SMARS is the robot that launched a thousand first builds. If you’ve ever wanted to go from zero to a moving, coding robot without spending a fortune or hunting down special hardware, this is where you start.
What is SMARS?
SMARS stands for Screwless Modular Assemblable Robotic System. It’s a small tracked robot designed to be 3D-printed and held together with snap-fit connections — no screws, no glue, no specialist tools. The original design was created by Kevin McAleer and released as open source, and a whole community has grown around it ever since.
The core robot is compact — around 100mm long — and runs on two DC motors with tank-style tracks. The main board is an Arduino Uno or Nano, making it approachable for beginners. The Pico and Pico W versions (PicoSMARS) bring MicroPython and wireless connectivity into the mix. There are also quad-legged variants, mini versions, and countless community mods.
What’s inside a SMARS
For all its charm, SMARS is a beautifully minimal robot. A board for the brain, a motor driver, two geared motors driving the tracks, and a distance sensor up front — every part snaps into the printed chassis with no screws:
flowchart LR
BATT["Battery"] --> BOARD["Arduino / Pico<br/>(the brain)"]
BOARD --> DRIVER["Motor driver<br/>(H-bridge shield)"]
DRIVER --> ML["Left motor + track"]
DRIVER --> MR["Right motor + track"]
US["Ultrasonic sensor<br/>(front)"] --> BOARD
Two tracks for differential drive, one sensor to avoid walls, all held in a snap-fit printed body — that simplicity is exactly why SMARS is such a brilliant first build.
Why robot builders care
SMARS ticks nearly every box for a first robot:
- Printable — download the STL files, print in PLA, done.
- Modular — swap sensor mounts, add new attachments, or remix the chassis entirely.
- Cheap — the electronics cost around £15–£20 depending on what you have.
- Teachable — the simple two-motor differential drive is a perfect sandbox for learning PID control, obstacle avoidance, line following, and more.
- Community-backed — thousands of builders have shared remixes, and the SMARS Fan site collects the best of them.
Whether you’re using C++ on an Arduino or MicroPython on a Pico W, the hardware stays the same. That means you can focus on learning to code rather than fighting the build.
Get started
The best place to begin is the full SMARS course — it walks you through printing the parts, wiring up the motors, and getting your first code running. Once you’ve got it moving, the Learn to program SMARS with Arduino course takes you step by step through writing proper robot code.
Want to design your own SMARS variant? The Build a SMARS Robot in Fusion 360 course shows you how to model new parts from scratch.
If you want to swap the Arduino for a Raspberry Pi Pico W and write MicroPython, check out the PicoSMARS 2 project — it adds WiFi to the mix and opens up all sorts of remote-control possibilities.
SMARS is proof that you don’t need a big budget or a workshop full of gear to build something genuinely capable. Print the parts, snap it together, and start coding. That first time the tracks spin under your own code is a moment you won’t forget.
Reacts well with
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