What Is a Raspberry Pi?
A Raspberry Pi is a single-board computer (SBC): a whole computer — processor, memory, USB, networking, video output — on one circuit board, running real Linux. Plug in power and a microSD card and it boots like any PC, just smaller, cheaper, and sipping power instead of gulping it.
The original 2012 pitch was "a $35 computer for teaching kids to program." A decade-plus later, the family spans $4 microcontrollers to $150 desktop-class boards, with millions of projects and the best hobbyist documentation of any hardware platform.
The one distinction that matters: Pi vs Pico
The lineup splits into two fundamentally different kinds of device, and mixing them up is the #1 beginner mistake:
Raspberry Pi (5, 4, Zero 2 W...) — a computer. Runs Linux (Raspberry Pi OS). Has gigabytes of RAM, USB, HDMI, Wi-Fi. You SSH into it, install packages, run Python, Docker, servers. If it sounds like a tiny PC, that's because it is.
Raspberry Pi Pico (Pico, Pico W, Pico 2) — a microcontroller. No Linux, no HDMI, kilobytes of RAM. Runs one program, written in MicroPython or C++, talking directly to pins and sensors. It's closer to an Arduino than to a Pi 5 — see the Arduino guide for that mindset.
| Pi (SBC) | Pico (MCU) | |
|---|---|---|
| Runs | Full Linux | One program, no OS |
| RAM | 512MB–16GB | 264–520KB |
| Good at | servers, desktop, AI tinkering | sensors, LEDs, real-time control |
| Power | watts | milliwatts |
| Price | ~$15–150 | ~$4–7 |
Rule of thumb: if the job involves Linux, networking services, or running programs, you want a Pi. If it involves reading a sensor every 100ms on battery power, you want a Pico.
What you actually get
Every full-size Pi (5, 4) gives you:
- 40 GPIO pins — the row of pins along the edge, for buttons, sensors, LEDs, HATs
- USB ports — 2× USB 3.0 + 2× USB 2.0 on Pi 5/4
- Networking — Gigabit Ethernet + Wi-Fi + Bluetooth
- Video — dual micro-HDMI (4K on Pi 5/4)
- Storage — microSD card slot (Pi 5 adds PCIe for NVMe)
What you don't get in the box: a power supply, a case, a microSD card, or cables. Budget for those — a "$60 board" is really a ~$100 project once kitted out. (More on true costs in The Lineup.)
Why people keep buying them
- The software just works. Raspberry Pi OS is Debian with
the rough edges sanded off;
apt installanything. - The community is enormous. Whatever you want to build, someone documented it.
- GPIO on a real computer. Arduino gives you pins without Linux; a PC gives you Linux without pins. The Pi gives you both at once.
- Honest pricing. No subscriptions, no cloud required, no account to run your own hardware.