FREE SIMULATOR EXAMPLE · INTERMEDIATE

Wi Fi Controlled 4WD Robot Car

This example runs a WiFi-controlled 4WD robot car on the ESP32 — a web page sends direction commands, and the firmware maps them to differential drive. The browser-steered robot pattern.

Board	ESP32 DevKit (Xtensa LX6, 240 MHz)
Difficulty	intermediate
Category	robotics
Libraries	None — just the Arduino core
Runs in	Sensbench browser simulator — free, no account

The exact circuit you get when you open this example — already wired, ready to run.

The sketch

# main.py
import network
import socket
from machine import Pin
import time

# Wi-Fi credentials
SSID = "kritish"
PASSWORD = "pass"
# Driver 1 (Front)
IN1 = Pin(27, Pin.OUT)
IN2 = Pin(26, Pin.OUT)
IN3 = Pin(25, Pin.OUT)
IN4 = Pin(33, Pin.OUT)

# Driver 2 (Rear)
IN5 = Pin(19, Pin.OUT)
IN6 = Pin(18, Pin.OUT)
IN7 = Pin(5, Pin.OUT)
IN8 = Pin(17, Pin.OUT)

def forward():
    IN1.value(1); IN2.value(0)
    IN3.value(0); IN4.value(1)
    IN5.value(1); IN6.value(0)
    IN7.value(0); IN8.value(1)

def backward():
    IN1.value(0); IN2.value(1)
    IN3.value(1); IN4.value(0)
    IN5.value(0); IN6.value(1)
    IN7.value(1); IN8.value(0)

def left():
    IN1.value(1); IN2.value(0)  
    IN3.value(1); IN4.value(0)  
    IN5.value(1); IN6.value(0)  
    IN7.value(1); IN8.value(0)  

def right():
    IN1.value(0); IN2.value(1)  
    IN3.value(0); IN4.value(1)  
    IN5.value(0); IN6.value(1)  
    IN7.value(0); IN8.value(1)  

def stop():
    IN1.value(0); IN2.value(0)
    IN3.value(0); IN4.value(0)
    IN5.value(0); IN6.value(0)
    IN7.value(0); IN8.value(0)

# Wi-Fi Connect
wifi = network.WLAN(network.STA_IF)
wifi.active(True)
wifi.connect(SSID, PASSWORD)

print("Connecting to Wi-Fi...")
while not wifi.isconnected():
    time.sleep(0.5)
    print(".")

print("Connected! IP:", wifi.ifconfig()[0])

# Web Page
def webpage():
    html = """<!DOCTYPE html>
<html>
<head>
    <title>ESP32 Car</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <style>
        body { text-align: center; font-family: Arial; background: #1a1a2e; color: white; }
        h1 { color: #e94560; }
        .btn {
            display: inline-block;
            padding: 20px 30px;
            margin: 10px;
            font-size: 24px;
            background: #16213e;
            color: white;
            border: 2px solid #e94560;
            border-radius: 10px;
            cursor: pointer;
            text-decoration: none;
        }
        .btn:hover { background: #e94560; }
        .row { margin: 10px; }
    </style>
</head>
<body>
    <h1>ESP32 Car Control</h1>
    <div class="row">
        <a class="btn" href="/forward">Forward</a>
    </div>
    <div class="row">
        <a class="btn" href="/left">Left</a>
        <a class="btn" href="/stop">Stop</a>
        <a class="btn" href="/right">Right</a>
    </div>
    <div class="row">
        <a class="btn" href="/backward">Backward</a>
    </div>
</body>
</html>"""
    return html

# Web Server
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(('', 80))
server.listen(5)
print("Server started!")

while True:
    conn, addr = server.accept()
    request = conn.recv(1024).decode()
    
    if '/forward' in request:
        forward()
    elif '/backward' in request:
        backward()
    elif '/left' in request:
        left()
    elif '/right' in request:
        right()
    elif '/stop' in request:
        stop()
    
    conn.send('HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\n')
    conn.send(webpage())
    conn.close()

How it works

The firmware serves a web control page and translates the incoming direction commands into motor driver signals. The differential drive math is the core: turning left means the left motors reverse or slow while the right motors drive forward — speed differences steer the chassis.

The motor drivers take direction and speed per channel, and the firmware maps the four commands onto them. The serial output logs each command, so the mapping from web input to motor behavior is traceable.

Before you build it for real

Get the parts

Related examples

FAQ

Why four-wheel drive?

4WD shares the load across four motors — better traction and redundancy for a small robot chassis. The control side is identical to 2WD: each motor pair gets a driver channel, and the firmware’s job is turning direction commands into motor signals.

How does WiFi control the car?

The ESP32 serves a control page: buttons or a joystick widget send direction commands over HTTP, and the firmware maps them to the motor drivers. Forward, back, left and right become the classic differential-drive outputs.