Telemetry on a kite or "papagayo" connected to the internet of things (IoT). A kite is a flying device used for entertainment that consists of a surface of paper, cloth, or other lightweight material mounted on a solid cane frame and attached to a thread at the bottom.

The idea is mount sensors to the frame for measure environmental conditions at a certain flight altitude. Then store data with a data-logger prototype and subsequent numerical analysis.

"Papagayo" is the same of kite in Spanish language.

Project Overview

The "Papagayo-IoT Sky-Logger" is a lightweight, ruggedized telemetry system designed for atmospheric "Citizen Science." By mounting a suite of sensors onto a high-altitude kite (or Papagayo), the project captures environmental variables like temperature and pressure at heights inaccessible to ground-based stations. Utilizing an Arduino Uno and a specialized I2C Real-Time Clock, the system timestamps and saves data to non-volatile memory in real-time. This allows for a "Post-Flight" data analysis workflow, where the flight path's thermal gradients can be mapped and visualized on a PC.

Goals

Measure environmental variables on a flying thing (kite or "papagayo") using Internet of Things (IoT) technology. e.g temperature, altitude, humidity, etc.
Build a hardware and software prototype.
Analyze the data later.

Technical Deep-Dive

One-Wire Bus Architecture (DS18B20):
- The Single-Wire Master: The DS18B20 temperature sensor is unique because it uses the Maxim One-Wire protocol. This allows the Arduino to communicate with multiple sensors using just one digital pin.
- Pull-up Resistor Logic: A 4.7K Ohm resistor is placed between the data line and VCC. This provides the "Passive High" state required for the One-Wire signaling, ensuring data integrity across the long jumper wires needed to place the sensor at the edge of the kite's frame.
I2C Multi-Device Management (DS1307 Module):
- The project utilizes a dual-function RTC module. On the I2C bus (Pins A4/A5), the Arduino addresses the DS1307 (0x68) for precise time tracking and the 24C32 EEPROM (0x50) for data storage.
Non-Volatile Logging (EEPROM):
- Internal Arduino Uno memory is limited (1KB). By using the 24C32 EEPROM, the Papagayo system can store up to 32kbits (4000 bytes) of sensor data.
- The MyData Struct: To optimize memory usage, the firmware uses a C++ struct that packs the timestamp (hour/min/sec) and the temperature value into a single binary block, maximizing the number of flight records possible before needing a data dump.
Event-Driven Temporal Loops:
- The "Elegant Loop" in the firmware doesn't log data at maximum speed (which would fill the memory in seconds). Instead, it polls the DS1307 for a "Match" against a pre-set time interval, ensuring that readings are captured at consistent 5 or 10-second cycles for accurate graphing.

Documentation Code

First, add some library for I2C comm in Arduino. The module DS1307 has a simple I2C interface that takes up two addresses. The DS1307 RTC chip’s fixed I2C address is 0x68, and the 24C32 EEPROM’s fixed I2C address is 0x50.

Second, setup RTC and set time alarm for kite flying.

Third, see the elegant loop when running and wait for alarm events.

Fourth, read temperature sensor in an event time associate.

Fifth, write data in an internal memory EEPROM module.

And finally see MyData is a data structure to manage environmental variables.

Diagram

Arduino pines A5 and A4 to RTC DS1307 . They are also referred to as A5 (SCL) and A4 (SDA).

Solder the DS18B20 according to the polarity shown on the documentation section. After installing the DS18B20, you will be able to obtain temperature readings from the DS pin. You may also require a 4.7K resistor between VCC and DS.

Engineering & Aerodynamics

The "Pringles" Housing Solution: High-altitude flight presents challenges in vibration and wind resistance. The use of a 40g Pringles jar serves as a lightweight, cylindrical fairing. It protects the breadboard and Arduino from turbulent air while maintaining a low drag coefficient, which is essential to keep the kite stable.
Power Management: Flying for extended periods requires a reliable energy source. The 9V battery provides ample overhead for the Arduino's 5V regulator, while the CR2032 coin cell ensures the RTC never loses its synchronization, even if the main flight battery becomes detached during a rough landing.
Field Deployment: The project emphasizes a "Switch-to-Fly" workflow. A physical toggle switch acts as the "Record" trigger, allowing the user to ground-test the system before committing the kite to the troposphere.
Numerical Analysis: Data retrieved from the EEPROM is typically exported to a CSV format. This allows students to calculate the Lapse Rate (temperature change per unit of altitude), bridging the gap between hobbyist electronics and professional meteorology.

Results