Which is better for beginners: ESP32 or STM32? A robot example

For beginners in embedded systems, the ESP32 is generally more suitable than the STM32 for several reasons:

1. Easier Development Environment

• ESP32:

  • Works well with the Arduino IDE, which is beginner-friendly.

  • Supports MicroPython, allowing beginners to write code in Python instead of C/C++.

  • PlatformIO (VS Code extension) simplifies project management.

• STM32:

  • Typically requires STM32CubeIDE or Keil/IAR (which have a steeper learning curve).

  • More complex setup for beginners (register configurations, HAL/LL libraries).

2. Built-in Wireless Connectivity

• ESP32 has Wi-Fi & Bluetooth built-in, making it great for IoT projects.

• STM32 usually requires external modules (like ESP8266 or HC-05 for Bluetooth), adding complexity.

3. Better Community & Documentation

• ESP32 has a larger hobbyist community, with many tutorials (YouTube, blogs, forums).

• STM32 is more industry-focused, with documentation that can be overwhelming for beginners.

4. Lower Cost & Easier Availability

• ESP32 boards (like ESP32 DevKit) are cheaper (~$5–$10) and widely available.

• STM32 boards (like STM32F103 "Blue Pill") are also affordable but may require extra components.

When Should a Beginner Choose STM32?

• If you want to learn professional embedded development (real-time systems, automotive, industrial applications).

• If you need better real-time performance or low-power applications (STM32 has better power management).

• If you plan to work in an industry that uses STM32 heavily.

Conclusion

• For beginners (IoT, easy prototyping, simple projects) → ESP32 ✅

• For deeper embedded learning (RTOS, registers, industry standards) → STM32

Let’s compare ESP32 vs. STM32 for building a robot (e.g., a WiFi/Bluetooth-controlled car with sensors). We’ll break it down by key robot components and declare a winner for each.

1. Motor Control (DC/BLDC Motors)

ESP32 (Arduino + PWM)

// L298N Motor Driver Example (2 DC motors)  
#define ENA 14  // PWM for Motor A  
#define IN1 12  // Direction pins  
#define IN2 13  

void setup() {  
  pinMode(ENA, OUTPUT);  
  pinMode(IN1, OUTPUT);  
  pinMode(IN2, OUTPUT);  
  ledcSetup(0, 5000, 8);  // PWM Channel 0, 5kHz, 8-bit  
  ledcAttachPin(ENA, 0);  
}  

void loop() {  
  digitalWrite(IN1, HIGH);  // Forward  
  digitalWrite(IN2, LOW);  
  ledcWrite(0, 200);  // ~78% duty cycle  
}  

✅ Pros:

• Simple PWM control (ledc library).

• Good for basic robots (e.g., line followers).

❌ Cons:

• Limited precision for high-speed BLDC control (no hardware dead-time insertion).

STM32 (Hardware PWM + TIMERS)

// STM32CubeMX configures TIM1 for PWM  
HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_1);  // Motor A  
htim1.Instance->CCR1 = 500;  // Set duty cycle  

// Direction control via GPIO  
HAL_GPIO_WritePin(GPIOC, GPIO_PIN_0, GPIO_PIN_SET);  // Forward  

✅ Pros:

• Hardware timer support for advanced motor control (e.g., field-oriented control for BLDC).

• Better for robots needing precision (drones, robotic arms).

Winner:

• STM32 for advanced motor control.

• ESP32 for simple wheeled robots.

2. Wireless Control (WiFi/Bluetooth)

ESP32 (Built-in WiFi/BLE)

// WiFi Remote Control (Web Server)  
#include <WiFi.h>  
WiFiServer server(80);  

void setup() {  
  WiFi.begin("SSID", "PASSWORD");  
  server.begin();  
}  

void loop() {  
  WiFiClient client = server.available();  
  if (client) {  
    String cmd = client.readString();  
    if (cmd == "FWD") moveForward();  // Custom function  
  }  
}  

✅ Pros:

• No extra modules needed.

• Supports MQTT/WebSocket for IoT robots.

STM32 (External Modules Required)

// Using HC-05 Bluetooth (UART AT Commands)  
HAL_UART_Transmit(&huart2, "AT+CONNECT=ESP32\r\n", ...);  

❌ Cons:

• Needs extra hardware (HC-05, ESP8266 for WiFi).

• More complex firmware (parsing AT commands).

Winner:

• ESP32 (clear winner for wireless robots).

3. Sensor Integration (Ultrasonic, IMU, LiDAR)

ESP32 (Arduino Libraries)

// HC-SR04 Ultrasonic Sensor  
#define TRIG 25  
#define ECHO 26  

void setup() {  
  pinMode(TRIG, OUTPUT);  
  pinMode(ECHO, INPUT);  
}  

float readDistance() {  
  digitalWrite(TRIG, HIGH);  
  delayMicroseconds(10);  
  digitalWrite(TRIG, LOW);  
  return pulseIn(ECHO, HIGH) * 0.034 / 2;  // cm  
}  

✅ Pros:

• Plug-and-play with Arduino libraries (e.g., MPU6050, VL53L0X).

STM32 (HAL Libraries + Manual Config)

// STM32 HAL Ultrasonic (TIM + GPIO)  
HAL_GPIO_WritePin(TRIG_PORT, TRIG_PIN, GPIO_PIN_SET);  
delay_us(10);  
HAL_GPIO_WritePin(TRIG_PORT, TRIG_PIN, GPIO_PIN_RESET);  
uint32_t pulse = HAL_GPIO_ReadPin(ECHO_PORT, ECHO_PIN);  

✅ Pros:

• Lower latency (better for high-speed sensors like LiDAR).

Winner:

• ESP32 for simplicity.

• STM32 for high-performance sensors (e.g., Kalman filtering on IMU).

4. Real-Time Performance (RTOS, Latency)

ESP32 (FreeRTOS Pre-Installed)

// Task for motor control  
void motorTask(void *pvParam) {  
  while (1) {  
    updateMotors();  
    vTaskDelay(10 / portTICK_PERIOD_MS);  
  }  
}  

✅ Pros:

• Decent for most robots (e.g., obstacle avoiders).

STM32 (Hard Real-Time)

// STM32 + FreeRTOS (CubeMX configured)  
void StartMotorTask(void *arg) {  
  while (1) {  
    HAL_GPIO_TogglePin(MOTOR_PIN);  
    osDelay(1);  // 1ms precise delay  
  }  
}  

✅ Pros:

• Predictable timing (critical for balancing robots/drones).

Winner:

• STM32 for real-time-critical robots (e.g., quadcopters).

5. Power Efficiency (Battery-Powered Robots)

• ESP32:

  • Higher idle power (~10mA in deep sleep).

  • Wi-Fi/BLE drain battery faster.

• STM32:

  • As low as 2µA in standby (better for long-duration robots).

Winner:

• STM32 for battery efficiency.

Final Robot Build Recommendations

Example Projects:

1. ESP32 Robot Car (WiFi Control + Ultrasonic Avoidance):

   • Motors: L298N + ESP32 PWM.

   • Wireless: Built-in WiFi for phone control.

   • Sensors: HC-SR04, MPU6050 (Arduino libraries).

2. STM32 Robotic Arm (Precision Control):

   • Motors: STM32 TIM1 PWM + PID.

   • Wireless: Optional (HC-05 for BLE).

   • Sensors: Rotary encoders + STM32 HAL.

For Beginners: Start with an ESP32 robot (easier to debug).
For Advanced Users: STM32 for drones/industrial robots.