ECE 4884 : Senior Design

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ECE 4884 Senior Design

• LightSaVers

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Outline
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Project Overview

• Automated light balancing via remote blinds and
  dimmers
• Centralized, low-power wireless network
• Low bandwidth information feed via remote sensor
  network
• LED-based light fixture

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Medium Level Schematic
Cypress PSOC
Cypress PSOC
Cypress PSOC
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ZigBee Network

• Shot range mesh network
• Low power - 30mA/3µA
• Data rates _at_ 250kbs

Standard Bandwidth Power Consumption Comparison
Wi-Fi Up to 54 Mbps 400mA/20mA Overkill
Bluetooth 1Mbps 40mA/0.2mA High power
X10 8bps Negligible Two slow
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Network Perfomace

• Light sensor sampling directly via ZigBee
• UART between microcontroller ZigBee
• Central controller makes decisions and sends
  commands for light blind modules

DAC Dimming
Digital outputs Motor control
TX
ADC
Cypress PSOC
ZigBee
ZigBee
Light sensor
RX
UART _at_ 19200 baud
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Design Problems

• Unsuccessful at getting UART to work on PIC
• Light dimming via current modulation required a
  DAC not available on PIC

Tradeoffs

• PIC replaced by more expensive cypress PSOC
• Cypress PSOC provided an easy UART interface
  along with DAC

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Status Quo

• Transmitted sensor values using ZigBee
• Implemented light dimming via DAC on PSOC
• Controlled stepper motor using digital outputs on
  PSOC
• Transmitted and decoded commands from the central
  controller

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Future Work

• Implement solution in Aware home and tweek
  performance
• Replace PSOC with cheaper compatible
  microcontroller
• Reduce design to minimum possible microcontroller
• Replace Maxstream XBee with cheaper ZigBee modules

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Testing

• Cover sensors and simulate the flowchart
• System will not be run for a long period of time
  due to robustness issues
• Blinds may be operated manually pending
  mechanical mounting of the stepper
• The power savings will be tested by measuring the
  current flowing to the light fixture vs. that of
  an incandescent light bulb

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Questions?