Firstly, I would like to thank mbed for their sponsorship of my project by donating a mbed LPC1768. Also, thanks to the authors of all the libraries I used like MODSERIAL, MODGPS, MAX3100, SDFileSystem, FatFileSystem, and BufSerialRPC.

This project was undertaken for my Senior project in Mechanical Engineering in the Spring of 2011. The objective of the project was to autonomously guide a payload down from 100k ft. that was carried to that altitude by a weather balloon. The system was to control a parafoil by means of two winch servos. The project was never fully developed because of time constraints and the difficulty in testing the system. The mbed did in fact fly onboard a plane that was used to test the avionics system. Another mbed was used to test the parafoil deployment system, where the payload was thrown from the plane and deployed the parafoil with an actuator. All of the electronics and software performed their tasks during testing. Testing was concluded by malfunctions in the parafoil deployment, and resulting crashes.

Here are some flight test videos. The full avionics board was never thrown from the plane because of the the parafoil issues. The tests show the parafoil deployment using an mbed as a timer that actuated the actuator and released the parafoil. RAISE YOUR HAND IF YOU'VE EVER THROWN AN MBED FROM A PLANE AND YOU STILL USE IT!!!!

Here are some pics of the finished mbed controlled avionics board.

Main Components Mbed LPC1768

Coolcomponents mbed workshop development board (version 2a)

CHR-UM6 IMU/AHRS

GM862-GPS Cellular GSM & GPS module

DNT900 1Watt RF Modem

HiTEC HS-785HB Winch Servos (2)

Firgelli PQ12 Linear Actuator

Hyperion 7.4v 2600mAh LiPo batteries (2)

Hyperion 7.4v 16000mAh Lipo batteries (1)

The base (ground) station consisted of another DNT900 RF modem and a laptop running LabView. The system was fully functional in that GPS and IMU telemetry was sent to the base station and was viewed in LabView. The system was also functional with controlling the winch servos and deployment actuator from the LabView vi over the RF modem.

The avionics board also was able to record all telemetry on the uSD card.

Here are the MATLAB plots from the uSD card data that was recorded while the full avionics board was on the plane during a test drop.

The next incarnation of this project is to adapt it to a UAV which are much easier to test than an unpowered parafoil. An airspeed sensor will also be added.

Here is a general layout.