Brain Bots

30 minmedium

MISSION 17 · INTERMEDIATE ARDUINO

Two-Clue Light

Make two-clue light. Explore and and or.

Public beta missionThese revised instructions are open for learning while actual-kit testing is pending. A grown-up must confirm every setup check before power is connected. If a rating, pin card or required check is missing, explore the idea on screen and leave the physical build unpowered.

2 · Light Explorers

Your new skill: AND and OR

Revisit the skill you will reuse: two eye light compass

WHAT YOU'LL USE

Match these to your kit

Arduino UnoUSB A-to-B data cableHalf-size breadboardMale–male / male–female jumper wires (as needed for actual module terminals)1 LDR, 1 × 2.7 kΩ, 1 button, 1 LED, 1 × 2.2 kΩ

Gather from home

Computer with Arduino IDE and Serial Monitor

Reuse the parts between missions; these are not 45 simultaneous installations. Red/yellow/green means those three monochrome colours. RGB is a separate component with three channels.

BEFORE YOU BUILD

Unplug USB before changing connections. Use only the USB supply for this build; never connect 9V to 5V or a signal pin, and never connect to mains. An adult verifies variant, printed pin labels and resistor values before powering. Stop and unplug if a part becomes hot or damaged.

YOUR REWARD

+30 XPMission completion

PREDICT BEFORE YOU BEGIN

Before the test: which input will change, and what signal or reading do you expect?

BEFORE YOU BUILD

Parent check: exact part variant, labelled pins and stated values. If a check cannot be confirmed, keep this physical build unpowered and explore the code and prediction instead.

YOUR CHALLENGE

Build two-clue light and prove its rule.

NEW POWER-UP

AND and OR

You have explored compare two calibrated inputs. Now try and and or.

Adult help: Adult helps with computer setup, first wiring and any water/cutting. Learner predicts, tests and explains.

See the idea before you build

How a breadboard connects inside

Each coloured strip is one connected group. Different numbered rows stay separate. This explains the board; use the mission’s exact connection reference for component positions. Check rail breaks on your supplied board.

ldr divider learning diagram — See the idea, then follow this mission’s exact pin-to-pin map below. · Tap to enlarge

Exact labelled connections for Two-Clue Light — Pin-to-pin reference for this sketch. Match printed labels and actual component variant. · Tap to enlarge

Open the complete Arduino code

Copy the complete code into Arduino IDE or download the sketch. Follow the matching component card before connecting power.

// First Wonder Brain Bots 17 — Two-Clue Light
// USB-powered model. Unplug before rewiring. Serial Monitor: 9600 baud.
int threshold=500;
bool useAnd=true;
const byte buttonPins[]={2};const byte buttonCount=1;

void setup(){Serial.begin(9600);pinMode(8,OUTPUT);digitalWrite(8,LOW);pinMode(2,INPUT_PULLUP);Serial.println("Ready. Follow your mission test.");}
void loop(){
  unsigned long now=millis();
  
bool dark=analogRead(A0)<threshold,pressed=digitalRead(2)==LOW;digitalWrite(8,useAnd?(dark&&pressed):(dark||pressed));
}

Check the connection map

CONNECTION MAP

Build the electrical path before you test.

Keep power disconnected while changing connections.

JoinConnectWhy it matters

PowerSupplied USB data cable → Uno USB socket; computer at other endThe same cable uploads and supplies this model. Unplug before wiring.

Shared referenceUno GND → breadboard ground railAll module GND terminals use this same reference. Check whether your rail is split.

LED cue 1D8 → 2.2 kΩ → LED anode (+); cathode (−) → GNDUse separate breadboard strips. Short leg/flat rim usually marks cathode; verify.

Button 1D2 → one switched terminal; opposite switched terminal → GNDINPUT_PULLUP: press reads LOW. Four-leg buttons have internally joined pairs; use a verified switched pair.

LDR 15V → LDR → junction → 2.7 kΩ → GND; junction → A0This divider normally reads higher in brighter light. Calibrate the actual part.

Kit variant and values confirmed by an adult

All pins match the map; USB was disconnected while wiring

Test includes expected, non-triggering and recovery cases

BUILD PATH

STEP 1 OF 6

Meet your mission

Try · Notice · ExplainRead the checkpoint, make a prediction, then test your idea.

You will explore and and or. Gather the kit and home materials below. Unplug USB. Match the part names and printed labels.

Watch this step

A video demonstration will appear here when it is ready. You can follow the written step now.

Read the video instructions

You will explore and and or. Gather the kit and home materials below. Unplug USB. Match the part names and printed labels.

Need a diagram for this step?

WHAT'S REALLY HAPPENING?

Why it works

AND and OR. Raw light readings depend on this divider and your room. They are not calibrated lux. Check your rule against an example where it should respond and one where it should not. Only when both required conditions are true.

This is a tabletop learning model. Controllers reuse inputs, decisions and outputs to automate a useful signal.

FAIR-TEST CHALLENGE

Change one input or setting at a time; keep the wiring and protection unchanged. Repeat three trials.

WHEN IT DOESN'T WORK YET

Debug one clue at a time.

Upload or port missing

Likely cause: Wrong board, port or cable connection

Try this first: Check Arduino Uno selection and supplied data cable. Unplug external wiring before checking upload on built-in LED.

Signal does not match the test

Likely cause: Pin labels, input calibration or variant differs

Try this first: Unplug. Compare every connection with the map. Return to the earlier single-input mission; test one subsystem at a time.

Reading is unknown or unstable

Likely cause: Sensor settling, target, contact or calibration

Try this first: Follow the exact test setup; allow settling, use a flat target or check module pinout unpowered. Never replace unknown with a guessed safe reading.

CLEAN, RESET AND STORE

Disconnect USB, remove wires carefully and store components dry.

NEXT SKILL

Arm, latch and acknowledge