# 🔌 Microcontroller Comparison: ESP32 vs Arduino Nano vs RP2040

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## 📡 ESP32

**Overview:**  
A powerful and cost-effective microcontroller with **built-in Wi-Fi and Bluetooth** — perfect for IoT and wireless projects.

### ✅ Key Features:
- **Processor:** Dual-core Xtensa @ 240 MHz
- **RAM:** 520 KB internal
- **Flash:** 4 MB (external, typical)
- **Wireless:** Wi-Fi 802.11 b/g/n + Bluetooth 4.2 (classic & BLE)
- **GPIO & Peripherals:** ADC, DAC, PWM, SPI, I2C, UART
- **Special:** Capacitive touch, hall sensor, temperature sensor
- **Power:** Low-power modes for battery operation

**Common Uses:**
- Smart home automation
- Wireless sensor networks
- Web-controlled devices
- Bluetooth-enabled wearables

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## 📏 Arduino Nano

**Overview:**  
A compact, beginner-friendly microcontroller ideal for basic electronics and education.

### ✅ Key Features:
- **Processor:** 8-bit AVR ATmega328P @ 16 MHz
- **RAM:** 2 KB
- **Flash:** 32 KB
- **EEPROM:** 1 KB
- **GPIO:** 14 digital I/O, 6 PWM, 8 analog inputs
- **USB:** Mini-B for programming/power
- **Size:** 45 mm × 18 mm

**Common Uses:**
- Simple embedded systems
- Robotics and automation
- Learning electronics and C/C++ programming

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## 🧠 Raspberry Pi RP2040

**Overview:**  
Raspberry Pi’s first microcontroller — versatile and high-performance, found in the Raspberry Pi Pico.

### ✅ Key Features:
- **Processor:** Dual-core ARM Cortex-M0+ @ 133 MHz
- **RAM:** 264 KB SRAM
- **Flash:** Up to 16 MB external (via QSPI)
- **GPIO & Peripherals:** 26 GPIO, PWM, ADC, I2C, SPI, UART
- **Special:** Programmable I/O (PIO) blocks for custom protocols
- **USB:** USB 1.1 device support
- **Low Cost:** ~$4 for Pico

**Common Uses:**
- Performance-heavy embedded projects
- USB device emulation (keyboards, MIDI)
- Robotics and motor control
- Custom protocols via PIO

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## 🔍 Summary Comparison Table

| Feature             | ESP32                  | Arduino Nano         | Raspberry Pi RP2040       |
|---------------------|-------------------------|-----------------------|----------------------------|
| **CPU**             | Dual-core @ 240 MHz     | 8-bit AVR @ 16 MHz    | Dual-core @ 133 MHz       |
| **Architecture**    | Xtensa LX6              | AVR                   | ARM Cortex-M0+            |
| **RAM**             | 520 KB                  | 2 KB                  | 264 KB                    |
| **Flash**           | 4 MB (external)         | 32 KB                 | Up to 16 MB (external)    |
| **Wireless**        | Wi-Fi + Bluetooth       | None                  | None                      |
| **GPIO/PWM/ADC**    | Yes                     | Yes                   | Yes + PIO                 |
| **USB Support**     | Yes (program/debug)     | Yes (Mini-B)          | Yes (USB device mode)     |
| **Price**           | ~$5–10                  | ~$3–5                 | ~$4 (Pico)                |
| **Best For**        | IoT, wireless control   | Beginners, prototyping| Flexibility, custom I/O   |

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