Senior Design Hardware Presentation David Anthony
Outline CraneTracker Project Hardware Design Design Software Fabrication Process
CraneTracker Needed connectivity for highly mobile target Limited energy reserves Long term mission Light weight
CraneTracker Capabilities GSM Connection Integrated GPS Solid State Compass Solar Recharging Iris Connection Lithium Polymer Battery
GSM Connection Telit GE-865 module UART Communications External SIM Card
GPS MediaTek MT-3329 Module Integrated Antenna NMEA 0183 Connection –Interchangeable with many other solutions
Solid State Compass Honeywell HMC-6343 Heading, pitch, roll 3D Acceleration Temperature Not just magnetometer
Solar Recharging MCP Needed for LiPo battery Not just for solar recharging –USB –Battery 7V Maximum
Iris Connection 51 Pin Hirose DF-9 Can be used with most motes in lab Iris provides microcontroller, flash, ZigBee
LiPo Battery Can use any single cell battery Why LiPo? –High energy density –Flat discharge characteristics –3.7V nominal voltage
Design Considerations Connectivity needs Sensing needs Processing & Storage Power supply needs –Driven by other considerations –Possibly most challenging part RF Needs
Connectivity Mobility Cost Range
Sensing What do your clients want? What do you need? –Had to add current and voltage detectors to crane project
Processing and Storage Keep it simple –Use motes in lab if possible Mission duration?
Power Supply Consider your power source –Snow plow, several options –Pheasant team, probably solar –What are the differences? What are your power needs? –GSM has high peak power consumption –GPS is also power hungry –Microcontroller, compasses, are negligible How sensitive are components?
Radio Frequency Can be extremely difficult Hard to replicate problems Hard to test
Design Process CraneTracker was designed completely in Altium EE Department has licenses for the labs Eagle is your best free solution
Design Process Part 1 Gather requirements Choose components Examine requirements of those components
Design Process Part 2 Design schematic Defines logical connections Does not describe physical layout Mistakes made here are extremely difficult to correct –Plan to spend a lot of time here –Use independent reviews to ensure accuracy
Schematic View
Layout The physical realization of your schematic Not as fun as it sounds Correctly implemented schematics ensure the automatic rule checkers detect your problems here
Layout
PCB Layout Defining different layers of board –Fabrication process is like developing a photograph Top & Bottom Copper Silkscreens Soldermasks
Design Rule Checker This will save you Define the rules you want your design to conform to –Minimum widths –Neckdown rules Finds erroneous connections
Fabrication Process So you’ve got a design… First question: –How much of the process do you want done? –How much of the process can you afford? Who is going to make it for you? –In the past, have used Advanced Circuits –Based in Colorado, so fast shipping –Great student deals –Advanced Circuits can do whole board assembly Best if you’re going to make a lot
Fabrication, cont. From your design, create Gerber files and NC drill files –Machine readable descriptions of your process –Each layer has its own Gerber file Submit design to fab house –Most will run their own rule checker –Can produce many false positives –But when they don’t… Wait 1-2 weeks –Anticipate this in your schedules Find out everything you’ve done wrong Go back to beginning