Wire a GP2Y1010AU0F dust sensor and SCD30 CO2 sensor to an ESP32 with an OLED display – one sketch, honest trend readings for the jerebu season, and why it can never replace the official API.

Read an RFID card’s UID with the RC522, match it against your allowed list, and switch a 12V lock through a relay module – plus the honest truth about how secure it really is.

Build a DHT11 temperature and humidity monitor with a 0.96-inch OLED on an ESP32 – full wiring table, one runnable sketch, and no extra resistors needed.

Ten RBT electronics project ideas for Form 1-3, sorted by difficulty – from a no-code solar fan to a line follower robot – with the parts list and links to free step-by-step guides.

Build a working Arduino traffic light with three LEDs, 220 ohm resistors and a mini breadboard – complete wiring tables, full code and the mistakes we see real customers make.

A stable 5V into micro-USB or VIN — from a good adapter, or from a battery through a converter. Why WiFi bursts trigger brownout resets, why a bare 18650 must never touch the 3V3 pin, and the wiring that keeps an ESP32 running.

Get a first live video stream from the ESP32-S3 CAM over plain USB-C — no FTDI adapter, no IO0 jumper — and fix the upload, stuck-IP and brownout errors that stop most beginners.

An HC-05 costs about the price of lunch and puts your Arduino on your Android phone: PIN 1234, a 1k/2k divider, one sketch. iPhone user? Read the first section before you buy.

If your SIM800L reboots the moment it searches for a network, the supply is the culprit. It needs 3.4–4.4V and 2A bursts — here is how to power it properly with an 18650 or an LM2596 buck.

Three wires and the Adafruit NeoPixel library get a WS2812 stick glowing from an Arduino Uno in minutes. The part everyone skips is the power budget — 60mA per LED at full white, which is why the 8×8 matrix needs its own 5V supply.