Introduction: Mmm…Savor Every Mouthful With Your Loved Ones

About: I am an interaction designer and love physical computing.

This project is an LED candle at the dinner table for a couple to savor food with each other. I made this product because I usually eat five times faster than my wife. I never stop using chopsticks, and we don’t talk to each other while eating food. However, this LED candle induces a couple to eat at the same time. It is connected to a pair of chopstick rests. Each chopstick rest detects a pair of chopsticks is being used or not with an infrared proximity sensor.

It has three states:

1. If two pairs of chopsticks are on the rest (two people are not eating), the LED candle turns on.

2. If two pairs of chopsticks are not on the rest (two people are eating), the LED candle turns on.

3. If only one pair of chopsticks is on the rest (one person is eating), the LED candle turns off.

  • In Korean cuisine context, chopstick rest is a tableware for keeping chopstick tips off the table and to prevent used chopsticks from contaminating or rolling off tables. When people don't use chopsticks, they put them on the rest during eating food.
  • Full Story link:

Step 1: ​Go Get Stuff

You will need:



  • Soldering kits
  • Knitting kits
  • 3D Printer (NOTE: The enclosure of this project is made with a 3D printer.)
  • Saw

Step 2: ​Solder

Attach the Arduino Nano to the center of the PCB board.

A. Infrared proximity sensor

The infrared proximity sensor has three wires. Extend the original wire by adding 20 cm (Approx. 8 inches) more wire to make sure each chopstick rest has enough length. The red wires connect to the 5V pin. To do this, use the stripped wire go through the adjacent PCB board holes of a 5V pin. Connect the wires with soldering. Connect the wires to 5V pin with soldering. The black wire connects to GND pin. Do the same things with the red wires. The yellow wire connects to an analog pin. The yellow wire of the first sensor connects to A1 pin, and the same wire of the second sensor connects to A2 pin.


The RGB LED has four legs. The second leg is the long one. Solder each RGB leg to a 220Ω resistor and connect the wires to each digital pin.

  • The first leg (red) connects to D7 pin.
  • The second leg (power) connects to 5V pin.
  • The third leg is a (green) color and connects to D8 pin.
  • The fourth leg is a blue color and connects to D9 pin.

C. 9V battery case

It has two wires. The red wire is for "+" and the black wire is for "-." Connect the red wire to VIN pin and connect the black wire to GND pin.

Step 3: ​Code

Download the file and upload the code to the Arduino Nano through the Arduino program on your computer. If you don't have the program, follow the instructions below.

  1. Download the Arduino program on your computer first (download here).
  2. Download and click the "Mmm_code_final.ino" file.
  3. Connect the Arduino Nano to the computer with a USB cable.
  4. Change settings: "Tools > Board: Arduino Nano."
  5. Press "->" button to upload the code to your Nano.

The code operates as follows.

  • If two infrared proximity sensors detect an object, the LED turns on.
  • If two infrared proximity sensors don't detect an object, the LED turns on.
  • If one infrared proximity sensor detects an object, the LED turns off.

Step 4: Cut and Polish the Wood

For the chopstick rest component, I used wood, but you can use any material. First, cut two blocks of wood to 50 x 36 x 18 mm. Then, measure the sensor's size and make a hole in the wood to insert the sensor. Polish the wood like a pebble and make a recess for the chopsticks. Add wood filler to fill the cracks between the wood and sensor. Don't cover the sensor part.

Step 5: 3D Print

NOTE: If you don't have an access to 3D printer, you can use any materials for the enclosure.

Download and use the file to make a LED candle product. I designed it with Rhinoceros. I used a white filament for the bottom part and a transparent filament for the upper part.

Step 6: Knit a Wire Cover

There are many ways to knit the wire. Please check the tutorial below and find your own way. I used a red yarn for knitting.

1. Crochet

2. Without needle

Step 7: Enjoy

Mihaly Csikszentmihalyi states that "In modern society, there are many possibilities to discontinue the relationships." The family is the most fundamental social unit. However, modern technology has contributed to more distance between family. With this project, you can sit back and savor every mouthful with your loved one and enhance your relationship.

Epilog Challenge 9

Participated in the
Epilog Challenge 9

Arduino Contest 2017

Participated in the
Arduino Contest 2017

LED Contest 2017

Participated in the
LED Contest 2017