LOW POWER SENSOR NODE DESIGN Focused on H/W changes on ARTS FIPS Yoon Mo Yeon RTLab. KNU

Contents  Introduction to LPSN  H/W changes on ARTS FIPS  MCU + RF  Power  Sensors  Current Consumption  Summary  Further Works

Introduction to LPSN  Low Power Sensor Node  Based on ARTS FIPS  Battery powered  Can last about 1-year  Low current consumption  Low duty cycle  Hardware Features  MSP430F2618 MCU + CC2520 RF Transceiver  Simplified 3.3V operating voltage

ARTS FIPS  Block Diagram

Changes on MCU+RF  FIPS  Multi Processor  8 bit core(ATmega128)  CC2420 or CC2430  LPSN  Single Processor  16 bit core (MSP430)  CC2520 MSP430 F2618 CC2520 SPI ATmega 128L ATmega 8L CC2420 SPI UART UART

MCU + RF current consumption  Current consumption from datasheet (Unit : mA) MCURFLPMActiveRXTX ATmega128LCC CC MSP430F2618CC

Power Modes of CC2520  Current consumption of each power mode and Wake-up time RX 18.8 mA TX 25.8 mA Active 1.6 mA LPM1 175 uA LPM1 30 nA 0.2 ms 0.3 ms 192us

Changes on Power  FIPS  LPSN  Simplify power into 3.3V  Constant output voltage

Changes on Sensors  Re-design 5V circuitry into 3.3V  Smoke detection sensor : minor changes  PIR (Movement detection) sensor : minor changes  Flame detection sensor : under testing  Temperature Sensor : change part

Current Consumption of Sensors  Test environment DC Power Supply Digital Multimeter Oscilloscope FIPS Layer 1 Flame & PIR Sensor Layer 2 Smoke & Temperature Sensor

(uA)

Summary  Simplified 3.3V operating voltage can reduce current consumption of sensors significantly  But sensor gives a little deal of weight on current consumption of entire system when active

Further Works  Complete the hardware design of LPSN  Check the transformer for flame detect sensor  Find appropriate temperature sensor for 3.3V operation  Verify each sensor works correctly  Research another method to reduce current consumption of sensors

Q & A  Predicted lifetime of LPSN  Battery capacity : 1000mA  Charge pump efficiency : 70%  Can last about 60hr. in Active Mode  Can last about 2333hr.(97 days) in LPM  1% RF(TX), 9% Active, 90% in LPM can last about 444hr.(18 days)

End of Presentation