Senior DesignHardwarePresentation

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-73831• 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