1 / 39

Smart Alarm Clock

Smart Alarm Clock. By: Paul Lee Arthur Wu Jordan Yamamoto. Table of Contents. Objectives Hardware Software Testing/Data Troubleshooting Project Timeline Cost Analysis Future Considerations Sales Pitch Acknowledgments. Objectives.

jana
Download Presentation

Smart Alarm Clock

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Smart Alarm Clock By: Paul Lee Arthur Wu Jordan Yamamoto

  2. Table of Contents • Objectives • Hardware • Software • Testing/Data • Troubleshooting • Project Timeline • Cost Analysis • Future Considerations • Sales Pitch • Acknowledgments

  3. Objectives • Punctuality: make appointments and class on time and start off the day in good order • Oversleeping Prevention: break bad habit of falling back to sleep • Convenience: People only have to set alarm, and the sensors will take care of everything else. People will be rest assured that the smart alarm clock will wake them up. • Cost: Productivity in companies can improve when people come to work on time, and more is accomplished over the day. Students will learn more in a classroom setting than their beds.

  4. Hardware • PIC 16F877 • Flexiforce pressure sensors • MTS102 Thermal Sensor • Genie Optical Safety Sensor • Amplifiers • BCD-to-LED decoders • 4 Seven Segment displays • Piezo Buzzer • 4.00000 MHz Oscillator

  5. PIC 16F877 • 40 pin microcontroller • Ports A,B,C,D,E • On-board 8 channels of A/D converters • Oscillator input • The Smart Alarm Clock’s Microcontroller

  6. PIC • Each Port has 8 bits, either input or output • Port A • Sensor inputs • Port B • Time display (minutes) • Port C • Time display (hours) • Port E • Output buzzer

  7. PIC • PIC • Each sensor outputs to PIC’s A/D converter • Each sensor output = 8 bits of data • PIC takes sensor input and compares to 0 • Clock output goes to BCD-to-LED decoders • Decoders output times to 7 segment displays • One output pin sent to piezo buzzer

  8. Flexiforce Sensors • 3 located at the head, shoulders, and butt • Creates a variable resistance • Only the tip is sensitive to pressure • Sewn to surface of bed • Piece of firm paper with glued on resistor used to focus pressure on sensing tip • D/A threshold value set to 0V

  9. MTS 102 Thermal Transistor and Temperature Circuit • 10mV differential output for each degree C • Output measured across transistor

  10. Assembly • Thermal Sensor • Duct taped to the top of the cot • Placed under location where shoulders are so body heat always detected • D/A threshold value set to be 0 V

  11. Genie Optical Safety Sensor • Creates current change if line of sight blocked • Voltage across 550 ohm resistor used to convert the current to a measurable voltage

  12. Assembly • Optical Sensor • Test tube clamp used to attach to cot • Sensors set up to scan diagonally across the bed • With a 550 ohm resistor, 2.26 V differential detected • Threshold value set to be 0 V

  13. Other parts • 7-Segment Display • Piezo Buzzer • Oscillator • BCD-to-LED 7448

  14. Circuit

  15. Software • Programmed PIC in C++ • Initially had limited knowledge • Controls clock time, alarm time, A/D for sensors, criteria testing for alarm output, buzzer

  16. Time Display I • Used port B (8 pins) to control four 7 Seg LED • Four pins control two BCD-to-LED (7448) • Required mapping • First hex corresponds to MSB • Gets sent to MSB BCD-to-LED • Second hex corresponds to LSB • Gets sent to LSB BCD-to-LED

  17. Time Display II • Example: if 08 is desired for output, sends 0000 to MSB and 1000 to LSB • 7448 chip turns on respective segments to display correct digit • subroutine “display” to see check MSB and calls respective BCD-to-LED mapping BYTE CONST LED_MAP0[10] = {0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09}; //0.. void display_mins0(char c) { … port_b=LED_MAP0[c-'0']; }

  18. ADC I • port A for sensors • Sensor’s analog signal converted to a digital value for comparison • 8 bit value for ADC reading • 5 channels • Read analog input at each channel • If greater than threshold (0V), sensor is ACTIVE • Else, sensor is INACTIVE

  19. ADC II • Check sensors each iteration (every second) • Must pass 3 of 5 tests to turn on alarm set_adc_channel( 0 ); delay_us(10); value = Read_ADC(); if(value>0) culmination++; else culmination = culmination; delay_us(10); if(culmination >= 3) sensor = 1; else if(culmination == 0) sensor = 2; else sensor = 0;

  20. Alarm Check • When clock cycles through, alarm case is checked • t1, t2, t3, t4 are compared to set alarm time • Pos1, pos2, pos3, pos4: characters that are mapped to be displayed • If 3 of 5 sensors are active & t1-t4 match alarm time, buzzer turns on if (min == 18){ pos1='8'; pos2='1'; t1 = 8; t2 = 1;} if ((t4==a4)&&(t3==a3)&&(t2==a2)&&(t1==a1)&&(sensor==1)){ output_high(PIN_E0);} else if(sensor==2) { output_low(PIN_E0);}

  21. Testing: Pressure • Conditioned sensors by stepping on them • Ensures output will be repeatable within 2.5% • Laid on cot to calibrate resulting output voltages • Variable resistance changed to ensure threshold will be broken if active • Amplified output to increase voltage difference between Active/Inactive states

  22. Measurements: Pressure • HEAD • Max 4 V • Min -312.5 mV • SHOULDER • Max 5.9 V • Min -616 mV • BUTT • Max 5.8 V • Min -440 mV • Conclusion • Expected Linear Response

  23. Pressure Sensor Data • Top: person present • Bottom: person absent • SNR (head): = [4-(-0.3125)]/[.213] = 20.2 • Output somewhat erratic

  24. Testing: Thermal • Amplified difference between room temp and active temp • Laid on cot to calibrate resulting output voltages • Variable resistance changed to ensure threshold will be broken if active • Discovered best placement of sensor • Underside vs top • Timed response to abrupt temperature changes

  25. Measurement: Thermal • Room Temp: -0.9 V • Max: 1.4 V • Time • 28 sec to rise above threshold of 0 V • 63 sec to hit peak 0.52 V • 23 sec to fall back below threshold

  26. Thermal Sensor Data • Top: person present • Bottom: person absent • SNR: = [.52-(-.9)]/[.0313] = 45.4 • Sluggish to react, but very reliable output

  27. Testing: Optical • Tested various resistances to obtain greatest voltage difference • 550 ohms • Blocked beam to calibrate resulting output voltages • Variable resistance changed to ensure threshold will be broken if active Volt (V) Resistance (ohms)

  28. Measurement: Optical • No Interference • -1.0 V • Interference • 4.25 V

  29. Optical Sensor Data • Top: person present • Bottom: person absent • SNR: = [4.25-(-1)]/[.250] = 21 • Highly reliable output

  30. Troubleshooting • PIC • Clock code • Is difficult to get the time exactly right with wait_ms() command • A/D converters • Difficulty encountered in utilizing multiple input bits at once • Keypad • Difficulty encountered in getting the KBD example code to successfully interface with our PIC

  31. Troubleshooting • Multiple defective pressure sensors, and each has a slightly different response • Have to be sure pressure sensors are not melted from soldering • A method had to be devised to turn the current to a measurable voltage • PIC accidentally fried at 7V and another at 12V • Placement of sensors • LED mapping using PIC • Learning A/D code

  32. Project Timeline

  33. Cost Analysis

  34. Future Considerations • Wireless sensors • Circuit on PCB • Use of actual bed instead of cot • More accurate timing of clock counter • Easy interface to input alarm times • More aesthetic product (no duct tape in actual product)

  35. Sales Pitch • “Never be late again with the smart alarm clock” • Ideal gift for someone who oversleeps • Appealing to busy college students and workers • Little hassle to set-up; sensors will take care of the alarm • Product guaranteed to make you leave your bed • Waking up has never been easier

  36. Acknowledgements • Professor Swenson, Mo, and Marty, our favorite professors and TAs • Amit ECE 411 TA • Jim Wehmer and all the other part shop staff • Machine Shop • www.datasheetarchive.com

More Related