Bluetooth LED Control Kit

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

Activity engagement

90–150 minutes. Explore 15–30 min · Build 30–50 min · Test and discuss 45–70 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
• 5mm LED - Red Color — 1 LED
• 330 Ω 1/4 Watts (10 PCS) — 1 resistor
• Tactile Push Button Switch 12x12x8mm 4-Pin — 1 button

What you learn

• BLE exposes data through services and characteristics.
• Received commands should be checked before changing an output.
• A classroom LED control service is not an authenticated lock or appliance controller.

Connection guide

• GPIO25 → 330 Ohm → LED anode; cathode → GND.
• Local clear button → GPIO26 and GND, using INPUT_PULLUP.

Steps to make it

1. Disconnect all power and identify the supplied part labels and pinouts before wiring.
2. Wire the LED and button and upload using the ESP32 core BLE library.
3. Use a BLE GATT browser app on a compatible phone; connect to TechyTron LED Lab.
4. Write UTF-8 text 1 or 0 to the characteristic shown in the guide; compare valid and invalid commands.
5. Press the local clear button and verify it switches the LED off without a phone.
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.

Uses the selected board core libraries.

Download starter sketch

Test challenge

Test 1, 0 and an unrelated character; reconnect and repeat.

Observation task

Command bytes, expected LED state, observed state and connection status.

Expected result

Only a leading 1 or 0 changes the LED state; the button clears it locally. No phone is included.

If it does not work

Use a BLE-capable app, select write-as-text rather than a decimal byte, and verify the correct service/characteristic.

Try next

Add notifications for confirmed state changes and discuss pairing/authentication.

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.