Budapest University of Technology and Economics Department of Aircraft and Ships has an UAV (unmanned aerial vehicle) project, utilizing a Paparazzi autopilot module. The aircraft has a radio downlink to the ground computer during flight, but the link is limited due to frequency restrictions. To conduct researches and measurements the data of the aircraft’s sensors has to be logged onboard. The task was to design that data logger module’s hardware and software, manufacture the necessary components and program the microcontroller.
After consulting with the leading instructor of the UAV project Dr. Balázs Gáti, I have studied the Paparazzi project and the TWOG board, which is the central controller board of the aircraft. For the communication there is an SPI port available on the TWOG board, and the port supplies the module with 3.3 V power. After considering the possibilities I have decided to use an SD memory card for the data logging, chosen the AT90USB647 microcontroller and included a mini-USB port, which makes it possible the read the data from the card without removing it from the module. After creating the high level design I have chosen the required parts and designed and built the PCB. After designing the software I have chosen the necessary hardware modules to use. To handle the file system the logger uses the FatFs module, the USB is handled by the AVR276 library of Atmel. I have become familiar with these modules and integrated them into the software.