Drink Master 8000 D. Ryan Rhodes PCB 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-41 Bluetooth Desktop/Laptop w/ Bluetooth Valve x18 I/O AtoD Force x4 AtoD RTD x4 AtoD IR IN x 4 3.3V UART2 LCD 2 UART Thermoelectric Peltier 2 RPG 3 I/O 12V Buck Converter Linear Regulator 3.3V VCC GND 3.3V VCC GND 3.3V 12V 3.3V IR IN x 4 3.3V 5V

Design Schematic Micro Solenoid Valves Bluetooth Module Peltier Control Buck Converter Linear Regulator Weight Sensors RTD Sensors IR RX/TX LCD/RPG (need to add) RJ12

PCB Design: Microcontroller 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

PCB Design: Power Supply 6 Considerations: Need a large 12V supply and ground rail for Solenoid and Peltier Have a 12V Trace ( 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? +12V on Board Figure 2.) Power Supply

Key: GND(bottom) GND (top) 3.3V (bottom) 3.3V (top) 12V (bottom) 12V (top) PCB Design: Power Rail Layout Figure 3.) Potential power supply rail layout

Questions/Comments?