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Holiday season is almost here, which means it time to make something that lights up. As part of this project, we are making a Light up Coaster using an Arduino Nano, LED strip and a grove sound sensor. The coaster changes colour as soon as it hears some sound/music playing.


Here are the steps to follow, to make the coaster

Download and 3D print the STL files attached

There are 2 STL files attached in the zip file below, You can print this coasterBottom.stl file using a coloured filament and the coasterTop.stl using a transparent filament to help with the diffusion of the APA102 LED strip.

Soldering the circuit together

Now for the circuit we will need an Arduino Nano, LED strip APA102 and a Grove sound sensor. Here are the connections to the Arduino Nano

  • apa102 led strip Data  connected to Arduino pin# 11
  • apa102 clock connected to Arduino pin# 12
  • Sound sensor connected to A0


Once done hotglue the Arduino, Sound sensor and LED strip to the 3D printed parts.


Upload the Arduino code

Now download latest Arduino IDE, and upload the sketch below to the Arduino IDE. Before uploading the sketch you will also need the APA102 Arduino library from

//Created for Project14 Coaster using APA102 and Grove sound sensor 
//Download the APA102 libary from -
#include <APA102.h>  
// Define which pins to use.  
const int pinAdc = A0;  
const uint8_t dataPin = 11;  
const uint8_t clockPin = 12;  
APA102<dataPin, clockPin> ledStrip;  
// Set the number of LEDs to control, till will depend on how many you want to add to the coaster 
const uint16_t ledCount = 10;  
//Create a buffer for holding the colors (3 bytes per color).  
rgb_color colors[ledCount];  
// Set the brightness to use (the maximum is 31).  
const uint8_t brightness = 20;  
const uint8_t delayTimes = 100;
uint8_t ared =255, bgreen =255, cblue=255; 
void setup()  
void loop()  
long vol = 0;   
vol = analogRead(pinAdc);
// change the condition values of the vol based on the output of the serial monitor.
    ared =0, bgreen =0, cblue=255;
else if(vol>=100 && vol<150)
    ared =0, bgreen =255, cblue=0;
else if(vol>=150)
    ared =255, bgreen =0, cblue=0;
    ared =255, bgreen =255, cblue=255;
for(uint16_t i = 0; i < ledCount; i++)
  colors[i] = rgb_color(ared, bgreen, cblue); 
  ledStrip.write(colors, ledCount, brightness);


Here is a quick test of the circuit, and once done the top should snap fit to the bottom 3D printed part...


Here is a quick video demo.