Integrated System Build & Test
Table of Contents
Project RecapThe High Altitude Balloon Instrumentation Platform (HABIP) is a multi-functional system that allows users to collect and analyze data from near-space experiments. The device records internal data, and also telemeters data that has been gathered from an array of sensors to a ground communications center. The goal of this project is to create the aforementioned array in a configuration that is lightweight, cheap to manufacture, and highly reliable. The final product will undergo a mission lasting for several hours in harsh conditions, and will parachute back to Earth from an altitude of over 100,000 feet to be recovered and analyzed. This project seeks to improve upon the progress of two former MSD groups: P17104 and P17105, and is intended to be a design which can be further improved in the future.
Team Vision for Integrated System Build & Test PhaseSummarize:
- During this phase, the plan was to fully integrate all subsystems with one another
- The decision was made during this phase to jettison most of the COMMS functionality from the project
- Many subsystems were integrated, but continued problems with the DTV meant that testing had to continue, acting as a barrier to progress
The individual subsystems were assembled as modules for the purpose of testing concurrently. After the main board was populated with components, all connections and GPIOs were tested for proper function. The reaction wheel was tested as a standalone system, with all necessary components attached to the chassis and suspended freely. The parameters of the reaction wheel motor controller were calibrated to fit the bare-bones platform weight, and rotational motion was imparted manually to the chassis, which was quickly corrected by a responsive motion in the wheel. Digital video testing was among the most extensive, with experimentation done using antennae made in house as well as off-the-shelf products. The ground station antenna was installed and configured to allow for reception of data from the HABIP. Testing of the data acquisition sensors was comparatively simple, as the boards were previously configured for this equipment, though great efforts were taken to ensure the accuracy of the information as it was interpreted. As pressure data is the most accurate means of determining altitude available, these sensors were carefully calibrated so that system functions occur as expected as the platform gains altitude. The pressure sensors were tested by walking from the Gleason circle bus stop to the fourth floor balcony in Gleason Hall. This represented a few hundred foot elevation change, which was successfully recorded in the pressure sensor. The temperature sensors were tested going from inside the lab (about 70°F) to outside. This test was performed during the winter, and the 40°F temperature change was successfully recorded by the temperature sensor. The IMU was tested by moving the PCB around (angular rotation as well as acceleration) and the data was recorded and verified.
Testing for the DTV was done using a variety of different antennas and configurations. The antennas that we were using were not designed for the frequency that was necessary, and therefor many different configurations were used. The DTV was successfully transmitted and received from inside the lab, although this was believed to be received through leakage to the digital receiver. Testing of the DTV outside was never completely successful. Using a co-linear antenna (which ended up breaking later in testing) video was successfully received from the bottom of H-Lot. There was a lot of Transmit Power in this configuration and so it was able to be successfully received. Once the platform was moved further away than this spot (or if a different antenna without as much gain was used) the video was not able to be received when outside. The problem was believed to be with the receive configuration. It was seen that the pre-amp on the ground station made no difference to the signal level when it was toggled. Due to time constraints this was never able to be fully investigated.
- DTV tests will be completed over varying distances and under different conditions to determine the optimal setup