The myHome System

1. The myHome System An Adaptive Environment with a Low-Power Transmitter Group #35 Sameer Kalwani | Vinayak Sathyamoorthy | Harry Thakkar

2. Design Overview

3. Why the myHome system? • Convenience • Simplifies everyday life, by having the technology and environment adjust to users, rather than they to it • Economical solution for the average consumer • Can be purchased for a couple hundred dollars • System promotes energy efficiency; saves money for homeowners, corporations, and hotels by limiting high energy bills • It’s the cost-effective alternative, as compared to other technologies like GPS, Bluetooth, and RFID • Creates a customizable environment for a person entering a certain room • All you need is a small, low-power transmitter • Transmitter communicates with a base station inside room - it changes the lighting, temperature, and music of that environment • System is geared towards user safety • Light settings will avert people from bumping into objects at night • Temperature settings prevents people from getting hypothermia • System has potential to be high compatibility with other high-frequency home devices • Radios (intercom system) • Garage door openers (convenience and safety) • Wireless phones (emergency 911 calls)

4. Features • Customizable Lighting, Music and Temperature settings for Each User • Multiple “Mood Settings” • Work, Sleep, Romantic • Built-In Digital Thermostat • Expandable, Modular Design • User can be detected up to a distance of 300 feet • Adaptive Environment for Multiple Users • Functionality with many different-sized rooms (small, medium, large) • “Sleep” Mode for Transmitter, reducing the number of battery replacements • Built-In Digital Thermostat

5. Wireless Applications • Operating in the 315/418 MHz Range • LINX RXM-(315/418)-LC • LINX TXM-(315/418)-LC • Two transmitter/receiver modules – one for user side, one for base station • User side • Receive signal  PIC access  Transmit user data • Base Station side • Receive user data  Interprets current user state  Sends ping to user to detect if state has changed

6. User Module • Components • TXM-418-LC • RXM-315-LC • PIC Microcontroller/ 20 kHz Oscillator • Awaits PING from Base Station (Transmits Datastream

7. User Datastream • Start Bit: 0 – 1 bit, transmitted prior to data • Ping Bitstream: 00101110 – 8 bits, LSB transmitted first • Stop Bit: 1 – 1 bit, transmitted after data 0 1 1 1 1 0 0 0

8. User Module Power • Tadiran 3.6 V Lithium Ion Battery • Rated at 2400 mAh • Two Batteries in Parallel • Power Consumption • Transmitter & Receiver: 3mA + 6mA = 9 mA • PIC: 7 mA • Oscillator: 15 mA • Battery lasts for 6.5 days with continuous power supply

9. Low-Power Implementation • Slave Mode • In Sleep mode, the slave can transmit/receive data • When byte is received, wake-up from Sleep • Power Consumption (sleep) • Transmitter & Receiver: 1.5 µA + 6 mA = 6.0015 mA • PIC: 1.5 µA • Oscillator: 15 mA (~70% power consumption) • Battery lasts for 9.5 days sleep • At 20% active, battery will last for ~9 days

10. Base Station • Components Required For Circuit: • 1 PIC16F877A, 1 TXM-315-LC, 1 RXM-418-LC, 1 47kΩ Resistor, 1 20 Mhz Oscillator

11. Base Station Ping • Start Bit: 0 – 1 bit, transmitted prior to data • Ping Bitstream: 10000000 – 8 bits, LSB transmitted first • Stop Bit: 1 – 1 bit, transmitted after data

12. Datastream Reception • Data Stream Received at Base Station • Slight delay between transmission and reception of data Delay

13. Data Stream Contents User Flag: Flag used by PIC to begin parsing data Lighting Control: 4 different light settings Temperature Control: 16 different Temperature settings – 64 to 79 degrees TV Flag: Flag used by PIC to turn on TV

14. Base Station PIC Coding • Send pings at regular intervals • If data detected on RX pin, interrupt called and data moved to registers • Exit interrupt, begin parsing data • Check for multiple users • Send parsed data out to applications

15. Multiple User Transmission

16. Multiple User Conflict Resolution • If (UserID1 && UserID2 && UserID3 == 1) Then • Average User Temperature Values • Average User Light Values • Use User1 TV settings • Output Parsed Data • Else If [(UserID1 && UserID2 == 1) || (UserID1 && UserID3 == 1) || (UserID2 && UserID3 == 1)] Then • Average User Temperature Values • Average User Light Values • Use Lowest Users TV settings • Output Parsed Data

17. PIC Power Consumption on Base Station

18. Environmental Applications

19. Environmental Applications Temperature

20. Environmental Applications Temperature-Thermostat • Components Required for circuit: • 2 1kΩ Resistors • 2 10kΩ Resistors • 1 120kΩ Resistor • 1 56kΩ Resistor • 1 6MΩ Resistor • 2 100nF capacitors • 1 100µF capacitor • 1 470µF capacitor • 2 1N4148 Diodes • 1 5V1 Zener Diode • 1 BC547 NPN BJT • 1 VR15M121C Relay switch • 1 DS1804-100 100k Ω Digital Potentiometer • 1 LD1Red LED • 1 NTC10K0 (sensor across SK1) • 1 LM324 OpAmp IC Thermostat circuit Velleman-kit: MK138 http://www.velleman-kit.com

21. Environmental Applications Temperature Display • Components Required for circuit: • 2 LSD3211-11 Displays • 2 CD4511BE BCD to 7-segment Display Decoders Thermostat Display Circuit

22. Environmental Applications • Controlled using the DS1804-100 Digital Potentiometer. • Since the Thermostat’s set temperature is controlled using the a mechanical potentiometer, we decided to replace it with an electronically controlled digital potentiometer. • The DS1804 is a non volatile digital potentiometer with EEPROM memory • Wiper position of the DS1804 can be stored in EEPROM memory on demand. The device’s wiper position is manipulated by a three-terminal port that provides an increment/decrement counter controlled interface. This port consists of the control inputs CS , INC , and U/ D. • These input signals control a 7-bit up/down counter.Al • Altering the position of the Wiper tap-point (which is the current resistive value)

23. Environmental Applications Infrared Communication

24. Environmental Applications Infrared Communication • Components Required for circuit: • 1 2kΩ Resistor • 1 1kΩ Resistor • 1 22kΩ Resistor (used for obtaining a 40kHz signal) • 2 1N4148 Diodes • 1 Infrared LED • 1 10nF capacitor • 1 1nF capacitor • 1 220nF capacitor • 2 1N4148 Diodes • 1 LM555 Timer Infrared Circuit

25. Environmental Applications How the Infrared Transmitter Works • This IR transmitter sends 40 kHz (typical frequency of IR TV transmissions) • The circuit is controlled using a microcontroller, in this case PIC16F877A. • Using the LM555 counter, the circuit emits a signal at the appropriate frequency, to send the inputted serial data signal over the IR LED .

26. Environmental Applications IR Input/Output IR Modulation http://www.xs4all.nl/~sbp/knowledge/ir/sirc.htm IR protocol uses a pulse width encoding of the bits. The pulse representing a logical "1" is a 1.2ms long burst of the 40kHz carrier, while the burst width for a logical "0" is 0.6ms long. All bursts are separated by a 0.6ms long space interval. The recommended carrier duty-cycle is 1/4 or 1/3. The TV’s Address code is “1.” IR Protocol IR Input/Output (zoomed in) http://www.xs4all.nl/~sbp/knowledge/ir/sirc.htm

27. Environmental Applications Lighting

28. Environmental Applications Lighting • Components Required for circuit: • 2 330kΩ Resistors • 2 27kΩ Resistors • 1 10kΩ Resistor • 1 0.1µF Capacitor • 40W Light bulb • 1 Porcelain light socket • 1 3-Prong outlet • 1 AN1001 Triac • 1 1:1 Pulse Transformer • 2 1N4003 Diodes • 1 2N4403 PNP BJT • 1 2N5551 NPN BJT Lighting Circuit

29. Environmental Applications Lighting (cont.) Potentiometer Components • 1 CD4052BCN Analog 4-to-1 Multiplexer • 3 800kΩ resistors • 3 3.2MΩ resistors Potentiometer Circuit

30. Environmental Applications How Dimming Works • To regulate the voltage across the lamp load, the two transistors act as a “flasher,” which regulates the power transformer. • The two diodes rectify the line voltage such that the flasher sees a positive voltage pulse on each half-cycle • A delay is set by the digital potentiometer and the 0.1uF capacitor, causing the flasher circuit triggers the triac. • The capacitor discharge is deep so the dimmer starts fresh on the next half-cycle. • Note that the voltage stored in the capacitor is regulated by the Digital Potentiometer, thus by altering the voltage we regulate the amount of voltage across the light. • Essentially the light load is being powered by voltage stored in the capacitor. The Dimmer is more of a flickering mechanism, rather than a direct source of power. The frequency of the driven power, regulates the amount of power consumed by the light load.

31. Testing • Modular Testing • Worked on Three Pieces Separately • Wireless & PIC Implementation Brought Together, Followed by Environmental Applications

32. Wireless Communication • First test the chips – do they produce a signal? • Wired Communication  Chips Work

33. Wireless Transmission • Test Transmitter for Wireless Transmission • Spectrum Analyzer • Shows strength of signal, clarity

34. Distance Measurements • Analyzed via Spectrum Analyzer • Signal starts deteriorating beyond recognition at ~45 feet • Function of type of antenna being used (helical vs. whip)

35. PIC Troubleshooting • Was Unable to Program first PIC • Need High Frequency Oscillator • MCLR Pin Must be pulled high

36. Testing in MPLAB

37. Testing of Environmental Apps Testing Procedural Test Flow • Implement circuitry design • Measure outputs • If outputs are as expected, move on. Otherwise, look are more basic elements and find which element is causing the error. • Once error element is identified, look to see if it has been implemented appropriately. If it has, look within it to find the next element causing the error. Otherwise, find the appropriate method of implementation.

38. Future Additions • Universal Implementation • Extend Bit Stream • GUI Interface • For Users to Update Preferences on their module • USB updating of the PIC on the user module • PCB Mounting • High power/quality antennas • 911 Emergency Dial, and other convenience features

39. Ethical Considerations • Comply with FCC regulations governing RF devices • Honest & realistic about claims based on available data • Low power transmitter • Safety warnings when dealing with Light Dimming • Complying to customer needs, when it comes to implementation and production

40. Special Thanks • Parts Shop Staff • Dan Mast & Crew • Alex Spektor • Professor Scott Carney • Al Gore (the Internet) • The ECE Department