The one-sentence version
Arduino is a microcontroller — it runs one program, directly on the chip, with no operating system to fight with. Raspberry Pi is a full computer that happens to have GPIO pins bolted on. That difference decides almost everything else.
| Arduino | Raspberry Pi | |
|---|---|---|
| What it is | Microcontroller | Full single-board computer |
| Boots in | Instantly | 20–40 seconds, like a PC |
| Runs when powered off unexpectedly | Fine — nothing to corrupt | Risk of SD card corruption if not shut down cleanly |
| Real-time timing (exact microsecond control) | Excellent | Poor — an OS is multitasking underneath you |
| Networking, cameras, displays, USB devices | Limited / needs extra hardware | Native support |
| Logic level | 5V tolerant (Uno/Nano) | 3.3V only |
| Typical language | C/C++ (Arduino IDE) | Python, or anything really |
Start with Arduino if...
- You're building something with a motor, sensor, or timing-sensitive circuit that needs to run reliably 24/7 without "an OS decided to do a background update" being a possibility.
- You want to just cut power without worrying about corrupting anything.
- Your project is genuinely simple — read a sensor, react, repeat. You don't need a screen, a network connection, or a camera.
Start with Raspberry Pi if...
- Your project involves a camera, a display, a web interface, or talking to the internet.
- You already know (or want to learn) Python, and would rather write in a full language with proper libraries than the more limited Arduino C++ environment.
- You want to run multiple things at once — a sensor logger and a web dashboard, say.
What to actually buy
For a Pi, a Raspberry Pi 4 or 5 starter kit that includes a case, power supply, and a pre-loaded SD card saves a lot of first-week frustration. For Arduino, an Arduino Uno starter kit with a breadboard and a basic component pack (resistors, LEDs, a handful of sensors) is the standard, well-trodden entry point.
Once you've picked one
Going the Arduino route? Start with the first LED project. Going Pi? Read the SD card guide before you leave one running unattended — it's the most common way a Pi project dies.
If you go the Raspberry Pi route, plan your wiring with PinTinker before you start — it'll save you a re-wire once you add your second or third sensor.