Beginner6-day build

Line-Following Rover

Your first taste of autonomy: a robot that drives itself.

A six-day build of a rover that follows a line on the floor entirely on its own. You'll design a compact base and a parametric sensor mount in Onshape, wire up a reflectance sensor array, and write a real closed-loop controller. The single best introduction to how autonomous robots actually think.

day streak

Mechanical Design & CADElectronics & WiringFirmware & Code

U-ChannelFlat BracketsMotor Hubs12V GearmotorsCaster WheelReflectance Sensor Array

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Understand closed-loop control
A line follower is your first 'closed-loop' robot: it senses the world (where's the line?), decides (am I drifting left or right?), and acts (steer back). It repeats this dozens of times a second. Every self-driving behavior, from a Roomba to a Tesla, is this same loop scaled up. Grasping it here unlocks all of robotics.
Plan a small, low robot
Line followers work best small, light, and low to the ground, with the sensor out front leading the wheels. Sketch a two-driven-wheel rover with a single caster at the back for balance — a 'differential drive.' Decide roughly how big it is and where the sensor bar will hang. Keep the center of mass low and between the wheels so it doesn't tip when it turns hard.
Set up Onshape and the parts library
If you haven't already, make an Onshape account and import the ProtoHouse part library. If you built the Tank Bot, you'll reuse the same channels, motors, hubs, and the 16mm grid — this build is a step up in brains, not in CAD difficulty.

Line-Following Rover

Day 1 — Plan and understand the idea

Understand closed-loop control

Plan a small, low robot

Set up Onshape and the parts library

Day 2 — Design the rover base

Day 3 — Design a parametric sensor mount

Day 4 — Electronics and wiring

Day 5 — Read the line in code

Day 6 — Close the loop and tune