Traffic Signal Coder Kit

Classes 7-8, typical ages 12–14. Age ranges vary by learner. Guided low-voltage electronics.

Activity engagement

60–90 minutes. Explore 10–15 min · Build 20–30 min · Test and discuss 30–45 min. Estimated time for building, testing and discussion.

What you need

A computer with a USB port and Arduino IDE is required and is not included.

Included components

• Small Breadboard / Mini Solderless Board - 400 points — 1 breadboard
• Jumper Wire Combo - Male to Male, Male to Female and Female to Female Breadboard Connecting Wires (10 Qty Each) — 1 set
• Illustrated Activity Guide and Observation Sheets — 1 set
• Fitted Headers and Labelled Connection Leads — 1 set
• Arduino Uno R3 CH340G version compatible Arduino Development Board — 1 controller board
• USB A to B Programming Cable for Arduino Uno/ Arduino Mega — 1 data cable
• 5mm LED - Red Color — 1 LED
• 5mm LED - Yellow Color — 1 LED
• 5mm LED - Green Color — 1 LED
• 330 Ω 1/4 Watts (10 PCS) — 3 resistor (individual units)

What you learn

• A program can sequence multiple outputs.
• Each LED needs its own resistor.
• Timing changes the behaviour without changing the wiring.

Connection guide

• D8 → 330 Ohm → red LED anode; D9 → 330 Ohm → yellow anode; D10 → 330 Ohm → green anode.
• All three cathodes → GND; no LED is connected directly to a GPIO pin.

Steps to make it

1. Disconnect all power and identify the supplied part labels and pinouts before wiring.
2. Wire the three independently limited LED branches.
3. Open the supplied sketch and predict the output of each stage before uploading.
4. Upload, observe three full cycles, and time each colour.
5. Change the red interval from 3000 ms to 5000 ms, re-upload and compare.
6. Change only the named parameter for the extension, repeat the controlled trials, save observations and disconnect power afterward.

Programming resources

Arduino IDE: select Arduino Uno and the USB port. Use the supplied USB data cable. Serial Monitor/Plotter: 115200 baud.

Uses the selected board core libraries.

Download starter sketch

Test challenge

Does exactly one light stay on at a time, and does the changed interval match the program?

Observation task

Stage, predicted colour, observed colour and measured duration.

Expected result

The LEDs repeat a green → amber → red sequence with programmed durations.

If it does not work

Match D8/D9/D10 to the colour assignments and inspect LED polarity. Uploading requires the selected Uno port.

Try next

Write a timing table for a pedestrian crossing before changing the sketch.

Use and supervision

Use only the supplied low-voltage DC parts. Disconnect power before rewiring; check polarity and labelled pinouts. No soldering or exposed mains connections. Adult guidance is recommended.

How this experiment works

Download class activity guide

Cover illustrations show component types. Functional animations explain principles and are not recorded prototype tests. Follow the supplied connection labels and pinouts.