Download Low power sensor node design

LOW POWER SENSOR
NODE DESIGN
Yoon Mo Yeon
RTLab. KNU
Focused on H/W changes on ARTS FIPS
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
CC2420
SPI
ATmega
128L
UART
ATmega
128L
ATmega
8L
UART
LPSN
 Single
Processor
 16 bit core (MSP430)
 CC2520
CC2520
SPI
MSP430
F2618
MCU + RF current consumption

Current consumption from datasheet (Unit : mA)
MCU
RF
LPM
Active
RX
TX
ATmega128L
CC2420
-
11
37.8
36.4
0.2
9.5
26.7
26.9
0.2
9.8
35.6
28.6
CC2430
MSP430F2618
CC2520
Power Modes of CC2520

Current consumption of each power mode and
Wake-up time
192us
RX
18.8 mA
TX
25.8 mA
192us
192us
Active
1.6 mA
0.2 ms
LPM1
175 uA
0.3 ms
LPM1
30 nA
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
Layer 1
Flame & PIR Sensor
FIPS
Digital Multimeter
Layer 2
Smoke & Temperature Sensor
Oscilloscope
The relation between supplied voltage and
current consumption of sensors
Flame
PIR
Smoke
Temperature
Total
(uA)
298.64
176.61
117.78
107.96
110.73
58.11
58.09
57.36
50.47
14.79
5.0V
58.00
27.21
16.50
9.02
10.69
4.2V
3.3V
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
LPM (0.3mA)
Active (11.5mA)
MCU
34%
RF
33%
RF
14%
RX (35.7mA)
Sensors
0%
Sensors
1%
Sensors
1%
Sensors
33%
TX (27mA)
MCU
28%
MCU
36%
MCU
85%
RF
63%
RF
72%
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