COMPUCCINO

1. 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

3. 8051 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 1st 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

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

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 Relay off Control 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 Reservoir Water Level Sensor Pot Valve Hot Plate

20. Schedule

21. QUESTIONS???