Nucleus Altitude ControlDynamics Sensor Card

Theory of Operation

Main Processor

Communication and Control Interfaces

Altitude Control System

This subsystem contains the systems required to control the ballast portion of altitude control.

Dynamics Sensors

This subsystem is primarily a set of interfaces off the card to sensor nodes located throughout the HAB. The goal is to collect data from multiple points to create a model of the vehicle during flight. This will assist in validating movementmotion models and inform decisions for future attitude control systems.

Power Management

Electrical Implementation

Note Red represents power and blue represents data signals

Major components

Microcontroller - STM32F407VET6TR
CAN Transceiver - TCAN1051
Pressure Sensor - BMP388
9 DoF IMU - ICM-20948
Temperature Sensor - TMP117A
Ethernet PHY - KSZ8081MNX
Voltagecurrent monitor - INA3221

Power Supplies

A list of devices per rail is provided below, as well as expected current requirements based on a power analysis of the hardware stack. The detailed analysis is available through the following google sheets link:
Hardware Stack Power Analyses

12V Power Rail

• 6V Switching Regulator
• E-Fuse

405mA current draw

6V Power Rail

• Servo Channels
• Motor Channels

764mA current draw

5V Power Rail

• 3.3V Switching Regulator
• 1.8V Switching Regulator
• E-Fuse

73mA current draw

3.3V Power Rail

• CAN Transceiver
• Ethernet Transceiver
• Microcontroller
• ADC
• Temperature Sensor

89mA current draw

1.8V Power Rail

• IMU
• Pressure Sensor

4.5mA current draw

Power Considerations

Per the power analysis, it is expected that the Altitude ControlDynamics Card will draw approximately 1007 mW of power during nominal operation. This analysis also includes 125mA current flowing through each motor channel and 250mA through each of the servo channels. These are initial estimates and will be updated during further documentation review and board testing

Design Implementation

Connectors

Backplane

There is one 28 pin Molex MilliGrid shrouded right angle connector providing all interfaces to and from the Avionics Sensor Card to the Backplane and Main Flight Computer.

Molex Part # 0878332820

Reference view for pinout of connector is from top edge of board looking towards backplane connector.