Bahçeşehir University · Faculty of Engineering and Natural Sciences · Istanbul, May 2025
Smart Parachute System I
A functional, low-cost autonomous parachute deployment system designed to safely recover a 0.5 L water bottle payload from variable, unpredictable heights. The system uses real-time sensor fusion, accelerometer + barometric pressure, running on an ESP32-S3-Zero to detect free fall and trigger a servo-actuated release mechanism with less than 150 ms end-to-end latency.
Project Overview
Objective
Design and build an autonomous parachute deployment device that detects free fall in real time, across any launch angle or trajectory, and deploys a ripstop nylon parachute at the optimal descent point to protect a 0.5 L water bottle payload without false triggers during normal handling.
Key Features
- • 4-state FSM (Disarmed → Armed → In-Flight → Deployed)
- • Dual-sensor free-fall detection (IMU + barometer)
- • Wi-Fi manual override via SoftAP HTTP interface
- • Audible buzzer alerts across all flight states
- • <150 ms threshold-to-servo actuation latency
- • 90 % success rate over 10 drop trials at 3.5 m
Technical Stack
- • Waveshare ESP32-S3-Zero (MCU)
- • MPU-9250, 9-axis IMU (accel / gyro / mag)
- • BMP388, barometric pressure sensor
- • SG90 servo motor, release actuator
- • C/C++ firmware · Arduino ESP32 framework
- • I²C sensor bus · PWM servo control
Team
Abdulla Ahmed Mohammed
Mechanical Systems Design & Integration
Amr Nasser Benhalim
Sensor & Power Distribution Wiring
Ghiath Abdul Aziz
Communication & Control Systems
Habiba Hassan Ahmed
Data Analysis & Documentation
Advisor: Asst. Prof. Beste Bahçeci, Mechatronics Engineering
Mechanical Assembly
Component Weights
Minimising mass was critical for parachute aerodynamics. The final PLA structure achieved a total system weight of 145.57 g, printed with 1 mm wall thickness after iterative drop-test refinement.
| Part | Section | Mass |
|---|---|---|
| Right Shell | Parachute Compartment | 22.75 g |
| Left Shell | Parachute Compartment | 22.75 g |
| Deployment Pin | Release Mechanism | 2.88 g |
| Gear | Release Mechanism | 1.04 g |
| Top Plate | Release Mechanism | 9.43 g |
| Main Body | Main Body | 86.72 g |
| Total | 145.57 g | |
Electrical Subsystem
Microcontroller, ESP32-S3-Zero
Chosen for its compact form factor, built-in Wi-Fi and BLE 5.0, 4.5 MB Flash, and 2 MB PSRAM. Runs the FSM firmware in the Arduino/C++ framework. SoftAP mode exposes an HTTP interface for wireless telemetry streaming and manual override commands.
IMU, MPU-9250
9-axis sensor (accelerometer, gyroscope, magnetometer) sampling at 1 kHz over I²C. Detects free fall across all axes and throw angles by monitoring acceleration magnitude falling below the low-g threshold. Only 9.3 µA average current consumption.
Barometer, BMP388
Provides a pressure resolution of 0.18 Pa, equivalent to sub-metre altitude resolution. Used in conjunction with the IMU to confirm sustained descent before triggering deployment, eliminating false positives from brief jolts or vibration.
Servo, SG90
PWM-controlled actuator delivering 1.6–1.8 kgf·cm torque. Achieves mechanical release in 0.10–0.12 s per 60° rotation. Connected to a snap-in deployment pin that separates the left and right shells on command to release the parachute.
Power, Dual Li-ion + LM2596
Two 3.7 V / 2200 mAh rechargeable Li-ion cells in series provide 7.4 V input. An LM2596 buck converter steps this down to a stable 5 V rail. The servo supply is electrically isolated from the ESP32 logic rail to prevent brown-out resets during peak servo current draw. Average system draw under load: <120 mA.
Communication, I²C + Wi-Fi
Both the MPU-9250 and BMP388 share a common I²C bus, reducing wiring and allowing unique-address multi-device operation. Wi-Fi SoftAP broadcasts a lightweight HTTP server for real-time telemetry and authenticated manual deployment commands.
| Component | Specification | Cost |
|---|---|---|
| Waveshare ESP32-S3-Zero | Wi-Fi + BLE 5.0 · 4.5 MB Flash · 2 MB PSRAM | 320 ₺ |
| MPU-9250 IMU | 9-axis · 1 kHz ODR · 9.3 µA · I²C | 450 ₺ |
| BMP388 Barometer | 0.18 Pa resolution · sub-metre altitude · I²C | 280 ₺ |
| SG90 Servo Motor | 1.6–1.8 kgf·cm torque · 0.10–0.12 s / 60° | 50 ₺ |
| Buzzer Module | Audible status alerts during all flight phases | 15 ₺ |
| LM2596 Buck Converter | 7.4 V (2× Li-ion 3.7 V) → 5 V regulated | — |
| 2× Li-ion Battery | 3.7 V · 2200 mAh each · rechargeable | — |
| Other materials | Ripstop nylon parachute, PLA body, fasteners | 1 100 ₺ |
| System Total | 2 215 ₺ | |
Control System, Finite State Machine
The ESP32 firmware implements a 4-state FSM in C/C++. Transitions are guarded, the system can only advance to the next state after the corresponding sensor condition or user input is validated. This prevents accidental deployment during handling, launch, or turbulence.
DISARMED
Default power-on state. Actuator mechanically locked. Transitions to ARMED only via push-button input.
ARMED
Both sensors actively monitored. IMU and barometer polled at 1 kHz. System ready to detect free-fall signature.
IN-FLIGHT
Low-g event confirmed by IMU and sustained altitude drop confirmed by BMP388. Deployment imminent.
DEPLOYED
PWM signal sent to SG90 servo. Parachute released. Buzzer activated. Monitoring halts. System enters safe mode.
Click a state to highlight its transitions · Initial state: DISARMED (power-on)
Performance Metrics
Key measured values from bench-level and integrated drop testing.
< 150 ms
End-to-End Latency
threshold detected → servo actuated
1 kHz
IMU Sample Rate
MPU-9250 acceleration & orientation
0.18 Pa
Altitude Resolution
BMP388 · sub-metre accuracy
< 120 mA
Average System Draw
active sensing + processing
0.10–0.12 s
Servo Release Time
per 60° rotation under nominal load
1.8 kgf·cm
Servo Torque
SG90 release mechanism
90 %
Drop Test Success Rate
9 / 10 trials at 3.5 m height
145.57 g
Total System Mass
1 mm PLA + electronics
Live Telemetry Simulation
Simulated sensor readings based on actual project hardware specs · updates every 0.6 s
IMU Acceleration
MPU-9250 · free-fall threshold < 0.3 g
Barometric Altitude
BMP388 · 0.18 Pa resolution (~2 cm)
System Voltage
LM2596 regulated rail · nominal 5.0 V
Deploy Latency
Threshold detected → servo actuated
Sensor stream active, ESP32-S3-Zero · MPU-9250 @ 1 kHz · BMP388 · LM2596 5 V rail
Drop Test Results
10 trials conducted from a constant height of 3.5 m (first-floor building). Three deployment modes were tested: automatic free-fall detection, perturbed release (lateral push), and Wi-Fi manual override. Descent time measured by stopwatch (±0.5 s human error). Peak impact acceleration measured by the onboard MPU-9250.
| Trial | Mode | Time (s) | Peak (g) | Outcome | Notes |
|---|---|---|---|---|---|
| 1 | Auto (normal) | 1.45 | 2.1 | Soft landing | Clean deployment, stable descent |
| 2 | Auto (normal) | 1.48 | 2.0 | Soft landing | Very similar to Trial 1 |
| 3 | Auto (normal) | 1.47 | 2.2 | Soft landing | Slight canopy sway |
| 4 | Perturbed | 1.50 | 2.5 | Acceptable | Lateral oscillation, still controlled |
| 5 | Perturbed | 1.52 | 2.7 | Acceptable/harsh | Stronger swing, higher peak g |
| 6 | Perturbed | 1.49 | 2.4 | Soft landing | Good recovery despite disturbance |
| 7 | Manual Override | 1.55 | 2.3 | Soft landing | Manual deploy triggered on time |
| 8 | Manual Override | 1.60 | 3.0 | Harsh (late) | Override pressed late, shorter canopy time |
| 9 | Auto (normal) | 1.46 | 2.1 | Soft landing | Confirms repeatability |
| 10 | Perturbed | 1.51 | 2.6 | Acceptable | Moderate oscillation, no structural damage |
Descent range: 1.45 – 1.60 s · Peak acceleration range: 2.0 – 3.0 g · All electrical components intact after all 10 trials.
Summary & Conclusion
The Smart Parachute System I successfully demonstrates an autonomous, compact, low-cost parachute deployment platform. Starting from a clearly defined need, safe recovery of a 0.5 L payload from unpredictable launches, the team systematically worked through requirements analysis, component selection, mechanical CAD design, firmware development, and multi-phase testing.
The final prototype achieved a 90 % drop-test success rate from 3.5 m, with consistent deployment latency below 150 ms and peak impact accelerations between 2.0 and 3.0 g, well within the structural safety margins for both the electronics and the payload. The 1 mm PLA shell reduced total system mass to 145.57 g without sacrificing structural integrity, as confirmed by repeated drop and vibration tests.
The dual-sensor fusion approach (IMU + barometer) proved robust against false triggers during handling and normal vibration. Wi-Fi manual override via SoftAP performed reliably in all authenticated test states, with command gating ensuring that unauthorized or out-of- sequence commands were rejected. Future work (Capstone II) will focus on 3D printing cost optimisation, wider drop heights, and parachute size scaling.