MuTech RoboticsLearning Hub
Kids OK with adultESP32Level 2/3

Smart Rangoli That Lights Up When You Come Near

A rangoli outlined with addressable LEDs. A small distance sensor sees guests coming and the whole pattern glows to welcome them.

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Smart Rangoli That Lights Up When You Come Near
Kids OK, with an adult

DIY project. Children must build this only with an adult (16+ years) beside them at all times. Not suitable for children under 8 years.

Use a 5 V supply big enough for the strip, with a 1000 µF capacitor across it. Keep wires out of the walking path and away from diyas and candles.

Strictly follow the description given with this video.

Video

How it works

  1. A time-of-flight distance sensor watches the doorway.
  2. When someone comes within about 1.2 m, the ESP32 starts a lighting pattern.
  3. Its data signal goes through a level shifter and a 330 Ω resistor to the LED strip, so every LED gets clean 5 V data.
  4. When nobody is near, the rangoli settles back to a soft glow.

Parts you need

  • ESP32 development board (30-pin)ESP32 development board (30-pin)₹518× 1Buy
  • Time-of-flight distance sensor (VL53L0X)Time-of-flight distance sensor (VL53L0X)₹288× 1Buy
  • Addressable LED strip (WS2812B)× 1
  • Logic level shifter× 1
  • 330 Ω resistor330 Ω resistor₹0.57× 1Buy
  • 1000 µF capacitor1000 µF capacitor₹12× 1Buy
  • 5 V 3 A supply5 V 3 A supply₹253× 1Buy

Wiring

Distance sensorSDA / SCLVCCESP32I2C3V3data pinstrip DIN(Level shifter, 330 Ω)Strip 5V and ESP32VIN5 V supplyAcross the 5 V supply1000 µF capacitorCommon GNDAll grounds
PowerGroundSignal
#FromConnect to
1 SignalDistance sensor SDA / SCLESP32 I2C (D21 / D22)
2 PowerDistance sensor VCCESP32 3V3
3 SignalESP32 data pinLevel shifter → 330 Ω → strip DIN
4 Power5 V supplyStrip 5V and ESP32 VIN
5 Power1000 µF capacitorAcross the 5 V supply
6 GroundAll groundsCommon GND

3D print files

This project has no 3D-printed parts.

Code

The tested Arduino / ESP32 code for this project will be posted here, ready to copy.