Michael Davies Andrew Mountain Dan Hoang Daniel Brink Michael Davies Andrew Mountain Dan Hoang Daniel Brink Power Distribution Control Unit
Functionality Power Distribution Control Unit for Colorado Space Grant’s Satellite Citizen Explorer Implement commands from the satellite’s flight computer to provide the desired power to the unit’s subsystems Monitor specified temperatures and power buses
Schematic
17 – 4-Pin solid state relays Control using 5V logic Direct I/O with PIC Connected with desired voltage Distribution of Power
Schematic
Voltage Divider Maximum range voltage – low power consumption Analog multiplexer A/D converter on chip Temperature
Schematic
Power Supplies Rigorously test power supplies Power draw on each bus Concern with noise on 5V power bus –Pi-Filter near each chip that require 5V
PCB Board 4-Layer Board 2 Parallel 7.15" X 7.65" boards Through hole parts for stability 7.15" X 7.65"
Parts List Microcontroller: PIC 16C77 Relays: DMO063 Clock: ACH MHz Thermistor: YSI v to 15v/-15v Converter: JR12D v to 24v Boost Converter: SI12S v to 5v Converter: LANC1205W5S Flight Computer Interface: RS485/422 Max3082ESH PC Interface: Max208CN6
Microcontroller
Relays
Thermistors
Flight Computer Interface Serial Communication
PC Interface
Basic Software Functions INITIALIZE VOLTAGES CURRENTS TEMPS DELAY SEND INFO?
Basic Software Functions VOLTAGES SET ANALOG SWITCH POS 1 A/D CONVERSION SAVE VOLTAGE 1 SET ANALOG SWITCH POS 2 SAVE VOLTAGE 2 SET ANALOG SWITCH POS n SAVE VOLTAGE n RETURN
Basic Software Functions INTERRUPT RECEIVE TRANSMIT OTHER? RETURN
Basic Software Functions RECEIVE SET RELAYSSEND INFO RETURN READ BYTE
BOOT SEQUENCE CD&H 1 min delay ADCS 3-5 sec delay Mnet 3-5 sec delay Science 3-5 sec delay Deploy REQUIRED -extra delay for FC ARBITRARY Basic Software Functions
Schedule
Division of Labor Michael Davies: Software Andrew Mountain: PCB/Schematic Design Daniel Brink: Hardware layout Dan Hoang: Hardware/Software interfacing
Milestones Milestone 1: Completed Prototype (wire wrap) and interface-able test code Milestone 2: Completed PCB Design and ready to order (first revision) Design Expo