Humble Hubble Team 18: Evan Foote, Doug Wile, Tim Brown, Derek Pesyna Background:

Abstract The proposed project is a self-aiming telescope. This telescope will obtain its global position and the local time via GPS. It will then automatically orient itself to point at a user selected target (star) using a variety of onboard sensors. Background:

PSSCs An ability to establish a coordinate system based on the telescope's absolute global position via a GPS chipset, and relative orientation based on an accelerometer and electronic compass. An ability to establish a coordinate system based on the telescope's absolute global position via a GPS chipset, and relative orientation based on an accelerometer and electronic compass. An ability to compensate for combined variations in the Earth's gravitational and magnetic field, and variations in telescope geometry and mounting configurations via electronic user calibration. An ability to compensate for combined variations in the Earth's gravitational and magnetic field, and variations in telescope geometry and mounting configurations via electronic user calibration. Background:

PSSCs An ability to retrieve celestial coordinates and targets via Bluetooth from an external host. An ability to automatically move and point the telescope at the designated target using feedback loops from integrated motor encoders. An ability to allow the user to manually override the telescope's target coordinate using an onboard electronic control interface, and to display information regarding headings on an onboard LCD. Background:

Block Diagram

Component Selection Rationale All on-board sensors are surface mount and 3-axis. GPS switched to on-board antenna, but not Bluetooth CPU selection rationale: Microprocessor PIC24FJ64GB106-I/PT - Microchip S912XDG128F2MAL - Freescale Program Memory (Flash)64Kb128Kb I2C Bus3 busses1 bus I/O Pins52 pins91 pins PWM Channels9 channels8 channels UART channelYes Operating Voltage V V Cost $6.26$7.22

Packaging Design

Schematic: Main Board

Schematic: Aux Board

Enable (High Z) PWM Signal Brake / Coast Focus on Motor Control

ON / OFF interrupt Hold Circuit on DPDT Latching Switch Focus on 3.3V regulator

Need to add headers Schematic: Sensor Breakout Board

PCB Layout Main Board PIC micro LCD header, shift register RS232 line driver/receiver Rotary encoders Sensor board headers Auxiliary board headers VEX encoders

PCB Layout Auxiliary Board GPS receiver H-bridges, associated logic 5V, 3.3V voltage converters 5V, 3.3V, GND Bluetooth module, 50 ohm antenna Bluetooth + GPS headers H-bridge + power headers

PCB Layout Sensor Board I2C + power headers Accelerometer Gyroscope Compass

Errata VDD/VSS for I2C and VEX on main board Replace temporary headers with real headers Change 100uF capacitor from SMD to through-hole on aux board Unconnected pins on microcontroller, sensors Make rotary encoder pads/hole larger

Software Design (Initialization) Start Init. Turn on GPS. Get reading Accel, compass reading Move to level position Move to point North Turn on Bluetooth, Connect Send GPS/time data to Android Android calcs calibration targets Select calb. target Telescope points to calb. target User centers telescope on target Init. Done

Software Design (Main Loop) Start Main Get target from Android Move to target Wait for new target

Project Completion Timeline Week Starting onEvanTimDougDerek 2/25/2013NothingBlink LEDAggregate Star dataSimple GUI 3/4/2013PCB parts feedbackI2C Exams 3/11/2013SupportSpring Break Build Mount 3/18/201340% PCB Populated and tested Test software/ software designSupport Fist Bluetooth over android 3/25/2013PCB populated and tested Test software/ software designSupport Fist Android app done 4/1/2013PCB debugged Low level development done high level software development done Android wiggle room 4/8/2013WRAP UP ALL THE THINGS 4/15/2013DEBUG ALL THE THINGS (and write the manual)

Questions?