COMPUCCINO Kalani Rathnabharathi Vithya Shanmugam Robert Armstrong Aaron Kulp

2 Power Supply  Converts 110VAC to 12VDC & 5VDC  Components: –5:1 Transformer Converts 110VAC to 22VAC –Full-Wave Rectifier Bridge Rectifies the AC voltage –UA7812 Regulator Smoothes out the ripples and give 12VDC –UA7805 Regulator Converts 12VDC to 5VDC –LED Indicators  Diodes on regulators prevent backflow of current through the regulators

Processor  The core of our local embedded system will be an 8051 processor in tandem with an XC2S100 FPGA  The primary function of this processor will be to monitor and control the sensors and features of the coffee pot

4 Embedded Peripherals  8051 platform has the following on-board peripherals: –I2C EEPROM –MAX118 A/D Converter –DS1302 Real-Time Clock –MAX232 for RS-232 level conversion –20x4 Character LCD

5 Memory Map  To enable the use of a monitor/debug program, we have combined the memory map into one 64K block  If more than 32k of code is necessary, we can split the map into RAM/ROM

6 Main Program Outline “Pseudo” Code: Main() { Initialize timers; Initialize interrupts; Initialize serial I/O; Initialize peripherals; for(;;) { Check for/respond to remote commands; Check for/respond to local commands; Refresh sensor data; Redraw local user interface; }

7 A/D Conversion  Over half of our sensors require analog to digital conversion, which will be accomplished with a MAX118  The MAX118 is an 8-bit, 8 channel 5V sigma-delta analog to digital converter –This gives us an effective resolution of approximately 20 mV –Any further resolution would be irrelevant in our prototype board, because signal noise would cause fluctuations in the voltage leading to us needing to discard the least significant bits  In order to avoid signal timing issues and to get the greatest possible processor bandwidth, we have configured the MAX118 to fire an interrupt when the conversion is complete

8 A/D Conversion Timing

9 Water Level Sensor  MPX4115A pressure sensors  Two LM358 op amps cascaded together  Output of 1 st op amp acts as a summing node for the difference between Vreference-Vmeasured  Output of second op amp will be: 5V –100Out1

10 Water Level Design Consideration…  Design Consideration One : We need an initial reference point pressure and corresponding voltage  Design Consideration Solution One : We will use barometric pressure as the reference point By utilizing a differential op amp, we can isolate our measured water level pressure reading from the barometric pressure, giving us the corresponding water level  Design Consideration Two : Voltages outputting from first differential op amp will be amplified by 100x. We need to compensate for negative voltages.  Design Consideration Solution Two: We will cascade two op amps together, The output of our second op amp will be 5V-100Out1

11 Water Level Test Results  Test to determine what voltage corresponds to particular water level  Recorded:  Conclusion: Water Level versus Voltage is a linear relationship Cup Size Voltage V V V V V V V V V

12 Water Quality Water Quality Sensor-Milestone 2 Coffee Pot 5V Resistor ADC

13 Hot Plate Control  Active high control from 8051 I/O  Relay – 12V controlling 120VAC  Fuse protection at 227ºC

14 Blender Control  Active high control from 8051 I/O  Relay – 12V controlling 120VAC

15 Control Waveforms Control Relay off Relay on

16 Blender Demo

17 Pot Temp Sensor  Option1 - Voltage divider  Option 2 – IR sensor  Output into an ADC

18 Hot Plate Temp Sensor  Voltage Divider  Output into an ADC  Thermistor – resistance is temperature sensitive.  Temp range – -50ºC to 250 ºC

19 Pump / Cup Size  Control valve according to reading of water level sensor  Mechanically controlled valve.  Control of pump: –Valve opens (remains open according to cup size) –Water flows from reservoir to hotplate –Pressure build up pushes water through grounds to pot.  Milestone 2 Water Level Sensor Reservoir ValvePot Hot Plate

20 Schedule

21 QUESTIONS???