A low-cost indoor delivery robot with Arduino Uno, a servo gripper and HC-SR04 sensor, driven from a phone app over HC-05 and stopping at obstacles under 30 cm.
An academic project to design and build a low-cost delivery robot that carries orders and small objects over short distances in indoor environments such as hospitals, laboratories, offices, and educational institutions. It was carried out by a team of students with technical assistance from Techno Enjaz, and is built on an Arduino Uno, four DC motors with an L293D driver, a gripper driven by a servo motor, and an HC-SR04 distance sensor, controlled from a phone app over Bluetooth HC-05.
The robot stops automatically when an obstacle comes closer than 30 cm, and tests showed that app commands arrive with a delay of no more than 50 ms within a range of up to 8 meters indoors. The project provides a practical prototype for educational and research use that can later be extended with autonomous navigation and computer vision.
| Item | Details |
|---|---|
| Project type | Prototype of a remotely controlled indoor delivery robot |
| Field | Mobile robotics, embedded systems, wireless communication |
| Project status | Assembled prototype tested in practice indoors |
| Techno Enjaz role | Technical support and assistance to the students during project development |
| Core technologies | Arduino Uno (ATmega328P), Arduino IDE and C++, L293D, TT motors, servo motor, HC-05, HC-SR04, 18650 batteries with BMS |
| Outputs | Four-wheel robot with an order compartment, gripper for picking up orders, phone control app, automatic stop at obstacles |
Hospitals, laboratories, warehouses, and educational institutions frequently need to move small objects and materials over short distances. Although commercial robotic systems exist for this, most are expensive and complex, which limits their use in educational projects and small applications with limited budgets.
The project set out to build a mobile robot that picks up and carries objects while reducing human involvement in routine transport, using available, low-cost electronic components while keeping acceptable performance and making it easy to operate, maintain, and extend.
The project was carried out academically by the students, with technical assistance and support from Techno Enjaz during development. It is presented among the office's work as an example of its support for low-cost mobile robotics and embedded-systems projects.
The program is split into independent functions for each task, which makes it easy to modify or extend without rebuilding it entirely.
The robot has a lower base carrying the four-wheel drive system and an upright body containing a dedicated compartment for orders, with a front opening that makes loading and unloading easy. The sensor is mounted at the front of the base facing the direction of travel, the components are distributed evenly to reduce vibration, and the outer shell is simple and enclosed to protect the components while keeping them accessible for maintenance.
| Component | Role in the system |
|---|---|
| Arduino Uno (ATmega328P) | Main controller: receives commands and manages all modules |
| Four TT gear motors | Drive the four wheels; the two motors on each side are wired in parallel |
| L293D driver | Controls the direction and speed of the right and left motor pairs |
| Servo motor | Opens and closes the gripper to pick up orders and release them at the drop-off point |
| HC-SR04 ultrasonic sensor | Measures the distance ahead and detects obstacles |
| HC-05 Bluetooth module | Receives app commands wirelessly |
| Three 18650 lithium-ion cells | Wired in series to give about 11.1 V for the board and motors |
| BMS protection circuit | Protects against overcharge, deep discharge, overcurrent, and short circuits |
| Module | Pins used |
|---|---|
| L293D (right motors) | D8 and D9 for direction, D10 for speed (PWM) |
| L293D (left motors) | D11 and D12 for direction, D13 for speed |
| Servo motor | D3 for the gripper angle signal |
| HC-SR04 | D4 to send the pulse (TRIG), D5 to receive the echo (ECHO) |
| HC-05 | D6 and D7 via SoftwareSerial to avoid conflicts with D0 and D1 |
| Power | Battery to the Arduino's Vin pin and to the L293D's Vcc2, with a common ground for all components |
The motors are powered directly from the battery through the L293D, while the controller logic, servo, sensor, and Bluetooth module run on 5 V from the board, isolating the control circuit from the motors' high loads.
The team developed a dedicated smartphone app that connects to the HC-05, with a simple interface containing the basic motion buttons and the gripper open/close buttons, each in a distinct color to make them easy to recognize during operation. The interface design allows adding buttons later for speed control or advanced operating modes.
The practical tests covered the wireless link, movement in different directions, the distance sensor's response, and gripper control:
| Test | Documented result |
|---|---|
| HC-05 link | The connection worked and the robot responded to commands directly with no noticeable delay |
| App response time | No more than 50 ms within a range of up to 8 meters indoors |
| Movement | The robot moved steadily in all required directions indoors |
| HC-SR04 sensor | Detected obstacles and stopped the robot when closer than 30 cm |
| Gripper | Stable performance opening and closing and handling orders |
The book does not state the maximum payload in grams, travel speed, battery runtime, or the number of test repetitions.
According to the outlook in the project:
If you are working on a mobile robot or autonomous vehicle and need technical help developing the idea or building a prototype, you can contact the Techno Enjaz office to discuss your project's requirements and the appropriate scope of support.
It is a low-cost prototype for carrying orders and small objects inside indoor environments such as hospitals, laboratories and offices, built by a team of students with technical assistance from Techno Enjaz. It has a four-wheel base, an upright body with an order compartment and a servo-driven gripper, and is controlled from a phone app over Bluetooth.
The phone app sends single-letter commands over the HC-05 module (F, B, R, L and S for motion and stop; G and O to close and open the gripper), and the Arduino Uno drives the motors through the L293D or moves the servo. While moving, the HC-SR04 sensor measures distance continuously, and if it drops below 30 cm the controller stops all motors and waits for a new command.
The robot uses an Arduino Uno with the ATmega328P, four TT gear motors driven by an L293D, a servo for the gripper, an HC-SR04 sensor and an HC-05 module. Power comes from three 18650 lithium-ion cells in series at about 11.1 V with a BMS protection circuit, and it was programmed in C++ in the Arduino IDE.
The HC-05 link worked, and app command delay was at most 50 ms within a range of up to 8 meters indoors. The robot moved steadily in all directions, stopped at obstacles closer than 30 cm, and the gripper opened and closed reliably.
The robot works indoors on flat floors and carries only light objects; it is steered manually from the phone without autonomous navigation or computer vision and relies on a single front sensor. The book does not document maximum payload or battery runtime, and proposes autonomous navigation, Wi-Fi, a camera and automatic return to charge as future work.
Reach out to Techno Enjaz engineering team to discuss technical feasibility, prototype hardware, and development scope.
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