Room Comfort Controller Kit

Classes 11-12, typical ages 16–18. Age ranges vary by learner. Guided low-voltage electronics.

Activity engagement

120–180 minutes. Explore 20–35 min · Build 40–60 min · Test and discuss 60–85 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. Wi-Fi/BLE experiments also require the local network or phone specified in the guide.

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
• ESP32S 38Pin Development Board (WIFI+BLUETOOTH) — 1 controller board
• MICRO USB DATA CABLE — 1 data cable
• DHT11 — 1 sensor module
• 3.3 V Logic-Level MOSFET Fan Driver Module — 1 driver module
• 1N4007 DIODE (5 PCS) — 1 diode
• Enclosed 5 V Cooling Fan with Safety Grilles — 1 fan
• Enclosed Regulated 5 V Fan Supply with Fitted Lead — 1 power supply
• 10K Ω 1/4 Watts (10 PCS) — 1 resistor
• Bidirectional 3.3 V / 5 V Sensor Data Level Shifter — 1 level-shifter module

What you learn

• A GPIO controls a driver; it does not power a motor.
• Separate on/off thresholds reduce rapid switching.
• Invalid sensor data should lead to a defined fail-safe output.

Connection guide

• DHT11 VCC → USB-powered board 5 V output, GND → GND. DATA has its supplied 10 kOhm pull-up to 5 V.
• Bidirectional data shifter HV → 5 V, LV → 3.3 V, common GND; DHT DATA → HV1, GPIO27 → LV1. Do not connect a 5 V data line directly to ESP32.
• GPIO25 → labelled 3.3 V-compatible driver IN; driver signal GND → ESP32 GND and external supply GND.
• Fan + → separate 5 V supply +; fan − → driver switched OUT−; follow the driver power-terminal labels. Flyback diode across fan: banded cathode to +5 V, anode to fan −.
• Keep the external +5 V separate from the USB-powered ESP32 +5 V. The fan remains inside both safety grilles.

Steps to make it

1. Disconnect all power and identify the supplied part labels and pinouts before wiring.
2. Inspect the enclosed fan, diode orientation and driver labels before enabling power.
3. Upload and record the baseline room temperature. Choose on/off thresholds two degrees apart around the intended test range.
4. Change the sensor temperature gently using hand warmth; observe the fan across both thresholds.
5. With power off, unplug sensor DATA; restart to check the defined fan-OFF error behaviour.
6. Change only the named parameter for the extension, repeat the controlled trials, save observations and disconnect power afterward.

Programming resources

Arduino IDE: install esp32 by Espressif Systems 3.x; select ESP32 Dev Module for the supplied classic WROOM board. Serial Monitor: 115200 baud. GPIO is 3.3 V only.

Libraries to install

• DHT sensor library (Adafruit)
• Adafruit Unified Sensor

Download starter sketch

Test challenge

Log temperature and fan state through a warming/cooling cycle; compare with a single-threshold decision.

Observation task

Time, temperature, on/off thresholds, fan state and invalid-sensor events.

Expected result

Valid temperature above the upper threshold turns the fan on; below the lower threshold turns it off. Invalid data turns it off and reports an error.

If it does not work

Check the external fan supply, common ground, active-high driver input and DHT data level shifter. Never connect a fan directly to a GPIO.

Try next

Add manual override with a timeout and distinguish a classroom control model from a safety-critical controller.

Use and supervision

Use only the supplied enclosed 5 V fan and driver. Keep both grilles fitted, leave the fan unloaded, and disconnect power before wiring. No mains relays, heaters or exposed blades.

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.