Building a custom rocket altimeter is a challenging yet rewarding project for aerospace enthusiasts. Often, commercial altimeters are either too expensive or out of stock. This project provides a cost-effective, DIY solution that weighs only 24g (including battery) and accurately tracks a rocket's peak altitude using air pressure differentials.

Flight Performance Monitoring Overview

The Rocket Altimeter project is a specialized application of Barometric Data Processing. In the high-velocity environment of a model rocket launch, the system must capture the precise moment of "Apogee"—the highest point of flight—before the rocket begins its descent. This project highlights the importance of Weight-to-Power Optimization and Data Peak Detection, turning an Arduino Nano into a dedicated piece of avionics.

Hardware Infrastructure & The Flight Tier

• Arduino Nano R3: Serves as the high-speed "Flight Computer." Its small form factor and 5V operating range make it ideal for fitting inside the narrow fuselage of a model rocket.
• BMP280 Barometric Sensor: The primary detector. It measures ambient air pressure with a precision of ±1 meter. As the rocket climbs, the air pressure drops; the Arduino uses a logarithmic formula to convert this pressure drop into a height measurement.
• Graphic OLED Display: Provides an instant readout of the flight data (in both meters and feet) once the rocket is recovered. This eliminates the need for a field laptop to verify launch success.
• 3.7V 100mAh LiPo Battery: Provides more than 4 hours of standby time while keeping the total weight at a minimal 24g, ensuring the rocket's center of mass remains stable.

Technological Logic and Peak Acquisition

The software is designed to handle the dynamic nature of a launch:

1. The Pre-Flight Calibration: Upon reset, the Arduino samples the ground-level air pressure to set a baseline (0 meters).
2. The Sampling Loop: During flight, the Arduino reads the BMP280 at high frequency. It stores two primary variables: maxAltitude and currentAltitude.
3. Apogee Logic: If currentAltitude is greater than maxAltitude, the system updates the peak. The difference between the Max and Min readings ensures the result is accurate even if the sensor drifted slightly during the wait on the launch pad.
4. Safety & Status: The system features a blinking LED for visual confirmation that it is armed. A buzzer sounds after a set duration (e.g., 3 minutes) to help find the rocket if it lands in tall grass or trees.

Why This Project is Important

Mastering rocket avionics is a major milestone for hobbyists. It teaches you how to deal with Thermal Drift, High-G Forces, and Energy Efficiency. It proves that you can build professional-grade research tools for a fraction of the cost of retail units. Once the basic altitude tracking is perfected, you can expansion this project into an Active Deployment System that uses the apogee trigger to fire an electronic match and deploy the recovery parachute automatically.