Memoria Investigaciones en Ingeniería, núm. 28 (2025). pp. 154-167
https://doi.org/10.36561/ING.28.11
ISSN 2301-1092 • ISSN (en línea) 2301-1106 – Universidad de Montevideo, Uruguay
Este es un artículo de acceso abierto distribuido bajo los términos de una licencia de uso y distribución CC BY-NC 4.0. Para ver
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An IoT-Based Autonomous Waiter Robot
Un robot camarero autónomo basado en IoT
Um robô garçom autónomo baseado em IoT
Sadiq Ur Rehman
1
(*)
Recibido: 17/10/2024 Aceptado: 26/01/2025
Summary. - The widespread adoption of automation and robotics across various sectors has driven innovations in
service delivery, particularly in the hospitality industry. This paper presents the design, development, and
implementation of an IoT-based waiter robot aimed at enhancing efficiency and customer satisfaction in restaurants.
The robot employs an ESP32 microcontroller, ultrasonic sensors, and a touchscreen interface for autonomous
navigation, order processing, and food delivery. Unlike traditional path-planning approaches, this robot adapts
dynamically to its environment, offering flexibility and reliability in service. Detailed evaluations demonstrate the
system’s effectiveness in optimizing operations, reducing delays, and improving overall customer experience. The
proposed solution is cost-effective and scalable, making it suitable for diverse restaurant settings.
Keywords: IoT, ESP32, Robot, Automation, Ultrasonic Sensors, Real-time Navigation
(*) Corresponding author.
1
Ph.D., Assistant Professor, FEST, Hamdard University (Pakistan), sadiq.rehman@hamdard.edu.pk,
ORCID iD: https://orcid.org/0000-0002-6308-450X
S. Ur Rehman
Memoria Investigaciones en Ingeniería, núm. 28 (2025). pp. 154-167
https://doi.org/10.36561/ING.28.11
ISSN 2301-1092 • ISSN (en línea) 2301-1106 – Universidad de Montevideo, Uruguay 155
Resumen. - La adopción generalizada de la automatización y la robótica en varios sectores ha impulsado
innovaciones en la prestación de servicios, particularmente en la industria hotelera. Este artículo presenta el diseño,
desarrollo e implementación de un robot camarero basado en IoT destinado a mejorar la eficiencia y la satisfacción
del cliente en restaurantes. El robot emplea un microcontrolador ESP32, sensores ultrasónicos y una interfaz de
pantalla táctil para navegación autónoma, procesamiento de pedidos y entrega de alimentos. A diferencia de los
enfoques tradicionales de planificación de rutas, este robot se adapta dinámicamente a su entorno, ofreciendo
flexibilidad y confiabilidad en el servicio. Las evaluaciones detalladas demuestran la eficacia del sistema para
optimizar las operaciones, reducir los retrasos y mejorar la experiencia general del cliente. La solución propuesta es
rentable y escalable, lo que la hace adecuada para diversos entornos de restaurantes.
Palabras clave: IoT, ESP32, Robot, Automatización, Sensores ultrasónicos, Navegación en tiempo real.
Resumo. - A adoção generalizada da automação e da robótica em vários setores impulsionou inovações na prestação
de serviços, especialmente na indústria hoteleira. Este artigo apresenta o projeto, desenvolvimento e implementação
de um robô garçom baseado em IoT que visa aumentar a eficiência e a satisfação do cliente em restaurantes. O robô
emprega um microcontrolador ESP32, sensores ultrassônicos e uma interface touchscreen para navegação autônoma,
processamento de pedidos e entrega de alimentos. Ao contrário das abordagens tradicionais de planejamento de
trajetória, este robô se adapta dinamicamente ao seu ambiente, oferecendo flexibilidade e confiabilidade no serviço.
Avaliações detalhadas demonstram a eficácia do sistema na otimização das operações, na redução de atrasos e na
melhoria da experiência geral do cliente. A solução proposta é econômica e escalável, tornando-a adequada para
diversos ambientes de restaurantes.
Palavras-chave: IoT, ESP32, Robô, Automação, Sensores Ultrassônicos, Navegação em Tempo Real.
S. Ur Rehman
Memoria Investigaciones en Ingeniería, núm. 28 (2025). pp. 154-167
https://doi.org/10.36561/ING.28.11
ISSN 2301-1092 • ISSN (en línea) 2301-1106 – Universidad de Montevideo, Uruguay 156
1. Introduction. - Technological advancements have significantly transformed various industries, leading to the
integration of robots into daily operations. In healthcare, robots assist in delicate surgeries, while in manufacturing,
they optimize production lines from assembly to packaging [1, 2]. Recently, the service sector has embraced robotics,
introducing IoT-based waiter robots to revolutionize dining experiences in restaurants, coffee shops, and similar setups
[3]. These robots aim to improve order processing efficiency, ensure timely food delivery, and navigate safely through
congested aisles. Furthermore, they provide restaurant owners with opportunities to reduce operational costs and
enhance employee productivity, creating a seamless and technologically advanced customer experience [4].
Conventional food delivery systems in restaurants rely heavily on human labor, resulting in inefficiencies such as
delayed service, order mix-ups, and high operating costs. These limitations underscore the need for automated
solutions. Leveraging IoT technology enables real-time data transfers, paving the way for autonomous systems capable
of performing tasks without human intervention [5-9]. This study proposes an IoT-based waiter robot to address these
challenges by integrating advanced navigation algorithms, real-time obstacle avoidance, and decision-making
processes. Table 1 compares existing waiter robots, emphasizing their features and limitations.
Feature
Robo Waiter
Savioke Relay
Bear Robotics
Penny
Pudu Bot
Bella Bot
Manufacturer
Robo Waiter
Savioke
Bear Robotics
Pudu Tech
Pudu Tech
Country
Denmark
USA
USA
China
China
Navigation
System
Lidar
Lidar, Camera
Lidar, Camera
Lidar, Camera
Lidar, Camera
Interaction
Method
Buttons
Touch Screen
Touch Screen,
Voice
Touch Screen
Touch Screen,
Voice
Payload
Capacity
2 kg
5 kg
12 kg
30 kg
10 kg
Battery Life
8 hours
24 hours
12 hours
10-12 hours
12-16 hours
Charging Time
2 hours
2 hours
4 hours
4 hours
4 hours
Max Speed
0.5 m/s
1.1 m/s
0.9 m/s
1.2 m/s
1.2 m/s
Obstacle
Detection
Basic IR
sensor
Advanced
sensor
Advanced sensor
Advanced sensor
Advanced
sensor
Connectivity
Bluetooth
Wi-Fi
Wi-Fi, Bluetooth
Wi-Fi
Wi-Fi
Cost
Low
High
Medium
Medium
Medium
Additional
Features
Basic voice
responses
Can call the
elevator, SLA
Advanced voice
recognition
Multi-robot
collaboration
Facial
recognition,
AI
Application
Simple table
service
Hotel service,
Delivery
Restaurant service
Restaurant
service
Restaurant
service
Table I. Comparison table for different bots
Following are the key contributions of our work.
1. Combining IoT technologies with robotics and real-time data processing.
2. Significantly improves service efficiency and reduces operational delays.
3. Features a scalable architecture that adapts to various restaurant sizes and needs.
Recent advancements in waiter robots reflect substantial progress in automation, efficiency, and technology
integration. Table 2. Demonstrate the comparative analysis of significant studies and technological improvement in
comparison to the proposed model
Limitations
Proposed Work
Robots followed only designated paths with
IR sensor arrays; and high-voltage HUB
motors.
Utilized lithium-ion batteries for better energy
efficiency; implemented advanced mapping for
improved navigation.
Used RFID tags for table identification.
Adopted advanced mapping for flexible and
efficient table navigation.
S. Ur Rehman
Memoria Investigaciones en Ingeniería, núm. 28 (2025). pp. 154-167
https://doi.org/10.36561/ING.28.11
ISSN 2301-1092 • ISSN (en línea) 2301-1106 – Universidad de Montevideo, Uruguay 157
RFID is used for order management, but it
has limited obstacle-detection and path-
finding capabilities.
Enhanced with ultrasonic sensors for obstacle
detection; used mapping for path finding;
integrated order processing and billing.
Designed an IoT-based robot with real-time
tracking and mobile app control.
Showcased ESP32’s real-time capabilities and
ease of integration with mobile apps.
Table II. Comparative analysis of significant studies and technological improvement
The remainder of this paper is organized as follows: Section II describes the Proposed Architectural Model and
Methodology of the system. Section III presents the results and discussion, highlighting the system's performance.
Finally, Section IV concludes the paper with a summary of the key findings and the implications for the future of
automated restaurant services.
2. Proposed Architectural Model and Methodology. - The development of the IoT-based waiter robot involved a
series of well-structured steps to ensure its efficiency and reliability. The robot's architecture and specifications are
illustrated in the block diagram in Figure I and the system process diagram in Figure III.
2.1 System Overview. - The IoT-based waiter robot’s architecture integrates hardware and software components to
ensure autonomous navigation and efficient task execution. For the robot, the ESP32 microcontroller [14] is used for
its multi-functionality and an in-built Wi-Fi module which is very essential in IoT and is used to control robots,
appliances, and other attributes to ensure perfect interaction between the robot, the kitchen, and the customers.
For navigation and obstacle detection purposes, the robot uses ultrasonic sensors with a range of up to 21 meters which
allows the robot to smoothly operate at the restaurants. Further, using the TCRT5000 infrared sensor [15], the robot
can identify when the trays placed for the customer's food have been taken and only then return to the kitchen.
Figure I. Block Diagram
The robot has a touch-based LCD, with ESP32 (connections can be seen in Figure II) at the customer interface and the
kitchen interface. In the kitchen, such a display gives instructions to the robot to move to the customer's table to take
an order. Once at the customer's table, the robot provides the customer with the menu where the customer makes his/her
order which is sent back to the kitchen through the WiFi. The chef then prepares the order and places it on the robot's
tray.
Figure II. Connection of ESP 32 with TOUCH LCD
S. Ur Rehman
Memoria Investigaciones en Ingeniería, núm. 28 (2025). pp. 154-167
https://doi.org/10.36561/ING.28.11
ISSN 2301-1092 • ISSN (en línea) 2301-1106 – Universidad de Montevideo, Uruguay 158
Upon order completion, the chef commands the robot to deliver the meal to the customer. The robot uses its ultrasonic
sensors to navigate, halting if an obstacle is detected until the path is clear. After the customer takes their meal, detected
by the TCRT5000 sensor, the robot returns to its initial position in the kitchen, ready for the next task.
Figure III. System Process Diagram
The robot is powered by a 24V lithium-ion battery, which provides energy to the DC-geared motors [16] through a 4-
channel relay module. The relay module, connected to the ESP32, allows precise control of the robot's movements (see
Figure IV).
Figure IV. Connection of ESP 32 with relay
S. Ur Rehman
Memoria Investigaciones en Ingeniería, núm. 28 (2025). pp. 154-167
https://doi.org/10.36561/ING.28.11
ISSN 2301-1092 • ISSN (en línea) 2301-1106 – Universidad de Montevideo, Uruguay 159
The robot’s base is constructed from an 8mm steel laminated sheet, chosen for its durability and cost-effectiveness.
Measuring 20 inches by 15 inches, the base supports all components and ensures stability during movement (in Figure
Va). It houses the battery mechanism, which includes four Li-ion batteries, and a buck converter that steps down the
voltage from 16V DC to 3-5V for various components ( in Figure Vb).
Figure V. (a) Dimension of the base, (b ) Base circuitry
On top of the robot, a 2.8-inch ESP32 touch display LCD, with resolutions between 240x320 and 480x320 pixels,
enables user interaction and order placement. A webcam is also installed to monitor the robot’s position and detect
obstacles, allowing real-time visibility of any obstructions (see Figure VI).
Figure VI. Structure with dimensions
2.2 Navigation Algorithm. - The robot employs an A* path-planning algorithm to ensure optimal navigation in
dynamic environments. The algorithm processes input from ultrasonic sensors to identify obstacles and dynamically
adjust the robot’s trajectory. The A* algorithm calculates the shortest path based on cost functions that account for
distance, obstacle proximity, and time. The robot’s movement is controlled by precise motor commands derived from
these calculations.
S. Ur Rehman
Memoria Investigaciones en Ingeniería, núm. 28 (2025). pp. 154-167
https://doi.org/10.36561/ING.28.11
ISSN 2301-1092 • ISSN (en línea) 2301-1106 – Universidad de Montevideo, Uruguay 160
2.3 Software Architecture and Real-Time Obstacle Avoidance. - The IoT-based waiter robot is designed with a
robust software architecture consisting of three primary modules: the Data Acquisition Module, the Processing Unit,
and the Communication Module. The Data Acquisition Module is responsible for continuously gathering sensor data,
such as distance measurements and tray status, while the Processing Unit handles the navigation algorithm, processes
sensor inputs, and generates motor control commands. The Communication Module facilitates Wi-Fi connectivity,
enabling interaction between the robot, the kitchen interface, and the customer touchscreen. This integrated system
allows for real-time data processing and dynamic decision-making. Furthermore, the robot's obstacle avoidance system
employs ultrasonic sensors to detect potential collisions. Upon detection, the A* algorithm recalculates the robot's path
to avoid obstacles, and the motor controller adjusts the movement accordingly. Continuous monitoring ensures that
the robot can navigate efficiently and reliably, even in crowded environments.
3. Results and Discussion. - In the kitchen setup, an ESP32-controlled display allows the chef to dispatch the robot to
the customer's table to take an order. Upon arrival, a display on the robot presents menu options categorized as follows:
Appetizers (FOOD A), Desserts (FOOD B), and Grilled Items (FOOD C) as shown in Figure VII. The customer makes
their selection through the display (Figure VIII and Figure IX), which is then transmitted to the kitchen display via Wi-
Fi. After placing the order, the display shows a "Thank You" message (Figure X), and the robot returns to the kitchen.
The chef prepares the meal, places it on the robot's tray, and commands the robot to deliver it to the customer's table.
Figure VII. Chefs command the robot to take
the order
Figure VIII. Menu Display
Figure IX. Selection of Food by the customer
Figure X. After taking the order
During meal delivery, the robot follows the command from the chef to navigate to the customer's table. Once there,
the customer retrieves the meal trays, and the TCRT 5000 sensor detects the tray's removal, signaling that the meal has
been received. The ultrasonic sensor continuously scans for obstacles, with the robot stopping and sounding a buzzer
if an obstacle is detected, resuming its journey only when the path is clear. After the customer has taken their meal, the
TCRT 500 sensor confirms the absence of the tray, prompting the robot to return to its original position in the kitchen,
ready for its next task.
For the robot's movement, we selected wheels with a diameter of 4 inches (see Table III). Using smaller wheels than
this diameter would cause the robot to slip on the surface, leading to increased power consumption during rotation. On
the other hand, using larger wheels would raise the cost and result in higher power usage, making the 4-inch diameter
an optimal choice for balancing performance and efficiency.