C&DH Electrical Layout
CPU Schematic:
The Command and Data Handling subsystem consists of four basic elements:
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One which processes the 8 digital signals from the sun sensor and through
a series of CD4066
quad switches returns a single resistance (R1) which is seen by the 555
timer.
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The CPU also receives the voltage across the temperature sensor, performs
a series of comparisons to reference voltages, and returns a three bit
number corresponding to hot (100), ambient (010), or cold (001). This three
bit number controls another 4066 switch and again returns a resistance
which is seen by a separate 555 timer.
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The lights-and-whistles payload is controlled by yet another 4066
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The sun and temperature sensor readings are then passed to the communications
system where they are transmitted to the ground station.
The C&DH system interprets a signal sent from the ground station to
toggle between sending sun or temperature sensor data. The CPU is designed
to trigger operation of the payload when the former receives a pulse
from the ground station.
YODA
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