SkyGuard

UAV MISSION V3.0 ESP32 CHASSIS TESTBED

Autonomous Delivery Drone Operations · Physical Carrier & L298N Drive Integration

SIM800L: CSQ —

UAV-ALPHA (SG-01)

Payload Carrier Chassis · Quad-Prop Vector Sim

EN ROUTE

Mission Vector Progress —

Hub: Central Depot ETA: — Target: Zone A-3

Battery Power

— V —

Cutoff threshold: 3.50 V

GSM SIM800L

CSQ — — dBm

GPRS 2G Attached

NEO-6M GPS Fix

— Sats 3D Fix

HDOP: —

Obstacle Radar

— m

Awaiting sensor

Ground Speed

— km/h

— m/s

Flight Altitude

— m AGL

Barometric AGL

GPS Telemetry Coordinates no packets

LAT: —, LON: —

Heading: — Distance Flown: — m

Payload

EMPTY

No package aboard.

L298N Drive Carrier

L: — · R: —

PACKETS: 0

HAZARDS: 0

BREACHES: 0

UAV Tactical Sector

Zone Alpha · Flight Corridor #4

Vehicle Target DEPOT → DEST-01

Signal CSQ CSQ — / 31

Mission Planner

Geofence 4 vertices

Warehouse / Hub

Delivery Destination

Map Overlay Legend

Live Drone / Carrier Position

Telemetry Breadcrumb Trail

Active Geofence Perimeter

Ultrasonic Obstacle Event

Delivery Drop Target

SkyGuard Real-Time Event & GSM Alert Console

Stream: GPRS / WebSocket Active

Ground Carrier Chassis & Motor Teleoperation

L298N DUAL H-BRIDGE CONTROL

Direct hardware control and diagnostics for the robot chassis acting as the physical drone payload delivery testbed.

Left Motor Bank (Channel A)

Pins: ENA=25, IN1=26, IN2=27

FORWARD

PWM Throttle (LEDC Channel 0) — / 255

IN1 (GPIO 26) —

IN2 (GPIO 27) —

ENA (GPIO 25) —

Manual Teleop Cockpit

Keyboard shortcuts: [W] [A] [S] [D] or Space to Brake

High-Speed Throttle 250 PWM (High Speed)

Right Motor Bank (Channel B)

Pins: ENB=13, IN3=14, IN4=12

FORWARD

PWM Throttle (LEDC Channel 1) — / 255

IN3 (GPIO 14) —

IN4 (GPIO 12) —

ENB (GPIO 13) —

Why a Ground Chassis Payload Carrier?

In many academic, engineering, and rapid-prototyping environments, flying an autonomous multirotor delivery drone outdoors or indoors presents significant aviation safety hazards, battery endurance limitations, and airspace regulations. By housing the exact same UAV payload stack (ESP32, NEO-6M GPS, SIM800L GSM, HC-SR04 ultrasonic obstacle radar, battery telemetry) onto a wheeled robot chassis driven by an L298N motor driver, the ground rover serves as a 1:1 physical surrogate and payload carrier. The SkyGuard Mission Control UI visualizes the vehicle through a high-tech drone operations interface, tracking vectors, geofence compliance, and delivery milestones with complete safety.

Real-Time Telemetry Analytics & Log Studio

Continuous streaming metrics from SG-01 over SIM800L GPRS cellular link.

Battery Voltage Discharge (V)

Cutoff: 3.50 V

GSM Signal Strength (CSQ 0-31)

Min: 10 CSQ

Ground Velocity (km/h)

Cruise: 15 km/h

Ultrasonic Proximity (m)

Hazard: <1.5 m

Raw GPRS Telemetry Packet Stream

Updated every 5 seconds

Time	Latitude	Longitude	Speed	Alt	Sats	HDOP	Dist (m)	VBat	CSQ	Mode	Alert

Complete Hardware Wiring, Pinout & Data Flow

Schematic lookup for ESP32, L298N Dual Motor Driver, NEO-6M GPS, SIM800L GSM, and HC-SR04 sensors.

ESP32 Core Microcontroller

Dual-Core 240 MHz Xtensa LX6. Manages UART2 for NEO-6M GPS, UART1 for SIM800L AT commands, LEDC PWM channels for L298N, and runs the non-blocking state machine.

L298N Dual H-Bridge Driver

Drives 2 or 4 DC gear motors for skid-steering ground carrier movement. Up to 2A per channel. Connected to ESP32 GPIOs 25, 26, 27, 14, 12, 13. Common ground required!

u-blox NEO-6M GPS

High-sensitivity GPS receiver (9600 baud, 1Hz NMEA stream). Provides latitude, longitude, speed, heading, and HDOP precision directly into TinyGPS++.

SIM800L Quad-Band GPRS

Sends telemetry packets via HTTP POST to the SkyGuard server and dispatches emergency SMS alerts. Requires 3.7V-4.2V (2A peak) with a 1000uF capacitor!

Pin Connection Matrix (ESP32 DevKit V1)

Subsystem Module	Module Pin	ESP32 Pin (GPIO)	Function / Signal	Critical Notes
L298N Motor Driver	ENA (Left PWM)	GPIO 25	LEDC PWM Channel 0	Remove jumper on L298N ENA pin
L298N Motor Driver	IN1 (Left Forward)	GPIO 26	Digital Output	Motor A Direction 1
L298N Motor Driver	IN2 (Left Reverse)	GPIO 27	Digital Output	Motor A Direction 2
L298N Motor Driver	IN3 (Right Forward)	GPIO 14	Digital Output	Motor B Direction 1
L298N Motor Driver	IN4 (Right Reverse)	GPIO 12	Digital Output	Motor B Direction 2
L298N Motor Driver	ENB (Right PWM)	GPIO 13	LEDC PWM Channel 1	Remove jumper on L298N ENB pin
NEO-6M GPS	TX	GPIO 16 (RX2)	HardwareSerial 2 RX	Receives NMEA sentences at 9600 baud
NEO-6M GPS	RX	GPIO 17 (TX2)	HardwareSerial 2 TX	Commands to GPS (optional)
SIM800L GSM	TXD	GPIO 18 (RX1)	HardwareSerial 1 RX	AT responses & HTTP download
SIM800L GSM	RXD	GPIO 19 (TX1)	HardwareSerial 1 TX	AT commands dispatch
HC-SR04 Ultrasonic	TRIG	GPIO 4	10µs Trigger Pulse	Digital Out
HC-SR04 Ultrasonic	ECHO	GPIO 5	Echo Pulse Width	Use 1k/2k divider if sensor is 5V
Battery Monitor	Resistor Divider	GPIO 34	ADC1 Channel 6	100k + 100k (2:1 divider)
Power Rails	GND (Ground)	GND	Common Ground	MANDATORY: Tie all GNDs together!

Critical Power & Surge Advisory (SIM800L & L298N)

1. SIM800L Power Spike: The SIM800L requires 3.7V - 4.2V and draws up to 2.0 Amps during cellular transmission bursts. Do NOT power the SIM800L from the ESP32 3.3V pin, as this will trigger instant ESP32 brownout reboots. Use an external buck converter (LM2596) or 1S LiPo battery with a 1000µF 16V low-ESR electrolytic capacitor across SIM800L VCC and GND.
2. Common Ground: Connect the Ground (GND) of the ESP32, L298N, SIM800L, and batteries together to establish a common logic reference.
3. Motor Power Isolation: Power the L298N motors with a separate 7.4V - 12V battery pack.