PCB Drone
Ethan Long and Ronan Loberg
Embedded Files
We wanted to make a battery-powered PCB quadcopter is remotely controlled on the Blynk app. Acceleration and angular velocity measurements are made by an LSM6DSO breakout board and displayed on the app. The drone is powered by a single cell battery, and the motors are driven by the ESP32 through H-bridge drivers.
ESP32 Schematic
ESP32 Schematic
Our ESP32 wiring incorporates reset and boot switches to enable easy code uploading. The ESP32-S2 was chosen due to its ability to directly wire a USB port to the chip without the need of a UART IC. A LED is included to visually verify the ESP32 is receiving proper voltage.
Schematic for one of the four brushless DC motors. The wiring for the other motors is similar but the H-bridges are wired to different pins on the ESP32.
Motor Schematic
Motor Schematic
The drone's motion is controlled by four brushed DC motors. Brushed motors controlled by an H-bridge allow for easy integration onto a PCB, unlike brushless DC motors. This particular H-bridge allows for directional and speed control of the motor via PWM signals from the ESP32.
Battery Regulator
Battery Regulator
The drone is powered by a 3.7V LiPo battery. Due to the fluctuations in battery voltage over its use a voltage regulator ensures a consistent 3.3V to the ESP32. To maximize the power of the motors, the voltage of the battery is wired to power the four motors since at full charge the battery will have a voltage of around 4.2V. The motors were chosen so that they would stay powered despite the battery voltage dropping over its use time.
IMU schematic
IMU schematic
To collect flight data an IMU is attached to measure acceleration and angular velocity in all three axes. To read the data on the ESP32 we are using the I2C protocol through the SCL and SDA pins on the ESP32.
PCB Layout
PCB Layout
The board edge was created in SolidWorks and imported to capture the drone shape. The LiPo battery and IMU holder are 3D printed attaching to the mounting holes on the bottom of the board (light blue regions). The board edge geometry pushes the center of mass towards the center of the drone; the battery can then be positioned to adjust the center of mass to provide a more stable flight.
H-bridge layout issues have forced us to have to reorder boards (which were delayed 1.5 weeks in shipping)
Motors are press-fit into mounting holes, and have 3D printed propellers
Leads from the battery and IMU wrap around the front of the board, and utilize through holes in the front side.
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