README.md
Purpose

The Braking IO board (generically called Remote IO or RIO boards) are responsible for managing the sensors and actuators on each of the braking trays. Previously, we routed several dozen wire harnesses across the majority of the pod in order to connect to the pressure sensors and solenoids. This board reduces all of that routing into a single power harness, UART + Heartbeat cable and allows for more localized routing to each of the sensors and actuators on the tray. Eventually, there will be 2 of these boards on the pod; one for each braking tray

Requirements


Mechanical:


Board shall have at least four 4-40 mounting holes
Board shall fit in the mechanical enclosure
Bonus: Board shall contain at least three fiducals for potential automated assembly

Connector Interface:


Connectors shall be properly rated for voltage and current
Connectors shall have a positive locking feature
Connectors shall share a common pinout and be polarized
connectors shall be kept to a minimum
Bonus: System shall be designed for 1:1 harnesses in order to use off the shelf cable assemblies as much as possible.
Bonus: Harness ID pin shall be added to each connector in order to detect if each cable is properly connected or not.

Power:


Fusing: Bus input shall be fused to protect against over-current events
Telemetry: All rails shall have voltage and current sensing
Filtering: Bus voltage shall be filtered
Rails: 5V and 3V Rails shall be implemented

Sensors:


Pressure: Pressure telemetry inputs (8x) shall be configurable for both voltage and current output pressure transducers
Temperature: Two configurable board mount or external temperature sensors shall provide temperature feedback

Actuators:


Solenoids: 8x solenoid driver circuits shall be implemented
Bonus: Use the MPQ6610 instead of a traditional N-MOS driver to save on power
Bonus: LEDs on each solenoid

Watchdog:


Board shall have a way to reset all solenoids in case of loss of heartbeat or UART connection from either the microcontroller or the primary flight computer

MCU:


Board shall be capable of sending telemetry, over UART, to the primary flight computer
Board shall be capable of receiving commands to actuate different valves, over UART, from the primary flight computer



Info


Schematic Designers @btobin @rcastle1
Layout: @btobin
Need-by-date: 10/1/2019