ECE 477 Design Review Team 3  Spring 2009

Outline Project overviewProject overview Project-specific success criteriaProject-specific success criteria Block diagramBlock diagram Component selection rationaleComponent selection rationale Packaging designPackaging design Schematic and theory of operationSchematic and theory of operation PCB layoutPCB layout Software design/development statusSoftware design/development status Project completion timelineProject completion timeline Questions / discussionQuestions / discussion

Project-Specific Success Criteria Propel a projectile from the coil gun. Operate with at least one coil at fire time. Report charge status and readiness. Measure and report transient properties (such as muzzle velocity) of the projectile. Track and Display.

Project Overview Multi-stage coil gun capable of propelling ferric projectilesMulti-stage coil gun capable of propelling ferric projectiles Driven with 9v battery and includes battery backupDriven with 9v battery and includes battery backup Report transient properties of projectile to LCDReport transient properties of projectile to LCD

Block Diagram

Component Selection Rationale Microcontroller Constraints:Microcontroller Constraints: –Fast computation speed Projectiles will hopefully be going fastProjectiles will hopefully be going fast Short distance between sensors and from sensors to coilShort distance between sensors and from sensors to coil –Large number of external interrupt pins –6 ADC channels –Good support –Large amount of Flash –1 SPI port Switching transistor constraints:Switching transistor constraints: –Very high Collector-Emitter current –Fast switching time

Component Selection Rationale PIC32MX360F256L – –80MHz, 125 MIPS – –256 KB Flash – –22 Interrupt-on-Change pins – –Up to 16-channel 10-bit ADC – –Excellent Support – –256K Flash – –2 SPI ports, various other serial protocols IRGPS60B120KDP IGBT – –104 Amps I CE – –50ns switching speed

Packaging Design

Schematic/Theory of Operation 1

Schematic/Theory of Operation 2

PIC Microcontroller

PIC Top View

PIC Left View

PIC Bottom View

LCD & PIC - Right View

3.3V Buck/Boost

Coil Discharge Circuit

Coulomb Counter

PCB Layout Considerations 4 PCB total: 1 main and 3 smaller discharge circuit PCBs4 PCB total: 1 main and 3 smaller discharge circuit PCBs EMF protection to circuitryEMF protection to circuitry –~5v measured EMF around single coil –Faraday cage around all coils Large trace widths to power and ground for coil discharge circuitLarge trace widths to power and ground for coil discharge circuit Main PCB width to remain under 3” to fit onto rifle. More leeway with PCB length.Main PCB width to remain under 3” to fit onto rifle. More leeway with PCB length.

PCB – Main Board

PCB - PIC

PCB - LCD

PCB – Power Circuit

PCB - Component Layout

PCB Discharge Circuit

Software Design/Development Status DesignDesign –Timer interrupt to handle LCD updates via SPI –External interrupts to handle push buttons –Input capture to handle optical sensors –Calculate velocity based on distance/time between sensors –Output compare to handle trigger timing –Final timings = velocity calculation + empirical observation Development Status:Development Status: –Learning development toolchain/examples –Somewhat familiar with architecture –Not anticipating many problems

Project Completion Timeline

Questions / Discussion Optional Camouflage Painting, $30