Drink Master 8000
D. Ryan RhodesPCB Design Considerations
Drink Master 8000
• Creates a variety of water-based drinks from powders stored in the device.
• Two holding tanks for storage of multiple beverages.
• Device can self-clean, so solution cross contamination is eliminated.
Block Diagram
PIC32MX µCtrl
RN-41Bluetoot
hDesktop/Laptop
w/ Bluetooth
Valve x18
I/OA
toD
Force x4
AtoD
RTD x4
AtoD
18
44
4
IR IN x 4
3.3V
UA
RT
2
LCD
2UA
RT
Thermoelectric Peltier
2RPGRPG
3
I/OI/O
12V
BuckConverte
r
Linear Regulato
r
3.3V
3.3VV
CC
GN
D
3.3V
VC
CG
ND
3.3V
3.3V
12V
3.3V
3.3V
IR IN x 4
3.3V
5V
Design Schematic
Micro
Solenoid Valves
BluetoothModule
PeltierControl
BuckConverter
LinearRegulatorWeight
Sensors
RTDSensors
IRRX/TX
LCD/RPG(need to
add)
RJ12
PCB Design: Microcontroller
DIP Switch
Considerations
• Large number of Ports used (location important)
• Decoupling/Bypass Caps
• Dip Switch for Debug/Reset/ETC
• Debug/In-circuit programming RJ12 jack
Figure 1.) PIC32MX Micro and Immediate peripherals
Pic32
RJ12Jack
Sensors
6
PCB Design: Power SupplyConsiderations:
• Need a large 12V supply and ground rail for Solenoid and Peltier• Have a 12V Trace (250-300 mil?) on
bottom of board at “north” edge?• Large Ground Plane (200 mil?) across
middle of most of the board?• Expecting 16 valves * 0.5 A * 12 V +
2 valves * 1.5 A * 12V = 132 W on top edge 12V rail
• Expecting 6A * 12V = 72 W for Peltier supply
• Need to minimize EMI for FCC/reliability reasons. Use multiple small parallel ground “rails” that connect to a single main ground?• See next slide for example
• Need to supply 3.3V to the other side of the board. How is it best achieved? Power rail on bottom board with vias near central points?
+12Von
Board
Fu
se
Bu
ck
Con
vert
er
Linear Regulat
or
Figure 2.) Power Supply
Key:
• GND(bottom)
• GND (top)
• 3.3V (bottom)
• 3.3V (top)
• 12V (bottom)
• 12V (top)
PCB Design: Power Rail Layout
12V Large trace (bottom)
Ground Rail (bottom)
3.3V Supply (bottom/top)
Figure 3.) Potential power supply rail layout
Questions/Comments?
Top Related