This is a smart table based on the Arduino code. You can edit code by yourself make it smarter.

This is basically a Proximity sensor. A proximity sensor is a sensor that is used in our cellphone to detect the presence of a human ear.

Story

he is basically a Proximity sensor. The proximity sensor is the sensor that is used in our cellphone to detect the presence of a human ear. This sensing is done for two purposes: Reduce display power consumption by turning off the LCD backlight and to disable the touch screen to avoid inadvertent touches by the cheek.

Here we have used the same circuit but get the opposite output. In a mobile phone, it helps to turn on the screen but here, in the Smart Table, we used the circuit to detect the elements placed on the tabletop and indicate its position by turning ON the LEDs of those particular places.

A proximity sensor often emits an electromagnetic field or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal.

Anyone can adjust the length of infrared rays for the table by varying the value of 10k Potentiometers.

I have connected the circuit board to each other in a parallel manner. Used 5v 20-40 amp SMPS for power supply.

Arduino Smart table
        // /* This is the code for Arduino UNO used in the 'Smart Relay' part of the 'Smart Table Assistant project' built for the 
 *  'Smart Homes on the Edge' contest conducted by Hackster.io and sponsored by Seeed and Snips.
 * 
 * Contest Page - https://www.hackster.io/contests/building-for-voice
 * 
 * Blog Link - 
 * 
 * Author : Dixon Selvan
 * Date   : April 11, 2019
 * Project: Smart Table Assitant
 * Website: 
 * 
 * Hardware components Required
 * ----------------------------------------
 * 1. Arduino UNO board
 * 2. Four Channel Relay Module
 * 3. Arduino MKR1000
 * 4. Few Jumper wires
 * 
 * Connections
 * -----------
 * Arduino UNO      |   Relay Module
 * ---------------------------------------------
 *      5V          |         VCC
 *      Gnd         |         Gnd
 *      IN1         |         D10     
 *      IN2         |         D11
 *      IN3         |         D5
 *      IN4         |         D6
 * Arduino UNO      |   Arduino MKR1000
 * ---------------------------------------------
 *      Vin         |         +5V
 *      Gnd         |         Gnd
 *      RX          |         TX     
 *      TX          |         RX
 * 
 */
 
int Relay1 = 10;
int Relay2 = 11;
int Relay3 = 5;
int Relay4 = 6;
int serialData = 0;

void setup() {
  // put your setup code here, to run once:
  pinMode(Relay1, OUTPUT);
  pinMode(Relay2, OUTPUT);
  pinMode(Relay3, OUTPUT);
  pinMode(Relay4, OUTPUT);
  Serial.begin(38400);
  digitalWrite(Relay1, HIGH);
  digitalWrite(Relay2, HIGH);
  digitalWrite(Relay3, HIGH);
  digitalWrite(Relay4, HIGH);
}

void loop() {
  // put your main code here, to run repeatedly:
  if(Serial.available()>0){
     serialData = Serial.read();
     Serial.println(serialData);
     if (serialData == 49){
      digitalWrite(Relay1, LOW);
     }
     else if (serialData == 50){
      digitalWrite(Relay1, HIGH);
     }
     else if (serialData == 51){
      digitalWrite(Relay2, LOW);  
     }
     else if (serialData == 52){
      digitalWrite(Relay2, HIGH); 
     }
     else if (serialData == 53){
      digitalWrite(Relay3, LOW);
     }
     else if (serialData == 54){
      digitalWrite(Relay3, HIGH);
     }
     else if (serialData == 55){
      digitalWrite(Relay4, LOW);  
     }
     else if (serialData == 56){
      digitalWrite(Relay4, HIGH); 
     }
  }
}
Smart Table Assistant - GitHub Repository