ESP32 vs Arduino vs Raspberry Pi: what’s the real difference, and which one should you buy?

If you’re new to DIY electronics, it’s easy to think ESP32, Arduino, and Raspberry Pi are three versions of the same thing.

They’re not.

A lot of “ESP32 vs Arduino vs Raspberry Pi” confusion comes from comparing them like they’re all meant to do the same job. The real split is simpler:

• ESP32 and Arduino are usually microcontrollers: they run one program, talk to sensors and pins, and can be very power efficient.
• Raspberry Pi is a single-board computer: it runs Linux, can run lots of programs at once, and behaves more like a small PC.

To keep this practical, here are three boards people commonly compare:

• ESP32-S3 DevKit (ESP32 family)
• Arduino UNO R4 WiFi (Arduino family)
• Raspberry Pi 5 (Raspberry Pi family)

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TL;DR

If your project is “a device” (sensors, relays, lights, quick response, battery), start with a microcontroller like an ESP32-S3 or an Arduino UNO R4 WiFi. If your project is “a system” (Home Assistant, Docker, dashboards, databases, multiple services running 24/7), you’ll usually be happier with a Raspberry Pi 5. The UNO R4 WiFi is a nice bridge for beginners because it keeps the Arduino workflow, but it also includes an ESP32-S3 module for Wi-Fi and Bluetooth.

Quick comparison table

The key concept: microcontroller vs computer

Microcontroller (ESP32, Arduino)

A microcontroller is designed to run a single program (firmware) that:

• starts quickly and runs reliably
• reads sensors and controls pins (GPIO)
• does one job very well
• can save power using low-power modes

If you want a device that wakes up, reads something, sends it, and goes back to sleep, microcontrollers are built for that. ESP32-S3, for example, is described as a low-power SoC that supports 2.4 GHz Wi-Fi and Bluetooth LE.

Single-board computer (Raspberry Pi)

A Raspberry Pi is designed to run Linux and behave like a small computer:

• multiple programs can run at once
• you can install software packages and services
• it can host dashboards, databases, and automations
• it’s great as an always-on hub

Raspberry Pi 5’s product brief lists a quad-core Cortex-A76 at 2.4GHz and explicitly frames it as a full-size computer platform with modern I/O.

A quick rule of thumb:

• If it sounds like “a gadget” you build and forget, that’s usually a microcontroller.
• If it sounds like “a box that runs software”, that’s usually a Raspberry Pi.

ESP32-S3 DevKit

What it is

ESP32-S3 is a Wi-Fi and Bluetooth LE capable microcontroller. Espressif’s datasheet describes it as a dual-core Xtensa LX7 based SoC with 2.4 GHz Wi-Fi and Bluetooth LE.

You’ll often see the CPU speed mentioned (up to 240 MHz). That’s real, but it’s best treated as a rough indicator, not a “this is X times better” comparison. Different chips can have very different performance per MHz. The more useful takeaway is: it has enough headroom to handle networking, encryption, and typical IoT workloads comfortably for a microcontroller.

What it’s best for

ESP32-S3 is a strong choice when you care about any of these:

• Wi-Fi devices (sensors, relays, meters)
• Bluetooth LE projects
• smart home nodes that talk to your network
• low power designs that use sleep modes

The datasheet also highlights multiple low-power modes and a low-power coprocessor, which is exactly the kind of feature set that makes sense for battery devices.

What to know before buying

“ESP32-S3 DevKit” isn’t one single board. Different sellers ship different versions with different memory and layouts. If you’re planning to run heavier features like a web dashboard or encrypted connections, it’s worth checking the exact specs in the listing (flash size and whether it includes PSRAM) before you buy.

Arduino UNO R4 WiFi

What it is (and the “does it include an ESP32?” question)

Yes. The UNO R4 WiFi has:

• a Renesas RA4M1 microcontroller as the main CPU you use for typical Arduino sketches
• an ESP32-S3 module used for Wi-Fi and Bluetooth connectivity

Arduino’s datasheet spells out the basics: RA4M1 is a 48 MHz Arm Cortex-M4, with 256 kB flash and 32 kB SRAM, and the board includes an ESP32-S3 module for wireless plus a built-in 12×8 LED matrix.

A simple way to think about it:

• The UNO R4 WiFi is an Arduino-style microcontroller board first.
• The ESP32-S3 is a built-in wireless helper, and it can also be accessed separately.

Why beginners often like it

If you want the classic Arduino learning path, UNO boards are still one of the simplest on-ramps:

• plenty of tutorials
• predictable “write sketch, upload, it runs” workflow
• lots of compatible accessories and shields

The UNO R4 WiFi keeps that feel, but it’s also a modern 32-bit UNO.

The one gotcha to understand (voltages)

The UNO R4 WiFi is a bit unusual because it has two “worlds” on the same board:

• The main UNO side is 5V
• The onboard ESP32-S3 wireless module is 3.3V

That matters because mixing 5V signals into 3.3V pins can damage hardware. Arduino specifically warns that the ESP32-S3 pins are not 5V tolerant, so you should not directly connect the 5V UNO-side pins to the ESP32-S3 pins.

If you are only using the board like a normal UNO (sensors, shields, typical Arduino libraries), you can ignore this most of the time. It mainly matters if you start using the ESP32-S3 side directly or wiring signals between the two sides.

Raspberry Pi 5

What it is

Raspberry Pi 5 is a Linux-capable single-board computer. In the official product brief, Raspberry Pi 5 is specified as:

• Broadcom BCM2712 quad-core 64-bit Arm Cortex-A76 at 2.4GHz
• dual-band 802.11ac Wi-Fi
• Bluetooth 5.0 / BLE
• PCIe 2.0 x1 interface
• 5V/5A power via USB-C with Power Delivery support

That set of features is the giveaway: this is a board meant to act like a computer, not like a small sensor node.

What it’s best for

Raspberry Pi 5 makes sense when the project sounds like any of the following:

• “I want to run Home Assistant”
• “I want to run Docker containers”
• “I want a dashboard, database, and automations running all the time”
• “I want a small server to host services”

It’s also a good choice when you want a lot of I/O and bandwidth options compared to typical microcontrollers.

The tradeoffs (for beginners)

A Pi is flexible, but it comes with “computer responsibilities”:

• stable power matters (the product brief calls out 5V/5A over USB-C with PD)
• storage quality matters
• you’ll deal with updates and OS maintenance

None of that is “bad”, it’s just not the same experience as a microcontroller.

How to choose

Choose ESP32-S3 DevKit if

• wireless is core to your project (Wi-Fi or BLE)
• you want a dedicated device that does one job
• you care about low power options (sleep modes)

Choose Arduino UNO R4 WiFi if

• you want the classic Arduino learning curve
• you like the UNO ecosystem and accessories
• you want Wi-Fi/Bluetooth available, but you still want the Arduino-style workflow

Choose Raspberry Pi 5 if

• you want Linux and real software installs
• you want multiple services running at once (Home Assistant, MQTT, Zigbee2MQTT, dashboards)
• your project is more “home server” than “sensor node”

A quick decision checklist

If you say “yes” to any of these, Raspberry Pi is usually the right category:

• Do I need Linux apps or Docker?
• Do I want to run multiple services at the same time?
• Do I need local storage, databases, or logs?

If you say “yes” to any of these, a microcontroller is usually the right category:

• Do I need to read sensors or control GPIO reliably?
• Do I want quick startup and simple behaviour?
• Do I want battery-friendly power options?

Common misconceptions

“A Raspberry Pi can replace an Arduino”

Sometimes, but it’s often the wrong direction. Pis are great as a hub. Microcontrollers are great as the endpoints (sensors, relays, buttons).

“ESP32 is just an Arduino with Wi-Fi”

ESP32 can be programmed using Arduino-style tools, but it’s an IoT-first platform with built-in wireless and a bigger feature set.

“UNO R4 WiFi is basically an ESP32”

It includes an ESP32-S3 module, but the main Arduino brain is the RA4M1. Think “Arduino board with built-in wireless”, not “ESP32 board in disguise”.

What to buy

If you just want a simple shopping list (and you do not want to overthink it), here are three bundles depending on what you’re trying to build.

If you want a Wi-Fi smart home sensor node

• ESP32-S3 DevKit
• Breadboard + jumper wire kit
• Basic sensor kit (temperature/humidity, light sensor, motion sensor)

This is the “small connected device” path. It’s ideal when you want a sensor or controller that talks to your network.

If you want the easiest learning curve

• Arduino UNO R4 WiFi
• UNO-compatible beginner electronics kit (breadboard, wires, resistors, LEDs, basic sensors)

This is the most beginner-friendly route if you want to learn the basics first and still have wireless available on the board.

If you want a Home Assistant or “always-on” home server

• Raspberry Pi 5
• Reliable USB-C Power Delivery power supply (Pi 5 expects 5 V / 5 A over USB-C with PD support)
• Case + cooling
• Storage you trust (start with a good microSD card, or a more robust option if you already know you’ll log a lot of data)

This is the “runs software and services 24/7” path. It’s the right pick when you want Linux and multiple things running at once.

Final takeaway

Most of the time, this isn’t a three-way fight. It’s a “what kind of computer do I actually need?” decision.

• If you’re building a device that reads sensors, controls relays, switches lights, or needs to run on low power, start with a microcontroller: ESP32-S3 or Arduino UNO R4 WiFi.
• If you’re building a box that runs software (Home Assistant, Docker, dashboards, databases, multiple services), start with a Raspberry Pi 5.

Once you pick the right category, choosing the exact board gets way easier.