View
25
Download
0
Category
Preview:
DESCRIPTION
A sensor network, that like ivy, spreads through the environment and links leaves to the root. Ivy – A Sensor Network Infrastructure for the College of Engineering. Jaein Jeong, Lance Doherty and Kris Pister University of California at Berkeley Electrical Engineering and Computer Science. - PowerPoint PPT Presentation
Citation preview
Ivy – A Sensor Network Infrastructure for the College of Engineering
ICM interface
A sensor network, that like ivy, spreads through the environment and links leaves to the root
Jaein Jeong, Lance Doherty and Kris PisterUniversity of California at Berkeley
Electrical Engineering and Computer ScienceLance DohertyJaein Jeong
Project Goals• Research infrastructure of networked sensors
• A lifetime of several months on 1 lithium battery or 2 AA batteries
• Support multiple applications simultaneously
Wireless ICM sensor• ICM (Indoor Climate Monitoring) sensor box
–Measures air speed, ambient / radiant temperature and is made by Professor Ed Arens group.
–Restricted monitoring capability due to the limited memory capacity and lack of constant connection to the host machine.
Sensor calibration• Rationale for Calibration
–Mapping ADC readings to meaningful number.
–ADC variation:Each mote and channel measures the same input voltage with some variance (Fig. 1).
–Non-linearity of temperature – voltage reading: Difficult to fit a voltage reading to the temperature with a single formula (Fig. 2).
• An ICM interface converts
–One anemometer reading(0 – 5V) to voltage input(at most 3.3 V).
–Three thermistor readings (58K to 18KΩ for 10 – 37°C) to voltage inputs.
–For a temperature sensor, two temperature range can be selected (10 – 40°C or18 – 30°C) as a trade-off of long range and accuracy.
• Voltage outputs from ICM interface are fed to a mote as ADC inputs.
Discussion and Future Works• Deployment for environment monitoring
–Plan to set up the 10 – 40 wireless ICM sensors to monitor the campus environment with Professor Ed Arens group.
An ICM sensor box
Thermistor 2(Radiant temp.)
Thermistor 1(Ambient temp.)
Anemometer(air speed)
ICM interface
•Wireless ICM
–We made an ICM interface board to bridge an ICM sensor box and a mica2dot mote.
–Will provide online monitoring and large storage capability.
R3
10KANEMOMETERR415K
VDD
-+
U4OPAMP
3
2
6
74
+
-
Anemometer Interface
ICM interface
VDD
THERMISTOR 1
R220K
R18
10K
C9
0.1UF
ADC_TEMP1
U3
2
310
1
9 56
8
7
4
V2V1I1I2
V+
V+
EN
AB
LE
VO
IOGN
D
R110K
C6
C FILTER
R1647K
R19
10K
VDD
J41
23
R1791K
R1527K
VDD
C50.1UF
INSTRUMENTATIONAMPLIFIER (INA330)
JUM-PER
Thermistor interface
0.00
0.50
1.00
1.50
2.00
2.50
3.00
5 10 15 20 25 30 35 40 45Temperature (°C)
Outp
ut
volt
age (
V)
10 – 40 °C18 – 30 °C
0.00
0.50
1.00
1.50
2.00
2.50
3.00
5 10 15 20 25 30 35 40 45Temperature (°C)
Outp
ut
volt
age (
V)
10 – 40 °C18 – 30 °C
Fig 1. Temperature readingfrom ICM interface
Fig. 2 Variation in ADC reading
• Two stage calibration
–We used two stage calibration:ADC => Vol => Air Speed / Temp.
–Allows using motes / interface interchangeably.
• ADC calibration
–Individually measured for each mote / channel.
–Measured ADC reading for range 0.3 – 3.0V with interval 0.3V (Fig. 3).
–Converts a given ADC reading to voltage by linear interpolation.
• Temperature calibration
–Measured the voltage reading for range 10 – 40 °C with interval 1°C. A temperature chamber was used to set the temperature (Fig. 4).
–Linearly interpolates voltage to temperature.
Thermistor
Fig. 4 Temperature Chamber
Fig. 3 ADC / TemperatureReader Application
–The examples:Building monitoring for critical environmentComfort field study.
Recommended