Description

Micro_Drone

I designed and built a custom flight controller PCB for multirotor drones, starting from schematic design to PCB layout and testing. The board integrates a microcontroller, an IMU with accelerometer and gyroscope, onboard voltage regulation, and motor/ESC signal outputs in a compact form factor. It processes real-time sensor data to estimate orientation and stabilize the drone using control algorithms such as PID. The PCB was designed with careful attention to power integrity, grounding, decoupling, and low-noise signal routing to ensure accurate sensor readings and reliable performance. Standard communication interfaces like I²C, SPI, and UART are provided for sensor communication, configuration, and debugging. This project demonstrates complete end-to-end hardware development and practical understanding of embedded systems, control systems, and PCB design for flight-critical applications.

Code

C/C++

#include <WiFi.h>
#include <WebServer.h>
#include <WiFiUdp.h>

// ================== WiFi AP Config ==================
const char *ssid = "ESP_Drone";
const char *password = "12345678";
WebServer server(80);

// ================== iBUS Config ==================
#define IBUS_SERIAL Serial1
#define IBUS_TX_PIN 17
#define CHANNELS 14

uint16_t channels[CHANNELS] = {
  1500,1500,1500,1000,  // AETR: Roll, Pitch, Yaw, Throttle
  1000,1000,1000,1000,  // AUX1–AUX4
  1500,1500,1500,1500,1500,1500
};

// ================== UDP Config ==================
WiFiUDP udp;
const int udpPort = 1234;
char incomingPacket[255];

// ================== AUX States ==================
bool auxState[4] = {false,false,false,false};

// ================== AUX Handling ==================
void setAux(int auxNum, bool state) {
  if(auxNum >=1 && auxNum <=4){
    channels[3 + auxNum] = state ? 1500 : 1000; // CH5–CH8
    auxState[auxNum-1] = state;
    Serial.printf("[AUX] Aux%d set to %s\n", auxNum, state?"ON":"OFF");
  }
}

// ================== Web Page ==================
String buildHTML() {
  String html = "<!DOCTYPE html><html><head><title>ESP Drone Modes</title><style>";
  html += "body{font-family:Arial;text-align:center;background:#1a1a1a;color:white;}";
  html += "h1{margin-top:20px;} .buttons{display:grid;grid-template-columns:repeat(2,150px);grid-gap:20px;justify-content:center;margin-top:50px;}";
  html += ".switch{position:relative;display:inline-block;width:60px;height:34px;} .switch input{display:none;}";
  html += ".slider{position:absolute;cursor:pointer;top:0;left:0;right:0;bottom:0;background:#ccc;transition:.4s;border-radius:34px;}";
  html += ".slider:before{position:absolute;content:'';height:26px;width:26px;left:4px;bottom:4px;background:white;transition:.4s;border-radius:50%;}";
  html += "input:checked + .slider{background:#4CAF50;} input:checked + .slider:before{transform:translateX(26px);} ";
  html += ".status{margin-top:30px;font-size:18px;}</style></head><body>";
  html += "<h1>ESP Drone Modes</h1><div class='buttons'>";

  for(int i=1;i<=4;i++){
    html += "<label class='switch'> <input type='checkbox' id='aux"+String(i)+"' onchange='toggle("+String(i)+")'> <span class='slider'></span></label> Mode "+String(i);
  }

  html += "</div><div class='status' id='status'></div>";

  // JavaScript for instant updates
  html += "<script>";
  html += "function toggle(ch){fetch('/aux?ch='+ch);} ";
  html += "async function update(){let r=await fetch('/status');let j=await r.json();";
  html += "document.getElementById('status').innerHTML=";
  html += "'Throttle: '+j.throttle+'%<br>Roll: '+j.roll+'%<br>Pitch: '+j.pitch+'%<br>Yaw: '+j.yaw;";
  html += "for(let i=1;i<=4;i++){document.getElementById('aux'+i).checked=j['aux'+i];}}";
  html += "setInterval(update,1000); update();";
  html += "</script></body></html>";
  return html;
}

void handleRoot() { server.send(200, "text/html", buildHTML()); }

void handleAux() {
  if(server.hasArg("ch")){
    int ch = server.arg("ch").toInt();
    if(ch>=1 && ch<=4){
      setAux(ch, !auxState[ch-1]); // toggle
    }
    server.send(200,"text/plain","OK");
  } else {
    server.send(400,"text/plain","Bad Request");
  }
}

void handleStatus() {
  String json = "{";
  json += "\"throttle\":" + String((channels[3]-1000)*100/1000) + ",";
  json += "\"roll\":" + String((channels[0]-1000)*100/1000) + ",";
  json += "\"pitch\":" + String((channels[1]-1000)*100/1000) + ",";
  json += "\"yaw\":" + String((channels[2]-1000)*100/1000) + ",";
  for(int i=1;i<=4;i++){
    json += "\"aux"+String(i)+"\":"+(auxState[i-1]?"true":"false");
    if(i<4) json += ",";
  }
  json += "}";
  server.send(200,"application/json",json);
}

// ================== iBUS Packet Send ==================
void sendIBUS() {
  uint8_t packet[32];
  packet[0] = 0x20; // length
  packet[1] = 0x40; // command
  for(int i=0;i<CHANNELS;i++){
    packet[2+i*2] = channels[i]&0xFF;
    packet[2+i*2+1] = (channels[i]>>8)&0xFF;
  }
  uint16_t checksum=0xFFFF;
  for(int i=0;i<30;i++) checksum -= packet[i];
  packet[30]=checksum&0xFF;
  packet[31]=(checksum>>8)&0xFF;
  IBUS_SERIAL.write(packet,32);
}

// ================== Setup ==================
void setup() {
  Serial.begin(115200);
  WiFi.softAP(ssid,password);
  Serial.print("[WiFi AP] IP: "); Serial.println(WiFi.softAPIP());

  server.on("/", handleRoot);
  server.on("/aux", handleAux);
  server.on("/status", handleStatus);
  server.begin();
  Serial.println("[Web] Server started");

  udp.begin(udpPort);
  Serial.print("[UDP] Listening on port "); Serial.println(udpPort);

  IBUS_SERIAL.begin(115200,SERIAL_8N1,-1,IBUS_TX_PIN);
  Serial.println("[iBUS] Output initialized");
}

// ================== Loop ==================
void loop() {
  // if WiFi disconnected → stop output (FC will failsafe)
  if (WiFi.softAPgetStationNum() == 0) {
    delay(50);
    return;
  }

  server.handleClient();

  int packetSize = udp.parsePacket();
  if(packetSize){
    int len = udp.read(incomingPacket,254);
    if(len>0) incomingPacket[len]='\0';

    Serial.print("[UDP] Packet received: "); Serial.println(incomingPacket);

    if(strlen(incomingPacket)>=16){
      char buf[5];
      uint16_t udpChannels[4];
      for(int i=0;i<4;i++){
        strncpy(buf,&incomingPacket[i*4],4);
        buf[4]='\0';
        udpChannels[i]=constrain(atoi(buf),1000,2000);
      }

      channels[0] = udpChannels[2];           // Roll
      channels[1] = 3000 - udpChannels[3];    // Pitch (inverted)
      channels[2] = udpChannels[1];           // Yaw
      channels[3] = udpChannels[0];           // Throttle
    }
  }

  sendIBUS();
  delay(7);
}

Schematic and Layout

afdsasf.jpg

Download Gerbers Download BOM(Bill of materials)

Jan 25,2026

32 views

Micro_Drone

Custom-designed flight controller PCB integrating MCU, IMU, power regulation, and motor outputs for stable multirotor control.

Published: Jan 25,2026

Standard PCB

Download Gerber file 2

BOM(Bill of materials)

Centroid file

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