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DemoSat /
FieldSatFieldSat mission descriptionOn-board sensors record orientation and vibration information during flight. Testing of instrumentation prototypes for use in later missions. OverviewOur implementation of the FieldSat subsystem uses a microcontroller and electronic sensors to record various data about the flight. These data will be recorded without interpretation onto two Secure Digital cards attached to the microcontroller. We will make custom printed circuit boards to hold the sensors and use cables to connect them to the microcontroller. The microcontroller will be running a simple program to coordinate these activities (see FieldSat software). The microcontroller will have the additional functions of controlling the SolarSat's deployment latch and controlling the heater. Subsystem statusA prototype of the subsystem has been built and tested. Programming is finished enough to launch. For detailed programming status see FieldSat software. (Heating information moved to Heater.) Quantities measuredThere are 12 quantities that our FieldSat will measure. These are
PartsThis is a list of parts we're going to use for the FieldSat. On-handWe have three ADXRS300 angular rate sensors (gyroscopes). Our SD card interfaces are two of these. We decided on using the ATmega32 microcontroller from Atmel. We're going to use the ATmega control board from Futurlec to do development. This board is small enough that it can be used in the final payload as well. We will use two external AD7859 analog-to-digital converters. We will use two 5-g ADXL320 and two 18-g ADXL321 accelerometers. We will make an altimeter out of the MPX2100A pressure sensor. David's message describing this sensor is here. Two AD22100 temperature sensors. One 128 MB SD card. DecidedOne more 128 MB SD card. UndecidedWe need the parts for the solar cell deployment latch. DimensionsWe will need at most 8" by 8" by 2" for the microcontroller and sensors, plus two other areas of about 2" by 2" by 0.5" for the Secure Digital cards. TestingI accidentally left the FieldSat on one night for almost 12 hours, pegged at a 100 Hz sample rate. In 11:43:40.521, 134617632 bytes (128.38 MB) were written to the SD card. So at this sample rate, for three hours, it will use 134617600 / (11 * 3600 + 43 * 60 + 40.521) * 3 * 3600 = 34435152 bytes (33 MB). So I recommend getting 128 MB cards, to allow for the sample rate to be greater or get a recording time of more than 3 hours. Budget
Mass budget
Team members
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