23 August 2026 · Bharat Raj · originally published on Compoden
Teaching an Arm to See Colour: The Colour Sorting Robot Kit
The Colour Sorting Arm Kit with Arduino Uno + TCS3200 (₹1,200) builds a desktop model of something you've seen in every warehouse video: a machine that looks at an object, decides what it is, and puts it where it belongs. A TCS3200 colour sensor reads red, green or blue objects placed in front of it, and a two-servo arm sweeps each one into its matching bin. Rated Beginner with a 4–5 hour build, it is the most approachable industrial-automation project in our range — sense, decide, act, on your desk, with pre-written and fully commented code. It runs on a 9V supply, includes its own breadboard, and needs no soldering, which is why it turns up in Class 5 science exhibitions and college prototype demos alike.
What's in the box
Arduino Uno R3, TCS3200 colour sensor, two SG90 servos, a 400-point breadboard, 10kΩ resistors, 100nF capacitors, 40 jumper wires (25 male-male, 15 male-female) and a 9V battery snap. The arm hardware mounts as a simple sorting sweep driven by the two servos. Everything is low-voltage and the servo motion is gentle — the product recommends adult supervision only for wire cutting and arm mounting, with the rest child-friendly from about age 10.
What you'll learn
- How colour sensing actually works — the TCS3200 converts light into frequency readings per colour channel, and you'll see raw RGB numbers before they become a "red" decision.
- Servo control with PWM — commanding SG90s to precise angles for repeatable pick-and-sweep motion.
- Conditional logic as a colour map — the heart of the sketch is an honest if/else classifier, the simplest possible version of every sorting system ever built.
- Calibration for the real world — tuning thresholds for your room's lighting so every sort is reliable, which is where the project stops being a demo and becomes engineering.
The build, honestly
Breadboard wiring and arm mounting are straightforward, and the code arrives pre-written and commented in plain English — no programming background needed to get sorting. The step that trips people up is calibration, and it's worth saying plainly: the TCS3200 does not know what "red" is. It reports frequencies that change with ambient light, so the thresholds that worked in the product photos will not be your thresholds. Expect to spend your final hour reading raw values under your actual lighting and adjusting the colour map — the kit treats this as part of the syllabus, and it is genuinely the most valuable hour of the build. Consistent lighting (avoid a window behind the sensor) makes everything easier.
Who it's for — and who should skip it
Built for school science exhibitions, ATL Tinkering Labs, robotics clubs and parents looking for a meaningful STEM weekend — and it scales up: the sensor can distinguish more shades once calibrated, so a three-bin build can grow into a science-fair project with more colours and bins. Early-college students use it to prototype sorting concepts quickly.
Skip it if you want a robot that drives — this one stays on the desk. The Sumo Robot Kit and our Obstacle Avoiding Robot Kit are the moving-robot entries at beginner level. If servo arms are the attraction but you want direct control and more joints, the Gripper Arm Kit gives you a 3DOF arm driven by potentiometer knobs.
FAQ
Is it suitable for a complete beginner with no coding experience?
Yes — the Arduino code is fully pre-written and commented, and the AI companion explains each line. No prior programming knowledge is needed to get the arm sorting.
Can it handle more than three colours?
Yes. Once calibrated, the TCS3200 can differentiate many shades; the learning material shows how to expand the colour map and add bins.
What safety precautions apply for young builders?
Everything runs on low-voltage 9V and the servo arm moves gently. Adult supervision is recommended for wire cutting and mounting; the rest is child-friendly from age 10+.
The kit arrives pre-loaded in Soldr, our AI build assistant, which generates the wiring, the colour-mapping firmware and calibration troubleshooting for this exact sorter.