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Published August 31, 2026

ServeSync - Smart restaurant ordering and table management

Smart restaurant system using XIAO ESP32-S3 and ESP-NOW for digital ordering, food status notifications, and table cleaning alerts.

IntermediateProtipOver 2 days12

ServeSync - Smart restaurant ordering and table management

Things used in this project

Hardware components

Seeed Studio XIAO ESP32S3

Rotary Encoder with Push-Button

12×12 mm 4-Pin Tactile Push Button Switch (Red)

Tactile Switch, Top Actuated

LED (generic)

Solderless Breadboard Full Size

Resistor 330 ohm

Jumper wires (generic)

Software apps and online services

Microsoft Visual Studio Code Extension for Arduino

Story

🍽️ ServeSync – Smart Restaurant Ordering and Table Management System

📖 In troduction

Restaurants often face problems during busy hours because communication between customers, waiters, kitchen staff, and cleaning staff takes time.

Customers may need to wait for a waiter to place an order. Kitchen staff need to manage food preparation for multiple tables, while restaurant staff also need to know when customers have finished eating and when tables need cleaning.

For ServeSync, the XIAO ESP32-S3 is particularly valuable because its wireless capability enables direct ESP-NOW communication, while its GPIO resources allow us to interface the LEDs, push buttons, and rotary encoder required for the restaurant workflow. This gives us a compact, responsive, and scalable hardware node that can be replicated across tables while keeping the physical footprint small. The XIAO's Arduino compatibility also allowed rapid development and testing of the prototype.

This makes the XIAO ESP32-S3 more than just the controller of the project—it acts as the communication and interaction layer connecting the customer table with restaurant staff.

ServeSync is a smart restaurant automation prototype designed to improve this workflow.

The project combines:

📱 Software-based food ordering
📡 ESP-NOW wireless communication
🎛️ Rotary encoder table selection
💡 LED notifications
🔘 Customer interaction buttons
🧹 Table cleaning alerts

The system creates a communication link between customers and restaurant staff.

💡 In spiration

The main inspiration behind ServeSync was the problem of inefficient communication inside restaurants.

In a traditional restaurant:

This process can create delays and increase the workload of restaurant staff.

We wanted to create a smarter workflow where technology helps communicate important information automatically.

ServeSync allows:

Customers to place orders digitally.
Staff to manage food preparation status.
Customers to receive visual status notifications.
Customers to notify staff when they have finished eating.
Staff to receive a cleaning alert.

1. Project Overview

ServeSync – Smart Restaurant Ordering and Table Management

ServeSync is a smart restaurant management system designed to improve the interaction between customers and kitchen staff. The system combines a web-based food ordering interface with XIAO ESP32-S3 boards communicating through ESP-NOW.

For this demonstration, the system is configured for one customer table. A customer can place an order through the web interface, while the kitchen/staff side receives the order and can provide status updates. The system also supports service-related notifications, such as requesting table cleaning.

Overall ServeSync system / prototype

2. Problem Statement

Traditional restaurant ordering can require customers to wait for staff to take their orders. This can result in delays, communication errors, and additional workload for restaurant employees.

There is also a need for a simple way for customers to notify staff when they require assistance, such as requesting table cleaning or service.

ServeSync addresses these problems by combining a web-based ordering interface with wireless communication between XIAO ESP32-S3 devices.

3. Our Solution

ServeSync provides a simple digital ordering and restaurant service system.

Customers use a digital interface to:

View the menu.
Select food.
Select quantity.
Place an order.

with:

HTML – webpage structure
CSS – interface design and styling
JavaScript – ordering functionality and interaction

The hardware side uses XIAO ESP32-S3 boards. Communication between the customer-side and kitchen/staff-side boards is handled using ESP-NOW, allowing the devices to communicate wirelessly without requiring a traditional Wi-Fi network connection between them.

Hardware Communication System

ESP32 boards communicate wirelessly using ESP-NOW.

The hardware system handles:

Table selection.
Cooking status.
Ready status.
Customer notification.
Finished eating notification.
Cleaning alerts.

Customer ordering webpage

4. How the System Works

For the one-table demonstration, the system consists of two XIAO ESP32-S3 boards:

The basic workflow is:

The customer accesses the ordering webpage.
The customer selects food items and places an order.
The order information is processed by the system.
The customer-side XIAO ESP32-S3 communicates with the kitchen/staff XIAO ESP32-S3 using ESP-NOW.
The kitchen/staff side receives the order notification.
Staff can monitor the order and respond to customer/service requests.
The system can also provide notifications for table service or cleaning.

ESP-NOW communication between the two XIAO ESP32-S3 boards

https://youtube.com/shorts/g9OPB16NIxQ?si=GE2qJaZDzi-YHjth

5. Demo Configuration

This project is presented as a working prototype demonstration using one table (Table 1).

The full concept can be expanded to support multiple tables, but the current demonstration intentionally uses only one customer table to keep the prototype simple and easy to demonstrate.

Demo hardware

2 × Seeed Studio XIAO ESP32-S3

2× Tactile push button

2× Generic LED

2× Resistor

2× Breadboard

Jumper wires

Physical prototype on breadboard

Hardware Setup & Circuit

ServeSync is built as a two-node restaurant communication system using Seeed Studio XIAO ESP32-S3 boards and ESP-NOW wireless communication. For this demonstration, one Customer Unit (Table 1) and one Staff/Kitchen Unit are used.

Customer Unit — Table 1

The customer-side XIAO ESP32-S3 handles the table's order-status indication and the Finished button.

P4 → 330Ω resistor → LED positive (+) → LED negative (−) → GND

The LED provides visual feedback for the customer/order status.
A 330Ω resistor is used to limit the LED current.
P4 → 330Ω resistor → LED positive (+) → LED negative (−) → GNDThe LED provides visual feedback for the customer/order status.A 330Ω resistor is used to limit the LED current.

P5 → tactile push button → GND

The button allows the customer to signal that the order has been finished/collected.
P5 → tactile push button → GNDThe button allows the customer to signal that the order has been finished/collected.

Staff / Kitchen Unit

The staff-side XIAO ESP32-S3 receives customer notifications and provides controls for food status and table-cleaning alerts.

P5 → 330Ω resistor → LED positive (+) → LED negative (−) → GND

The LED indicates the relevant staff/table alert status.
A 330Ω current-limiting resistor is connected in series with the LED.
P5 → 330Ω resistor → LED positive (+) → LED negative (−) → GNDThe LED indicates the relevant staff/table alert status.A 330Ω current-limiting resistor is connected in series with the LED.

P4 → tactile push button → GND

Used by staff to update the food/order status.
P4 → tactile push button → GNDUsed by staff to update the food/order status.

Rotary Encoder

A rotary encoder is connected to the Staff/Kitchen XIAO ESP32-S3:

Encoder Pin XIAO ESP32-S3

A (CLK) P32

B (DT) P33

Common GND

SW1 P25

SW2 GND

The encoder provides an additional physical control interface for the staff unit.

Breadboard & Wiring

Both units are assembled on standard solderless breadboards for easy prototyping and testing. Jumper wires are used to connect the XIAO ESP32-S3 boards, LEDs, 330Ω resistors, tactile switches, rotary encoder, and ground connections.

The demonstration uses one customer table, so only two XIAO ESP32-S3 boards are required: one for the Customer Unit and one for the Staff/Kitchen Unit.

Wireless Communication

The two XIAO ESP32-S3 boards communicate wirelessly using ESP-NOW, allowing customer and staff notifications to be exchanged without requiring a conventional Wi-Fi connection between the two nodes.

How It Works

ServeSync combines a QR-code-based restaurant ordering system with two XIAO ESP32-S3 boards communicating through ESP-NOW.

Each restaurant table has its own unique QR code. When a customer scans the QR code at their table, they are taken directly to the digital ordering interface for that table.

Step 1 – Customer Places an Order

Each table in the restaurant is assigned a unique QR code.

The customer scans the QR code using their smartphone. The QR code opens the restaurant's web-based ordering system and identifies the table from which the order is being placed.

For example:

TABLE 1 → TABLE 1 QR CODETABLE 2 → TABLE 2 QR CODETABLE 3 → TABLE 3 QR CODETABLE 4 → TABLE 4 QR CODE

For this prototype demonstration, Table 1 is used.

After scanning the QR code, the customer can:

View available food items
Select food
Select quantity
Review the order
Place the order

The ordering interface is developed using HTML, CSS, and JavaScript.

📱 QR-CODE ORDERING SYSTEM

4 unique QR code of 4 tables

staff dashboard

customer dashboard

order confirmation for customer

Software Features

Unique QR code for each table
Digital food menu
Food selection
Quantity selection
Order placement
Table identification through QR code
Reduced dependency on manual order taking

Step 2 – Staff Selects a Table

The Kitchen/Staff XIAO ESP32-S3 contains a rotary encoder.

The encoder allows staff to select the table they want to manage:

TABLE 1TABLE 2TABLE 3TABLE 4

The selected table is shown in the Serial Monitor.

Example:

TABLE 1
TABLE 1

Rotating the encoder changes the active table.

Pressing the encoder button confirms the selection.

Example:

SELECTED TABLE 2
SELECTED TABLE 2

🎛️ ROTARY ENCODER

Step 3 – Food Status Changes to Cooking

After selecting the required table, the staff presses the P4 button.

The food status changes to:

COOKING

The Staff XIAO ESP32-S3 sends:

MSG_COOKING = 10
MSG_COOKING = 10

The message contains:

[Message Type, Table Number]
[Message Type, Table Number]

Example:

[10, 1]
[10, 1]

This means:

TABLE 1 → COOKING

🔥 COOKING STATUS

The Customer XIAO ESP32-S3 receives the ESP-NOW message.

If the received table number matches its configured table number, the customer notification LED connected to P4 starts blinking.

Example:

TABLE 1
FOOD STATUS = COOKING
CUSTOMER P4 LED = BLINKING
TABLE 1
FOOD STATUS = COOKING
CUSTOMER P4 LED = BLINKING

This gives the customer a visual indication that their order is currently being prepared.

📸 COOKING NOTIFICATION

cooking status

blinking customer led when the staff send cooking message

Step 4 – Food Status Changes to Ready

When the food is prepared, the staff presses the food-status button again.

The status changes:

COOKING
   ↓
READY
COOKING
   ↓
READY

The Staff XIAO ESP32-S3 sends:

MSG_READY = 11
MSG_READY = 11

Example:

[11, 1]
[11, 1]

The Customer XIAO ESP32-S3 receives the message.

The customer notification LED turns OFF.

Example:

TABLE 1
FOOD STATUS = READY
CUSTOMER P4 LED = OFF
TABLE 1
FOOD STATUS = READY
CUSTOMER P4 LED = OFF

✅ READY STATUS

status of food in customers

Step 6 – Staff Receives Cleaning Alert

When the Staff XIAO ESP32-S3 receives the Finished message:

TABLE 1 NEEDS CLEANING
TABLE 1 NEEDS CLEANING

The system stores the cleaning request:

tableNeedsCleaning[1] = true;
tableNeedsCleaning[1] = true;

The Staff LED connected to P5 starts blinking.

Example Serial Monitor output:

==============================
CUSTOMER FINISHED - TABLE 1 NEEDS CLEANING
STAFF P5 LED = BLINKING
==============================
==============================
CUSTOMER FINISHED - TABLE 1 NEEDS CLEANING
STAFF P5 LED = BLINKING
==============================

🧹 CLEANING ALERT

staff dashboard

staff led

Step 7 – Staff Cleans the Table

The staff rotates the encoder and selects the table that requires cleaning.

Example:

SELECTED TABLE 1
SELECTED TABLE 1

After cleaning the table, the staff presses the P4 button to acknowledge that cleaning has been completed.

The system then:

Removes the cleaning request
Resets the table status
Stops the cleaning alert when there are no remaining cleaning requests

Example:

==============================
TABLE 1 CLEANED
STAFF P5 LED = OFF
==============================
==============================
TABLE 1 CLEANED
STAFF P5 LED = OFF
==============================

The table is now ready for the next customer.

🔄 Complete ServeSync Workflow

complete workflow

📌 Communication Overview

Code

kitchen - staff arduino code

#include <WiFi.h>
#include <esp_now.h>
#include "esp_mac.h"
#include <esp_wifi.h>

// ============================================
// ENCODER PINS
// ============================================
#define CLK 32
#define DT  33
#define SW  25

// ============================================
// STAFF PINS
// ============================================
// P4 = Food Control Button
// P5 = Cleaning Alert LED
#define STAFF_BUTTON_PIN 4
#define STAFF_LED_PIN    5

// ============================================
// DESTINATION MAC ADDRESSES
// ============================================
uint8_t broadcastMAC[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
uint8_t customerMAC[]  = { 0xB0, 0xCB, 0xD8, 0x09, 0x4B, 0x54 };

// ============================================
// MESSAGE TYPES
// ============================================
#define MSG_COOKING          10
#define MSG_READY            11
#define MSG_TABLE_FINISHED   12

// ============================================
// TABLE FOOD STATUS (Per Table 1-4)
// ============================================
int tableStatus[5] = { 0, 0, 0, 0, 0 };

// ============================================
// TABLE CLEANING STATUS (Per Table 1-4)
// ============================================
bool tableNeedsCleaning[5] = { false, false, false, false, false };

// ============================================
// ENCODER & SELECTION STATES
// ============================================
int selectedTable  = 1;
int confirmedTable = 1;
int lastCLK = HIGH;

// ============================================
// STAFF P5 LED CLEANING ALERT STATE
// ============================================
bool cleaningAlert      = false;
bool staffLEDState      = false;
unsigned long lastStaffLEDChange = 0;

// ============================================
// INCOMING DATA PROCESSING
// ============================================
void processIncomingData(const uint8_t *data, int len) {
  if (len < 2) return;

  uint8_t msg           = data[0];
  uint8_t receivedTable = data[1];

  if (msg == MSG_TABLE_FINISHED) {
    if (receivedTable >= 1 && receivedTable <= 4) {
      tableNeedsCleaning[receivedTable] = true;
      cleaningAlert  = true;
      staffLEDState  = true;
      digitalWrite(STAFF_LED_PIN, HIGH);
      lastStaffLEDChange = millis();

      Serial.println();
      Serial.println("==============================");
      Serial.print("CUSTOMER FINISHED - TABLE ");
      Serial.print(receivedTable);
      Serial.println(" NEEDS CLEANING");
      Serial.println("STAFF P5 LED = BLINKING");
      Serial.println("==============================");
      Serial.println();
    }
  }
}

#if defined(ESP_ARDUINO_VERSION_MAJOR) && ESP_ARDUINO_VERSION_MAJOR >= 3
void OnDataRecv(const esp_now_recv_info_t *info, const uint8_t *data, int len) {
  processIncomingData(data, len);
}
#else
void OnDataRecv(const uint8_t *mac, const uint8_t *data, int len) {
  processIncomingData(data, len);
}
#endif

// ============================================
// SEND FOOD STATUS VIA ESP-NOW
// ============================================
void sendFoodStatus(uint8_t table, uint8_t message) {
  uint8_t payload[2];
  payload[0] = message;
  payload[1] = table;

  esp_now_send(broadcastMAC, payload, sizeof(payload));
  esp_now_send(customerMAC,  payload, sizeof(payload));
  esp_now_send(NULL,         payload, sizeof(payload));

  if (message == MSG_COOKING) {
    Serial.println();
    Serial.print("TABLE ");
    Serial.print(table);
    Serial.println(" -> COOKING");
  } else if (message == MSG_READY) {
    Serial.println();
    Serial.print("TABLE ");
    Serial.print(table);
    Serial.println(" -> READY");
  }
}

// ============================================
// SETUP
// ============================================
void setup() {
  Serial.begin(115200);
  delay(500);

  pinMode(CLK, INPUT_PULLUP);
  pinMode(DT,  INPUT_PULLUP);
  pinMode(SW,  INPUT_PULLUP);
  lastCLK = digitalRead(CLK);

  pinMode(STAFF_BUTTON_PIN, INPUT_PULLUP);
  pinMode(STAFF_LED_PIN, OUTPUT);
  digitalWrite(STAFF_LED_PIN, LOW);

  WiFi.mode(WIFI_STA);
  WiFi.disconnect();
  esp_wifi_set_channel(1, WIFI_SECOND_CHAN_NONE);

  uint8_t kitchenMAC[6];
  esp_read_mac(kitchenMAC, ESP_MAC_WIFI_STA);

  Serial.println();
  Serial.println("==============================");
  Serial.println("KITCHEN / STAFF ESP32");
  Serial.println("==============================");
  Serial.printf("Kitchen MAC: %02X:%02X:%02X:%02X:%02X:%02X\n",
    kitchenMAC[0], kitchenMAC[1], kitchenMAC[2],
    kitchenMAC[3], kitchenMAC[4], kitchenMAC[5]);

  if (esp_now_init() != ESP_OK) {
    Serial.println("ESP-NOW INIT FAILED");
    return;
  }

  esp_now_register_recv_cb(OnDataRecv);

  esp_now_peer_info_t peerInfo = {};
  memcpy(peerInfo.peer_addr, broadcastMAC, 6);
  peerInfo.channel = 1;
  peerInfo.encrypt = false;
  esp_now_add_peer(&peerInfo);

  esp_now_peer_info_t customerPeer = {};
  memcpy(customerPeer.peer_addr, customerMAC, 6);
  customerPeer.channel = 1;
  customerPeer.encrypt = false;
  esp_now_add_peer(&customerPeer);

  Serial.println("KITCHEN ESP-NOW READY");
  Serial.println("P4 = FOOD STATUS BUTTON");
  Serial.println("P5 = CLEANING ALERT LED");
  Serial.println("ENCODER = 32 / 33 / 25");

  Serial.print("TABLE ");
  Serial.println(selectedTable);
}

// ============================================
// MAIN LOOP
// ============================================
void loop() {
  unsigned long now = millis();

  // P5 LED BLINKING (CLEANING ALERT)
  if (cleaningAlert) {
    if (now - lastStaffLEDChange >= 500) {
      lastStaffLEDChange = now;
      staffLEDState = !staffLEDState;
      digitalWrite(STAFF_LED_PIN, staffLEDState);
    }
  }

  // ENCODER ROTATION
  int currentCLK = digitalRead(CLK);
  if (currentCLK != lastCLK) {
    if (digitalRead(DT) != currentCLK) {
      selectedTable++;
    } else {
      selectedTable--;
    }
    if (selectedTable > 4) selectedTable = 1;
    if (selectedTable < 1) selectedTable = 4;
    confirmedTable = selectedTable;
    Serial.print("TABLE ");
    Serial.println(selectedTable);
    delay(100);
  }
  lastCLK = currentCLK;

  // ENCODER BUTTON
  if (digitalRead(SW) == LOW) {
    delay(50);
    if (digitalRead(SW) == LOW) {
      confirmedTable = selectedTable;
      Serial.print("SELECTED TABLE ");
      Serial.println(confirmedTable);
      while (digitalRead(SW) == LOW) delay(10);
      delay(100);
    }
  }

  // STAFF P4 BUTTON (FOOD CONTROL / CLEAN ACK)
  if (digitalRead(STAFF_BUTTON_PIN) == LOW) {
    delay(50);
    if (digitalRead(STAFF_BUTTON_PIN) == LOW) {
      int activeTargetTable = (confirmedTable >= 1 && confirmedTable <= 4)
                              ? confirmedTable : selectedTable;

      if (tableNeedsCleaning[activeTargetTable]) {
        tableNeedsCleaning[activeTargetTable] = false;

        bool anyPending = false;
        for (int i = 1; i <= 4; i++) {
          if (tableNeedsCleaning[i]) anyPending = true;
        }
        if (!anyPending) {
          cleaningAlert  = false;
          staffLEDState  = false;
          digitalWrite(STAFF_LED_PIN, LOW);
        }
        tableStatus[activeTargetTable] = 0;

        Serial.println();
        Serial.println("==============================");
        Serial.print("TABLE ");
        Serial.print(activeTargetTable);
        Serial.println(" CLEANED");
        Serial.println("STAFF P5 LED = OFF");
        Serial.println("==============================");
        Serial.println();

      } else {
        int currentStatus = tableStatus[activeTargetTable];
        if (currentStatus == 2) {
          tableStatus[activeTargetTable] = 3;
          sendFoodStatus(activeTargetTable, MSG_READY);
        } else {
          tableStatus[activeTargetTable] = 2;
          sendFoodStatus(activeTargetTable, MSG_COOKING);
        }
      }

      while (digitalRead(STAFF_BUTTON_PIN) == LOW) delay(10);
      delay(100);
    }
  }

  delay(10);
}

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ServeSync - Smart restaurant ordering and table management

ServeSync - Smart restaurant ordering and table management

Things used in this project

Hardware components

Software apps and online services

Story

🍽️ ServeSync – Smart Restaurant Ordering and Table Management System

📖 In troduction

💡 In spiration

1. Project Overview

ServeSync – Smart Restaurant Ordering and Table Management

2.

Problem Statement

3. Our Solution

Hardware Communication System

4. How the System Works

5. Demo Configuration

Demo hardware

Hardware Setup & Circuit

Customer Unit — Table 1

Staff / Kitchen Unit

Rotary Encoder

Breadboard & Wiring

Wireless Communication

How It Works

📱 QR-CODE ORDERING SYSTEM

Software Features

Step 2 – Staff Selects a Table

🎛️ ROTARY ENCODER

Step 3 – Food Status Changes to Cooking

🔥 COOKING STATUS

📸 COOKING NOTIFICATION

Step 4 – Food Status Changes to Ready

✅ READY STATUS

Step 6 – Staff Receives Cleaning Alert

🧹 CLEANING ALERT

Step 7 – Staff Cleans the Table

Schematics

circuit diagram

servesync - circuit diagram

Code

kitchen - staff arduino code

Kitchen/Staff XIAO ESP32-S3 – ESP-NOW Control

Credits

Haniya

Farha

Fahmiyaa Sadath

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