Mini_ESP_Drone

The Mini PCB drone is designed with a meticulous selection of components to achieve a compact, efficient, and high-performance system. The hardware design revolves around integrating critical components onto a 10x10 cm PCB, ensuring that the drone remains lightweight while maintaining robust functionality.

Key Components

   1. ESP32-S3 Microcontroller:

The ESP32-S3 is the central processing unit, providing computational power and On-The-Go (OTG) support. It manages all onboard operations, including image processing, communication, and motor control. Its small footprint and high performance make it ideal for integration into the drone’s compact design.

   2. OV2640 Camera Module:

The OV2640 camera was chosen for its ability to capture high-resolution images, which are critical for the drone's imaging functionality. The camera's interface with the ESP32-S3 is optimized to ensure fast data transfer and minimal latency.

   3. 8520 Coreless Motors:

These coreless motors are essential for the drone’s propulsion. They are selected for their high thrust-to-weight ratio, which allows the drone to maintain stable flight even with the added weight of onboard electronics. Their small size and efficiency are crucial for fitting within the drone’s compact frame.

   4. Gyro Sensor (MPU6050):

The gyro sensor is integrated to provide orientation and stability feedback, essential for maintaining controlled flight. It helps in stabilizing the drone, especially in dynamic flight conditions.

   5. SD Card Reader:

An SD card reader is included for local data storage using SD-MMC technology, allowing the drone to save captured images and sensor data. This feature is crucial for operations where real-time data transmission is limited or when data needs to be logged for later analysis.

   6. SI2302A-TP MOSFET

The SI2302A-TP MOSFET is utilized for precise motor control within the drone. This dual N-channel MOSFET is chosen for its low threshold voltage and high efficiency, allowing for effective switching of the coreless motors. Its compact SOT-23 package is ideal for the drone's limited PCB space, ensuring reliable motor performance while minimizing power loss.

Power Regulation System

The power regulation system is a critical aspect of the drone's design, ensuring that all components receive stable and appropriate power levels. The following voltage regulators are employed:

   1. XC6220B331PR-G (for Motors and SoC):

This voltage regulator provides a stable 3.3V output, which is essential for powering the ESP32-S3 microcontroller and the 8520 coreless motors. Its high efficiency and low dropout characteristics make it ideal for battery-powered applications where energy conservation is crucial.

   2. ME6211C28M5G-N1 (for Camera):

The ME6211C28M5G-N1 provides a regulated 2.8V supply specifically for the OV2640 camera module. This ensures the camera operates within its specified voltage range, maintaining image capture quality and reliability.

   3. ME6211C15M5G-N2 (for Camera):

Another regulator, the ME6211C15M5G-N2, supplies a stable 1.5V to the camera’s internal circuits. This dual-voltage supply is necessary to meet the camera’s power requirements, ensuring proper operation and minimizing power consumption.

Battery Charging and Protection System

The battery system is a critical component of the drone, providing the necessary power while ensuring safety and longevity. The design includes a charging circuit and protection mechanisms to prevent overcharging, deep discharge, and short circuits.

   1. TP4056 Battery Charger:

The TP4056 is a linear lithium-ion battery charging module with a constant current/constant voltage (CC/CV) charging scheme. It safely charges the drone’s LiPo battery, providing the necessary charge regulation to extend battery life and prevent overheating.

   2. DW01A Protection Chip:

The DW01A protection chip is used in conjunction with the TP4056 to monitor the battery for overcharge, over-discharge, and overcurrent conditions. This chip provides essential protection, ensuring that the battery operates within safe limits.

   3. FS8205 Dual MOSFET

The FS8205 is a dual N-channel MOSFET used in the battery protection circuit. It works with the DW01A chip to disconnect the battery in case of a fault, protecting both the battery and the drone’s electronics from damage.

PCB Design Considerations

The PCB layout is optimized for space efficiency and durability. The use of surface-mount technology (SMT) allows for a compact design while maintaining the necessary strength and reliability. Key considerations include:

Component Placement:
Critical components like the ESP32-S3, OV2640 camera, and SI2302A-TP MOSFET are strategically placed to minimize signal interference and ensure efficient power distribution. The placement of the motors and camera is carefully managed to maintain the drone’s balance and provide an unobstructed field of view for imaging.

Power Distribution:
Power traces are designed with appropriate widths to handle the current demands of the motors and microcontroller without significant voltage drops. Decoupling capacitors are strategically placed near power pins to filter out noise and stabilize voltage levels.

Thermal Management:
Components that generate heat, such as voltage regulators and MOSFETs, are positioned to allow for adequate heat dissipation. Thermal vias and heat sinks may be employed to manage heat buildup, ensuring long-term reliability and preventing thermal-related failures.

Signal Integrity:
High-speed signals, especially those related to the camera and microcontroller communication, are routed with minimal interference. Ground planes and proper shielding techniques are used to maintain signal integrity and reduce electromagnetic interference (EMI).

Resources

• https://dl.espressif.com/dl/schematics/ESP-LyraP-CAM_V1.0_SCH_20200302.pdf
• https://dl.espressif.com/dl/schematics/SCH_ESP32-S3-EYE-MB_20211201_V2.2.pdf
• https://taunoerik.art/wp-content/uploads/2023/05/esp32s3_pinout.png
• http://wiki.fluidnc.com/en/hardware/ESP32-S3_Pin_Reference