); pwmP.innerHTML = slider.value;"); | |
| client.println("slider.value = 0;"); | |
| client.println("slider.oninput = function() { slider.value = this.value; pwmP.innerHTML = this.value; }"); | |
| client.println("$.ajaxSetup({timeout:1000}); function pwm(pos) { "); | |
| client.println("$.get(\"/?value=\" + pos + \"&\"); {Connection: close};}</script>"); | |
| client.println("</body></html>"); | |
| //GET /?value=180& HTTP/1.1 | |
| if(header.indexOf("GET /?value=")>=0) { | |
| pos1 = header.indexOf('='); | |
| valueString = header.substring(pos1+1); | |
| dutyCycle = valueString.toInt(); | |
| ledcWrite(ledChannel, dutyCycle); | |
| Serial.println(valueString); | |
| } | |
| // The HTTP response ends with another blank line | |
| client.println(); | |
| // Break out of the while loop | |
| break; | |
| } else { // if you got a newline, then clear currentLine | |
| currentLine = ""; | |
| } | |
| } else if (c != '\r') { // if you got anything else but a carriage return character, | |
| currentLine += c; // add it to the end of the currentLine | |
| } | |
| } | |
| } | |
| // Clear the header variable | |
| header = ""; | |
| // Close the connection | |
| client.stop(); | |
| Serial.println("Client disconnected."); | |
| Serial.println(""); | |
| } | |
| } |
*SSID dan PASSWORD sesuaikan dengan yang anda gunakan.
Setelah selesai menuliskan kode pada Arduino IDE, kemudian pilih board ESP32 dan sesuaikan port yang digunakan selanjutnya upload Sketch Program, tunggu hingga proses upload selesai dan buka serial monitor pilih range 115200 baud.
 |
Serial Monitor COM7 |
 |
WiFi Terhubung |
Salin alamat IP address kemudian tempelkan di browser yang akan kalian gunakan, kemdian enter atau Go, pada praktikum ini terlihat IP address yaitu 192.168.43.112 sesuaikan dengan IP yang tampil pada serial monitor kalian.
Setelah IP address dibuka pada browser maka akan muncul tampilan seperti ini
Pada awal tampilan posisi slider menunjukkan 0 artinya led pada board mati
 |
Led Biru Mati |
Selanjutnya atur atau geser slide bar ke posisi 36, terlihat seperti gambar dibawah
Terlihat bahwa led pada board menyala dengan intensitas 36%
 |
Led biru menyala dengan rentang 36 |
Selanjutnya coba geser slider hingga penuh rentang 255, seperti gambar
Led biru pada board menyala lebih terang dari sebelumnya,
 |
Led biru dengan rentang 255 |
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