3. This webinar will be available afterwards at
www.designworldonline.com & email
Q&A at the end of the presentation
Hashtag for this webinar: #DWwebinar
Before We Start
4. Moderator Presenters
Randy Frank
Design World
Dr. Rolf Weber
IR Products, OSRAM
Opto Semiconductors
Mike Stanley
Freescale
Semiconductor
John Gammel
Sensor products,
Silicon Labs
6. 6
Common applications for relative humidity (RH) and temperature sensors
Overview of Silicon Labs’ RH and temperature sensors
Temperature effect on humidity
Solder sensitivity
Dust and liquid protection
Dealing with multiple devices on the I2C bus
Development tools
Agenda
7. 7
Humidity Sensor Applications
Remote Monitoring
• Windshield
Defogging
• Automobile
Climate Control
• Manufacturing
Environmental
Monitoring
• Compressed Air
Systems
• Asset Tracking
• Food and
Pharmaceutical
Storage
• Telecom Cabinets
and Datacenters
• Cellular Base
Stations
• HVAC/R
Thermostats and
Smoke Alarms
• Consumer
Weather Stations
• Wireless Sensor
Nodes
• Cellular Phone
and Accessories
• Respiratory
Therapy
• CPAP Machines
• Ventilators
Remote Monitoring
Home Automation
and Consumer
Devices
Automotive and
Industrial
Equipment
Healthcare
8. 8
• Negligible BOM cost
• Small 3x3 mm size
• SMT compatible
• Highest reliability
• Filter cover protects
against contamination
• High cost
• Large size
• Not SMT-compatible
• Low reliability
• Risk of
contamination
• Large BOM
• User calibration
• Not SMT-compatible
• Low reliability
• Risk of contamination
Si70xx vs. Legacy RH & Temperature Sensor
Solutions
Manufacturing Cost
and Complexity
Discretes (R/C)
MCMs and
Hybrid Modules
Si701x/2x
Monolithic ICs
Si701x/2x RH & temperature sensors
reduce cost and complexity, and improve
ease of use vs. legacy solutions
Time
9. 9
Introducing Si701x/2x Relative Humidity Sensors
High-precision relative humidity & temperature sensors offer unmatched ease of use
Accurate sensing
Full factory calibration and internal compensation
+/-3% RH / ±0.4°C max accuracy
Industry’s lowest power consumption
2.2 µW @ 3.3 V, 8-bit, 1 sample/second
Si701x/2x feature set provides unmatched ease of use
Unique, optional low-profile protective cover
Industry-standard PCB footprint and software interface
Support for 2-zone temperature sensor (Si7013)
Standard CMOS fab process ensures high-volume production capacity and high reliability
10. 10
Si701x/2x RH Sensor Family Overview
Higher accuracy and lower power than
Silicon Labs’ first-generation Si7005 sensor
Extended -40 to +125 °C temperature range
AEC-Q100 automotive qualified
Optional cover/filter available for all devices
Shown with
optional Cover/Filter
Part No.(s) Package
Typical
Accuracy
Max
Accuracy
Features
Si7013
3 x 3 mm
DFN-10
±2% RH
±0.3°C
±3% RH
±0.4°C
High precision RH and 2-zone
temperature sensor with I2C interface
Si7021
3 x 3 mm
DFN-6
±2% RH
±0.3°C
±3% RH
±0.4°C
High precision RH/T sensor with I2C
interface. Industry-standard PCB
footprint and software interface
Si7020
3 x 3 mm
DFN-6
±3% RH
±0.3°C
±4% RH
±0.4°C
Compact RH/T sensor with I2C
interface. Industry-standard PCB
footprint and software interface
11. 11
The “rule of thumb” for how temperature affects humidity is at 100% humidity 1°C of heating
will reduce humidity by 5%
This decreases linearly to zero as RH reduces
For accurate reading of humidity level the sensor must
be placed well away from any heat sources
If the amount of heating is known, it is possible to compensate
A thermistor near the heat source can be used to determine the
amount of heating and aid in the compensation
The Si7013 two-zone temperature sensor can be used to digitize
and linearize the thermistor voltage
In some applications, such as window fog sensing
dew point is of more interest than relative humidity
Dew point is the temperature at which condensation occurs for a given
air temperature and relative humidity
Dew point is not affected by heating
Temperature Effect on Relative Humidity
1 °C
5%RH
12. 12
Many IC type sensors are susceptible to shift in readings in soldering
This is particularly true for all humidity sensors (not just Silicon Labs)
Solder flux can contaminate the sensor
Excessive heat will cause shifts in readings
The optional protective cover for Si7013/20/21
sensors is solder compatible and provides
protection against contaminates during
soldering as well as after soldering
Use industry standard solder reflow profile
260 °C maximum
Do not use solder flux and use “no clean solder”
Cleaning in an ultrasonic alcohol bath will contaminate the sensor
Do no use hot air rework tools directed at the sensor
Limit solder touch up or hand soldering to 5 seconds per lead
Rework with new parts
Solder Sensitivity
13. 13
All humidity sensors are sensitive to dust and liquids and must be protected
A membrane that will allow water vapor to pass but will block liquids and dust is
recommended
Generally, these type of membranes are made of expanded Polytetrafluoroethylene
(ePTFE) and are available from several manufacturers
Polytetrafluoroethylene is known by the brand name Teflon
The best know type of ePTFE is Gore-Tex
The ePTFE cover available for Si7013/20/21 sensors is
solder compatible and factory applied
IP67 for dust and moisture resistance
Blocks liquid water to 2.7bar (39 PSI)
Oleophobicity (oil resistance) rating of 7
ePTFE barriers do not protect against chemical vapors
Use low volatile organic compounds (VOC) for other materials used in PCB assembly such as
under fill and conformal coating
Avoid cleaning agents such as alcohol or ammonia
Dust and Liquid Protection
Optional
Cover/Filter
14. 14
The Si7013/20/21 family and many other standard sensors have the option of “no hold” or
“hold” mode commands
Hold mode commands are more convenient because the device will hold the I2C bus (clock held low)
until the conversion is complete
This avoids having to set a timer or poll for conversion complete, but it does hold the bus for the
conversion time (typically 10 msec)
If the no-hold command is used, then the bus is not held and the device will not ACK until data is ready
Most sensors have a fixed I2C address so you cannot put more than one device of the same
type on the bus
Some RH sensors such as the Si7013 have a pin-programmed address
For larger numbers of devices of the same type, switch the I2C bus
The I2C bus is bidirectional on both SDA and SCL so a digital gate generally will not work; in this case
use an analog switch
If no hold mode commands are used and care is taken not to use a high-bus speed, clock stretching is
avoided and SCL can be digitally switched
In either case, be careful to leave SCL high when the device is not addressed
Multiple Devices on the I2C bus
15. 15
Si701x/2x EVBs and Development Kits
Si7013USB-DONGLE
• USB Dongle with Si7013
• “Postage stamp” boards for
Si7013, Si7020, Si7021
Si7013EVB-UDP
Si7013EVB-UDP-F960 (8-bit)
Si7013EVB-UDP-M3L1 (32-bit)
• UDP port header card
• 8-bit MCU development kit
• 32-bit MCU development kit
P/N Description
Si7013USB-DONGLE
General-purpose evaluation platform for “plug
and measure” evaluation of Si7013, Si7020 and
Si7021
SENSOR-EXP-EVB
Sensor expansion card for EFM32 Zero Gecko MCU
Starter Kit
Si7013EVB-UDP
UDP port header card for Silicon Labs MCU
development boards
Si7013EVB-UDP-F960 (8-bit)
Si7013EVB-UDP-M3L1 (32-
bit)
Si7013 UDP port header card + MCU development
kit
Si701x/2x General-Purpose EVB
SENSOR-EXP-EVB
• Sensor expansion card for
Zero Gecko MCU Starter Kit
16. 16
Si701x/2x Collateral and Software
Collateral
Si7013, Si7020 and Si7021 data sheets
AN607: Si70xx Humidity Sensor Designer’s Guide
Software
For Si7013USB-DONGLE:
• Evaluation software GUI
• USB drivers and source code
For Si7013EVB-UDP and MCU development kits:
• Demonstration software and source code
• Data logger application, GUI and source code
Android driver and demonstration app
Linux driver (Lm-sensors framework)
All Si701x/2x collateral and software is available at
http://www.silabs.com/products/sensors/humidity-
sensors/
18. External Use
TM
Layered Intelligence and the
Internet of Things
Design World Web Event
M a y 2 0 1 4
Michael Stanley
Manager, Algorithm Development
Freescale Sensor Solutions Division
20. TM
External Use | 20
Topics
• Condition-Based Maintenance (CBM)
• Condition-Based Monitoring
• Prognostics and Health Management (PHM) systems
• Machine Monitoring
• Predictive Maintenance
All mean essentially the same thing, which forms the basis for a
• mature industry, that was
• doing IoT before there was an IoT
Lowered costs in sensors and communications imply that CBM techniques may be
poised to extend into new areas – IF we can simplify the software side of things.
21. TM
External Use | 21
figure source; http://en.wikipedia.org/wiki/File:Centrifugal_Pump-mod.jpg
This machine includes:
• rotating motor
• centrifugal pump
• linkage between the two
Each is subject to its own array
of problems. These might
include:
• Bearing failures
• load imbalance
• shaft misalignment
• looseness
• gearbox faults
• drive belts
• resonance
22. TM
External Use | 22
TangentialAxial
Radial
Aligned
Angular misalignment
causes axial vibration at
1X running frequency
Parallel misalignment
causes radial vibration at
2X running frequency
Shaft Misalignment
23. TM
External Use | 23
Pd
B
d
Pd = pitch diameter
Bd = ball diameter
Nb = number of balls
S = speed (revolutions/sec
= contact angle
BSF = Ball Spin Frequency
BPFO= Ball Pass Frequency of Outer Trace
BPFI = Ball Pass Frequency of Inner Trace
Bearing faults have specific
frequency signatures
Defect signals may be swamped by
other noise in the system, in which case
enveloping or wavelet techniques may
be used to extract the signature.
For ball defects:
BSF = ½ (Pd/Bd) x S x [1 – (Bd/Pd x cos)2]
For outer trace defects:
BPFO = ½ Nb x S x [1 – (Bd/Pd x cos)]
For inner trace defects:
BPFI = ½ Nb x S x [1 + (Bd/Pd x cos)]
24. TM
External Use | 24 24
http://commons.wikimedia.org/wiki/File:NonSynchronousGearBoxSF.jpg
gear mesh speed = shaft speed X # of teeth
So = Si X Ti/To
where:
Ti = number of input teeth
To = number of output teeth
Si = input speed
So = output speed
Gears also have
specific frequency
signatures
25. TM
External Use | 25
Courtesy of Volvo Construction Equipment
(mages.volvoce.com)
Credit: IBM Research (http://www-
03.ibm.com/press/uk/en/photo/43250.wss)
Predictive
maintenance is a
must when you
cannot afford
downtime.
26. TM
External Use | 26
CBM
Breakdown Condition based
maintenance
diagnostics prognosticswhat went wrong? includes estimation for remaining useful life
data driven
physics-based
require sufficient samples that were run to failure
must understand the physics of expected failure
progression and how to get parameters required for
the model
more mature
than
prognostics
statistical
machine learning
27. TM
External Use | 27
Maintenance Scenarios
maintenance
preparation
actual
maintenance
scheduled
maintenance
maintenance
preparation
continuous RUL
estimation
Fault Detection
Down Time
Down Time
Unscheduled Maintenance
Managed Maintenance
From “Major Challenges in Prognostics: Study on Benchmarking Prognostics Datasets” by Eker, Camci and Jennions
Notice that in the 2nd scenario, we can minimize inventory
and do prep work while still “line-up”
28. TM
External Use | 28
• General Electric
• Techenomics International
• Vibrotech reliability services
• Condition Monitoring Services Inc.
• Vikon
• STI Vibration Monitoring
• ALS Limited
• Fluke
• GeoSonics / Vibra-Tech
• Timken
• Vipac Engineers and Scientists Ltd.
• Wagner Equipment Co.
• KIM Gruppen
• Allied Reliability Group
• Tezzco Inc.
• Sterling SIHI BmbH
• Bentley Nevada Services
• Monition Limited
• ROZH
• GasTOPS Ltd.
• Critical Software
• Azima DLI
• Balmac Inc.
• Diagnostic Solutions
• Siemens
• Prosig
• Condition Analyzing Corporation
• Metso Corporation
• Dresser-Rand
• dB Prűftechnik
• KCF technologies
• Schenck USA
• Machine Monitoring Systems
There are lots of players in this field. Many are service companies.
29. TM
External Use | 29
ISO 13374 Provides a Standard Architecture
for Condition Monitoring & Diagnostics
Sensor / Transducer / Manual Entry
Data Acquisition (DA)
Data Manipulation (DM)
State Detection (SD)
Health Assessment (HA)
Prognostic Assessment
(PA)
Advisory Generation (AG)
External
systems,
data
archiving
and block
configurati
on
Technica
l
displays
and
informati
on
presenta
tion
DA Basically a “server of calibrated digitized
sensor data records”. Outputs include
digitized data, timestamps, data quality
indicators
DM Extracts features from digitized sensor
data. Examples: FFT, wavelet, virtual
sensor, filtered data, normalized data, etc.
SD Compares DA & DM outputs against
expected baselines / operational limits to
determine health indicators. Outputs
might include enumerated state values,
threshold alerts, rate of change alerts,
deviation severities, etc.
HA Determine the current health of the system
and diagnose fault conditions
PA Estimate remaining useful life
Predict faults / failures
Generate recommendations
AG Integrate outputs from all other blocks and
provide optimized recommendations,
courses of action, advisories, prioritized
operational & maintenance actions, etc.
30. TM
External Use | 30
Freescale is
developing collateral
designed to simplify
implementation of
condition monitoring
systems.
Data Acquisition (DA)
Data Manipulation (DM)
State Detection (SD)
Health Assessment (HA)
Prognostic Assessment (PA)
Advisory Generation (AG)
Sensor / Transducer / Manual Entry
Development Board Matlab
Choices include:
• Sensor Type
• Axis (X, Y, Z, temp, etc)
• Sample Rate
Feature Extraction choices
include:
• FFT
• Wavelets
• Entropy
• RMS noise
• peak value
• etc.
Use Freescale
supplied GUIs and
embedded apps to
experiment with data
capture and feature
selection, then utilize
Matlab machine
learning algorithms to
develop higher level
ISO 13374 functions.
31. TM
External Use | 31
In real time, the user
can change:
• Sensor
• Axis
• Window
• Filter
All FFT computations
are done on the sensor
board.
Data can be logged,
replayed, and
transferred to Matlab.
A similar tool for
Wavelet analysis is in
development.
Freescale Xtrinsic Vibration Monitoring
32. TM
External Use | 32
To
Learn
More
Organizations:
• Open Operations &
Maintenance Initiative
(http://www.openoandm.org)
• Machinery Information
Management Open System
Alliance
(http://www.mimosa.org)
• International Organization for
Standardization
(http://www.iso.org)
• Center for Intelligent
Maintenance Systems
(http://www.imscenter.net)
References:
1. “Commercialization of Prognostics Systems
Leveraging Commercial Off-The Shelf
Instrumentation, Analysis and Data Base
Technologies”, Preston Johnson
2. “Vibration Diagnostic Guide”, SKF Reliability
Systems
3. “Harris Shock and Vibration Handbook”, 6th
edition, Allan G. Piersol & Thomas L. Paez,
McGraw Hill
4. “A Review of PHM System’s Architectural
Frameworks”, Surya Kunch, Chaochao Chen
& Michael Pecht.
5. “Review of Vibration Analysis Methods for
Gearbox Diagnostics and Prognostics”,
Mitchell Lebold, et. al.
35. Why a packaged demo?
Challenges for proximity sensing:
Cross talk due to reflection from a cover glass
=> Demo with cover glass and light barrier is more realistic
Cross talk
36. PCB top view
SFH 7770 E6:
3 prox. channels and
ALS
SFH 4059 LEDs
Externally switched
SFH 4059S LED
for long range
SFH 7743
for application
selection
37. IR LEDs
Proximity sensing for consumer devices:
Small LEDs are essential
SFH 4640 / 4641 / 4441 SFH 4645 / 4646 / 4140 SFH 4046 SFH 4045N
43. Application Modes
0.00
20.00
40.00
60.00
80.00
100.00
120.00
0 50 100 150
Relativesignalstrength
Time in ms
Proximity signals 2 ms apart
Prox 1
Prox 2
• Two pulses 2 ms apart:
• One measurement every 10 ms
• Centroid time = Σ time * signal / Σ signal
• Prox 1: 61.16 ms
• Prox 2: 59.64 ms => Prox 2 before Prox 1
46. Demo Kit Content
Sensor demo
with Micro USB
jack
3 x AAA
batteries
Battery pack
with Micro USB
connector
USB cable
47. Getting Started
• Use the battery pack or USB cable to power the demo.
1a. Battery Pack
• Insert AAA batteries in the
battery pack
• Connect the battery pack to
the demo
• Switch on battery pack
2. Operating the demo
1b. USB Cable
• Connect the USB cable to
demo and a computer
• See: Software Installation and
Graphical User Interface
Indicator LED
layouts and
respective
hand motions
48. Software
Download and installation of the GUI and USB driver:
• http://ledlight.osram-os.com/matchboxdemo
Source code:
• LabVIEW VI available on request
• Demo board C Code available on request
• Contact: rolf.weber@osram-os.com
49. Questions?
Randy Frank
Design World
r.frank@ieee.org
Dr. Rolf Weber
IR Products, OSRAM Opto Semiconductors
Rolf.Weber@osram-os.com
Mike Stanley
Freescale Semiconductor
Mike.Stanley@freescale.com
John Gammel
Sensor products, Silicon Labs
john.gammel@silabs.com
50. Thank You
This webinar will be available at
designworldonline.com & email
Tweet with hashtag #DWwebinar
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