1/14/15
Over the winter break I designed and built the first telemetry system prototype named Yorktown. This system used the Arduino Mega 2560, the MPL3115A2 altimeter, and the EagleTree Airspeed Sensor V2. Using the on board EEPROM I was able to store 4096 bytes of information from the sensors. This system was tested successfully several times without the aircraft. Time, altitude, temperature, and air speed were all recorded. When Yorktown was integrated into the aircraft and tested during the first test runs of the aircraft the serial clock line wire broke off of the Arduino. The meant that no telemetry information was recorded during the first test ‘fight’ of the aircraft. From this I have learned to package my telemetry system more carefully, shrink the system’s area, and use stranded wire.
The next telemetry system that I am designing will improve upon the Yorktown design by meeting the lessons learned above. This system, named Hornet, will use an Arduino Mini (about a sixth the size of the Mega), both the altimeter and air speed sensors from Yorktown, new EEPROM chips (increasing the memory from 4 kB to 32 kB), a new GPS sensor, and RF link components to begin testing the ground station portion of telemetry. The ground station will use the Arduino Mega from the Yorktown system.
I have currently been testing the GPS sensor so that I can integrate it into the Hornet system. This testing process has been slow because I have been going to the football field bleachers for testing. So far the altitude and ground speed information that I have been recording has been incorrect. The altitude is constantly reading 6533 meters (even when I go up and down the bleachers) and the ground speed ranges from 26900 m/s to 27100 m/s and I am not nearly that fast. See Figure 1 below for results.
My goals for next week are to figure out why the data being recorded from the GPS sensor is incorrect and order the remainder of the parts for the Hornet system. Mike Russo, the president of the Aero Club, also has a small drone that he has volunteering for telemetry testing. This will be something else to explore after the GPS is working correctly.
Figure 1: GPS test results from going up the football bleachers.
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