SYS_MODULE // 06

Fire Suppressant Drone

PCB_DESIGN UAV_SYS KiCad

> Exec_Summary

For the main project in my Introduction to Engineering Design course, my team conceptualized a fleet of inexpensive drones capable of supplying a continuous stream of fire suppressant to a region. My primary task was designing the electronics subsystem: handling user/sensor input, motor control, fire suppressant deployment, and power distribution.

> Sensor_Array_&_Telemetry

To position the drone over the fire, the system utilized an MQ gas sensor and an 8x8 infrared sensor running over I2C to "seek" heat and smoke. Telemetry was reported back to home base via a 2.4GHz transceiver.

Location and orientation were managed by a GPS module and an MPU-6050 6-axis accelerometer/gyroscope. Because the MPU-6050 lacked a built-in motion processor, I implemented a FIFO (First-In, First-Out) scheme triggered by hardware interrupts. This proved to be a processing bottleneck, occasionally causing the Arduino to struggle keeping up with the gyroscope data and other flight routines.

> Power_&_PCB_Design

I designed a custom PCB in KiCad. Power was supplied via a 12V XT60 connector and distributed to four motor Electronic Speed Controllers (ESCs). While the motors were rated for 20-30A peaks, I designed the board using 1oz copper to handle ~10A per motor to keep prototyping costs low. I implemented individual decoupling capacitors for each motor to filter noise caused by unpredictable wind-adjustment loads.

A linear voltage regulator provided a clean 5V supply for the logic components. To ensure signal integrity, I deliberately routed the high-current motor traces as far from the data traces as possible to prevent crosstalk.

> Hardware_Debugging

The initial PCB revision had several critical routing errors: reversed power pins on the radio transceiver, an incorrect gyroscope pinout, and disconnected ESC data pins. By soldering jumper wires to the back of the board, I successfully patched the ESC connections, allowing us to successfully demonstrate the motors in a tethered flight configuration.