MISSION 31 · INTERMEDIATE ARDUINO
Make room reporter. Explore digital sensor and valid-data check.
4 · Room Detectives
Your new skill: Digital sensor and valid-data check
Revisit the skill you will reuse: night watcher model
Match the names to your parts before you build. New parts appear when you first need them. You can point, say the name or show a grown-up.
Reports approximate temperature and relative humidity as digital data.
Look for: Identify bare four-pin sensor or labelled module.
Before using it: Adult verifies pinout and pull-up; read at least two seconds apart.
Your turn: Name the units: degrees Celsius and relative-humidity percent.
WHAT YOU'LL USE
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. Confirm bare sensor versus module before wiring. No flame, steam, direct heat or breath tests.
YOUR REWARD
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
NEW POWER-UP
Digital sensor and valid-data check
You have explored combine tested sensor subsystems. Now try digital sensor and valid-data check.
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.
Copy the complete code into Arduino IDE or download the sketch. Follow the matching component card before connecting power.
// First Wonder Brain Bots 31 — Room Reporter
// USB-powered model. Unplug before rewiring. Serial Monitor: 9600 baud.
#include <DHT.h>
DHT climate(11,DHT11);bool climateValid=false;float temperature=0,humidity=0;unsigned long lastClimate=0;
bool sampleClimate(unsigned long now){if(now-lastClimate<2000)return false;lastClimate=now;
float t=climate.readTemperature(),h=climate.readHumidity();climateValid=!isnan(t)&&!isnan(h);
if(climateValid){temperature=t;humidity=h;}return true;}
void printClimate(){if(!climateValid){Serial.println("CLIMATE UNKNOWN");return;}
Serial.print("T C: ");Serial.print(temperature);Serial.print(" RH percent: ");Serial.println(humidity);}
void setup(){Serial.begin(9600);climate.begin();Serial.println("Ready. Follow your mission test.");}
void loop(){
unsigned long now=millis();
if(sampleClimate(now)){printClimate();}
}
CONNECTION MAP
BUILD PATH
STEP 1 OF 6
You will explore digital sensor and valid-data check. Gather the kit and home materials below. Unplug USB. Match the part names and printed labels.
A video demonstration will appear here when it is ready. You can follow the written step now.
You will explore digital sensor and valid-data check. Gather the kit and home materials below. Unplug USB. Match the part names and printed labels.
WHAT'S REALLY HAPPENING?
Digital sensor and valid-data check. DHT11 provides approximate readings; invalid values must not become confident advice. Check your rule against an example where it should respond and one where it should not. Show UNKNOWN rather than a made-up measurement.
This is a tabletop learning model. Real systems also need reliable power, robust sensors and careful handling of unknown measurements; this kit model is not a safety or security device.
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
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.
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.
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
Classify valid humidity