PlaceLab “Intensive Activity” Test Dataset 1 (PLIA1)

 

Please read the PlaceLab Data overview document before continuing.

 

Note: We have substantially changed the format used for storing PlaceLab data. We are leaving this dataset online because some researchers have used it. However, those new too the PlaceLab should select a more recent dataset to familiarize themselves with the data and facility capabilities. 

 

Overview  of PLIA1

 

This sample PlaceLab dataset was recorded on Friday March 4, 2005 from 9 AM to 12 noon with a volunteer from our research team who was familiar with the PlaceLab, but not a creator of the core technical infrastructure.

 

The researcher was asked to perform a set of common household activities during the four-hour period that included the following: preparing two recipes, doing a load of dishes, cleaning the kitchen, doing at least two loads of laundry, making the bed, and light cleaning around the apartment. The volunteer determined the sequence, pace, and concurrency of these activities and also integrated additional household tasks. Our intent was to have a short test dataset of a manageable size that could be easily placed on the web without concerns about anonymity. We wanted this test dataset, however, to show a variety of activity types and activate as many sensors as possible, but in a natural way. In addition to the activities above, the researcher searches for items, struggles to use an appliance, talks on the phone, answers email, and performs other everyday tasks. The researcher wore two mobile accelerometers (one on the left thigh and the other on the right wrist) and a Polar M32 wireless heart rate monitor. The mobile sensors are called MITes and will be described in a publication available shortly.

 

The dataset includes four hours of fully annotated video. The annotation was done using ProCoderDV, a professional annotation application. All four hours were annotated with behavior, using descriptors for body posture, type of activity, location, and social context. The annotation ontology is described in more detail later. Additionally, one hour was annotated with all instances of interaction with objects or furnishings that, according to raters, should have produced certain switch or motion-based sensor activations.

 

The format of this dataset is consistent with those used for other data collection periods, although the exact number and position of sensors may change.

 

Purpose

 

This dataset is intended primarily as a sample that researchers can explore in order to familiarize themselves with the type of data the PlaceLab is capable of generating. Researchers seriously interested in using PlaceLab datasets, including those from non-researcher volunteers staying in the facility for extended time periods, should contact us. The PlaceLab can be reconfigured to collect other types of sensor data as well.

 

IMPORTANT! More recent datasets have higher quality data and the formats have changed. For example, the portable wireless sensors have been dramatically improved since this sample dataset was collected.

 

Images from this document or raw data from this dataset is not intended for use in news articles or other publications without the explicit consent of a PlaceLab researcher.

 

Directory Structure

 

Size: 4.11 GB total (258 MB without Video and Audio)

 

The root directory of the data is named PlaceLab-03-04-2005, indicating the start date of the data collection. We refer to this as [root] below. This directory contains four subdirectories:

 

With the sensorData and videoData directories, the data is structured by date. In this case, all data was collected on a single day, so the subdirectory is 04Mar2005. Below that directory is one directory for every hour of the day in military time (i.e., 09 – 12 for this dataset). More detail on each data type follows below.

 

The data can be found here: http://architecture.mit.edu/house_n/data/PlaceLab/PlaceLab-03-04-2005. Note that each of the directories is zipped for convenient downloading except for the (extremely large) videoData directory.

 

PlaceLab Sensor Data Overview

 

All raw sensor data except video and audio is located in the [root]/sensorData directory.  In this dataset, there are 11 different types of sensors whose data is recorded. Listed by type of sensor, they are:

 

Type of Sensor

Description

Filename

Wired switch

Detects on/off and open/closed events, such as doors being opened/closed and knobs being turned using switches built into the infrastructure.

1WireSwitch.dat

Wired humidity

Measures relative humidity in various locations using a wired sensor.

1WireHumidity.dat

Wired pressure

Measures barometric pressure in the living room using a wired sensor.

1WirePressure.dat

Wired light

Measures degree of illumination in several areas (especially those without cameras) in order to detect if lights are on.

1WireIllumination.dat

Wired temperature

Measures ambient temperature at floor and ceiling around the apartment.

1WireTemperature.dat

Wired gas

Measures amount of gas flow of the hot water heater and the stovetop burners.

1WireGasFlow.dat

Wired current

Measures amount of current flow in 43 electrical circuits around the apartment.

1WireCurrent.dat

Wired water

Measures amount of water flow for hot or cold faucets and toilets.

1WireWaterFlow.dat

Wireless static

Measures movement of the object to which it is attached and wirelessly sends data to receivers scattered around the apartment.

MITesStatic.dat and MITesStaticAlive.dat (stores “alive” pings received from sensors to verify they are active even when not moving).

Wireless heart rate

Measures heart rate of the person wearing a Polar wireless heart rate chest strap.

MITesHeartRate.bin

Wireless on-body

Measures limb movement of the person wearing the sensor using custom, wireless 3-axis 0-10G accelerometers. Receivers scattered around the apartment collect data.

MITesOnBodyPL16.bin

MITesOnBodyPL17.bin

MITesOnBodyPL18.bin

MITesOnBodyPL19.bin

MITesOnBodyPL20.bin

MITesOnBodyPL21.bin

Areas of visual motion from cameras

Indicates which of 18 camera views were selected (and saved as one of 4 quadrants) at any given moment. Also indicates which audio stream is selected. Can be useful for determining location of a PlaceLab resident.

VideoAudioActive.dat

Areas of visual motion from cameras

Indicates the amount of motion detected in all 18 camera views. Can be useful for determining location of a PlaceLab resident.

VideoDifferencer.dat

 

Warnings – any unusual data received by the data archiving computer (e.g. due to a faulty sensor). Used by PlaceLab team for debugging.

Warnings.dat and Unknown.dat

 

Audio and visual data is also saved and located in the [root]/sensorData directory.

 

All sensor data (with the exception of video, heart rate, and on-body data, discussed more below) is stored as text in .dat files with a separate file for each type of sensor.  Each file represents an hour of sensor activity.  Each line of text within one of these files contains information about the sensor state at the time indicated by a time stamp.

 

Wired sensors are directly connected to a TINI board in one of the cabinet units in the PlaceLab.  Refer to [link to paper] for more information about how they are wired.  Data from these wired sensors is stored in files named 1Wire*.dat, where * is the type of sensor.  The format is as follows:

 

Timestamp(hr:min:s:ms)   Type_number   ID_number   Value   IP_address

 

The first value is the time at which the information was recorded.  The second value indicates the sensor type.  The third value is the ID number of the particular sensor that sent the data at the given time – each sensor has a unique ID.  The Value field contains a measurement that is in units specific to what the sensor is meant to detect.  The final value on each row represents the last byte of the four byte (32 bit) IP address of TINI board to which the sensor is connected. TINI boards are scattered throughout the apartment. Figure 1 below shows the location of each TINI board.

Figure 1: TINI Board Locations with Identifiers

 

 

Wired Switches

 

The switches are sensors that allow communication through the standard Dallas Semiconductor 1-wire protocol. Specifically, the switches use a DS2406P Dual Addressable Switch plus 1kb Memory IC and were obtained from MAXIM for $4.65(US) apiece.  Documentation for the sensors and ordering information can be found on the MAXIM website [http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2907]. The sensors detect whether a movable object, such as a cabinet door or drawer, is in an open or closed state. Since the IC is dual addressable two switches can be attached to one sensor board. They send an integer value of zero or two for open, and a value of one or three for closed, depending to which of the two sensor board locations a switch is wired.

 

There were 85 switches (53 different sensor boards) active during this data collection period.  The location of each switch sensor during this experiment is indicated on Figure 2. The description of each sensor can be found in the sensor ID file ([root]\sensorLocationInformation\sensorlist.csv).  For example, in that file the row,

 

0900000022A09C12Z, 1, 1WireSwitch, 69, Living room window right, 3, 95

 

indicates that switch sensor with ID 0900000022A09C12Z is located at pixel position (3, 95) on the PlaceLab plan diagram in [root]\sensorLocations\plan.jpg.  This sensor is on the right side living room window.  The sensor ID can be looked up on the images in [root]\sensorLocations\ims\. To locate the image that shows the sensor of interest, use the ImageMap.csv file located in the [root]\sensorLocations\ims\ directory.

 

Figure 2: Switch Sensor Locations

 

  Switch sensors are sampled at different frequencies based on if there are other sensor types connected to the TINI board. If no other sensor type (e.g. only switch sensors) are connected to a TINI board then the sampling frequency is approximately 1.1 seconds. This frequency is approximate due to variance that can result from the number of different switch sensor boards connected to a specific TINI board. If other sensors are connected to the same TINI board, then the switch sensor sampling frequency depends on the number of other sensors and the individual sampling frequencies of these other sensors. The non-switch sensors are sampled at a slower sampling rate in order to avoid causing delays in the sampling of the switch sensors. Thus the sampling strategy is as follows. Once a minute all sensors attached to a TINI board are sampled. If the sampling of all devices attached to the TINI board (including switch sensors) takes less than 60 seconds then in the remaining seconds of the minute cycle only the switch sensors are polled (see Figure 3). Future upgrades to the PlaceLab may allow for a higher sampling rate.

Figure 3: Switch Sensor Sampling Strategy

 

The switch data is stored in [root]\sensorData\[date]\[hour]\1WireSwitch.dat. Data in each 1WireSwitch.dat file looks like,

 

            09:00:06:921 1 A4000000223AA112 3.0 62

            09:00:07:250 1 1500000022CFF412 2.0 66

            09:00:18:046 1 350000002233C912 3.0 66

            .

            .

            .

            09:01:33:843 1 3700000022B4B912 3.0 52

            09:01:34:921 1 AA00000022B46A12 0.0 52

            09:01:37:531 1 3700000022B4B912 2.0 52

 

This data type follows the standard 1-wire sensor format described above: Timestamp(hr:min:s:ms),  sensor type_number (1 for switches), ID_number of 1-wire sensor, value returned by sensor, and last two digits of the IP address of the computer (i.e., the TINI board) that sent the data.  This example is found in the [root]\sensorData\09\1WireSwitch.dat file.  Therefore, the first line of the example indicates that switch sensor 3700000022B4B912 located on the front entrance door (see Figure 2) returned a value of 3.0 on March 4, 2005 at 9:01 AM (and 33.843 seconds), indicating the door was opened.  The next time data from that same sensor was recorded was at 9:01 AM (and 37.531 seconds) with a value of 2.0, indicating the door was closed.

 

Humidity Sensors

 

The humidity sensors are sensors that allow communication through the standard Dallas Semiconductor 1-wire protocol. Specifically, the humidity sensors use a Honeywell HIH-3610, a popular relative humidity to DC voltage sensor. The Honeywell HIH-3610-002 were ordered from Arrow Electronics [http://www.arrow.com/] for $23.72(US) apiece. Documentation for the Honeywell HIH-3610 can be found on the Honeywell website [http://content.honeywell.com/sensing/prodinfo/humiditymoisture/009012_2.pdf]. Additionally, the humidity sensors use a DS2438Z Smart Battery Monitor IC and were obtained from MAXIM for $1.97(US) apiece.  Documentation for the sensors and ordering information can be found on the MAXIM website [http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2919]. The sensors measure humidity in RH (relative humidity) between 0% and 100% with a maximum precision of approximately 1/3 %. 

 

There were 10 humidity sensors active during this data collection period. The location of each humidity sensor during this experiment is indicated on Figure 4. The description of each sensor can be found in the sensor ID file ([root]\sensorLocations\sensorlist.csv).  For example, in that file the row,

 

0D0000003F607126, 2, 1WireHumidity, 69, Living room bookshelf attic, 44, 40

 

indicates that humidity sensor with ID 0D0000003F607126 is located at position 44, 40 on the PlaceLab plan diagram in [root]\sensorLocations\plan.jpg.  This sensor is located at the top of the bookshelf to the right of the living room window.  The sensor ID can be looked up on the images in [root]\sensorLocations\ims\. To locate the image that shows the sensor of interest, use the ImageMap.csv file located in the [root]\sensorLocations\ims\ directory.

 

Figure 4: Humidity Sensor Locations

 

Humidity data is stored in [root]\sensorData\[date]\[hour]\1WireHumidity.dat.  The humidity sensors are sampled at approximately once per minute in this data set.  All analog 1-wire sensors are sampled infrequently to avoid causing delays in sampling of switch sensors.  The sampling rate can vary somewhat (in seconds) depending upon activations of other nearby sensors.  Future upgrades to the PlaceLab may allow for a higher sampling rate.

 

Data in each 1WireHumidity.dat file looks like,

 

09:00:06:093 2 120000004C002126 16.87749512483423 54

09:00:09:593 2 040000004C095D26 14.55548760372063 68

09:00:12:625 2 1E0000003F607F26 12.06580303329285 51

.

.

.

09:01:00:953 2 040000004C095D26 14.55646746086851 68

09:01:01:015 2 120000004C002126 16.87296477167182 54

09:01:02:796 2 1E0000003F607F26 11.99264929718915 51

 

This data type follows the standard 1-wire sensor format described above: Timestamp(hr:min:s:ms),  sensor type_number (2 for humidity), ID_number of 1-wire sensor, value returned by sensor, and last two digits of the IP address of the computer (i.e., the TINI board) that sent the data.  This example is found in the [root]\sensorData\04Mar2005\09\1WireHumidity.dat file.  Therefore, the first line of the example indicates that humidity sensor 040000004C095D26 located above the microwave (see Figure 4) returned a value of 14.55548760372063% RH on March 4, 2005 at 9:00 AM (and 9.593 seconds).  The next time data from that same sensor was recorded was at 9:01 AM (and 0.953 seconds) with a value of 14.55646746086851% RH. (Most of that precision is noise but shown here for clarity!)

 

Barometric Pressure Sensors

 

The barometric pressure sensors are sensors that allow communication through the standard Dallas Semiconductor 1-wire protocol. Specifically, the pressure sensors use a Motorola MPX4115A, an integrated silicon pressure sensor. The Motorola MPXA4115A6U-ND was ordered from Digikey [http://www.digikey.com/] for $17.57(US) apiece. Documentation for the MPX4115A can be found on the Digikey website [http://rocky.digikey.com/WebLib/Motorola/Web%20Data/MPX4115A,%20MPXA4115A%20SERIES.pdf]. Additionally, the pressure sensors use DS2438Z Smart Battery Monitor ICs that were obtained from MAXIM for $1.97(US) apiece.  Documentation for the sensors and ordering information can be found on the MAXIM website [http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2919]. The sensors measure barometric pressure in kiloPascals between 15 kPa and 115 kPa with a maximum precision of 1/ (4.59) kPa.

 

There was a single pressure sensor used during this experiment.  Its location in indicated on Figure 5. The description of each sensor can be found in the sensor ID file ([root]\sensorLocationInformation\ sensorlist.csv).  This sensor is located at the top of the bookshelf to the right of the living room window.

 

Figure 5: Pressure Sensor Location

 

Pressure data is stored in [root]\sensorData\[date]\[hour]\1WirePressure.dat.  The pressure sensor is sampled at approximately once per minute in this data set.  All analog 1-wire sensors are sampled infrequently to avoid causing delays in sampling of switch sensors.  The sampling rate can vary somewhat (in seconds) depending upon activations of other nearby sensors.  Future upgrades to the PlaceLab may allow for a higher sampling rate.

 

Data in each 1WirePressure.dat file looks like,

 

     09:00:49:953 3 4A0000004C097626 102.7777777777777 69

      09:01:44:906 3 4A0000004C097626 102.7777777777777 69

      .

      .

      .

      09:58:50:515 3 4A0000004C097626 102.7777777777777 69

      09:59:45:390 3 4A0000004C097626 102.7777777777777 69

 

This data type follows the standard 1-wire sensor format described above: Timestamp(hr:min:s:ms),  sensor type_number (3 for pressure), ID_number of 1-wire sensor, value returned by sensor, and last two digits of the IP address of the computer (i.e., the TINI board) that sent the data.  This example is found in the [root]\sensorData\04Mar2005\09\1WirePressure.dat file.  Therefore, the first line of the example indicates that the pressure sensor, with ID 040000004C095D26, returned a value of 102.7777777777777 on March 4, 2005 at 9:00 AM (and 49.953 seconds).  The next time data from that same sensor was recorded was at 9:01 AM (and 44.906 seconds) with the same value. As with many of the other sensors, most of the fractional precision shown here is  noise or results from division operations (e.g. when converting voltage to pressure).

 

Light Sensors

 

The light sensors are sensors that allow communication through the standard Dallas Semiconductor 1-wire protocol. Specifically, the light sensors use a Vishay silicon PIN photodiode (model# BPW34), high speed and high sensitive PIN photodiode in a miniature flat plastic package. The Vishay photodiode was ordered from Arrow Electronics [http://www.arrow.com/] for $0.57(US) apiece. Documentation for the Vishay photodiode can be found on the Vishay website [http http://www.vishay.com/docs/81521/81521.pdf]. Additionally, the light sensors use a DS2438Z Smart Battery Monitor IC and were obtained from MAXIM for $1.97(US) apiece.  Documentation for the sensors and ordering information can be found on the MAXIM website [http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2919]. The sensors measure irradiance (mW/cm2) in between [0.020 to 1.2].

 

There were 6 light sensors active during this data collection period placed in the following locations:

ID

Location

030000004BFDA026

Master bath ceiling light shelf above shower  facing mirror

150000004C1DAD26

Bedroom above wardrobe

5A0000004C0EA126

Bedroom above side closet

680000004C1DA126

Powder room above toilet facing mirror

D30000004C005226

Bedroom ceiling light shelf

F10000004C0B8B26

Living room television screen

 

 The location of each light sensor during this experiment is indicated on Figure 6. The description of each sensor can be found in the sensor ID file ([root]\sensorLocations\sensorlist.csv).  For example, in that file the row,

 

030000004BFDA026, 4, 1WireIllumination, 55, Master bath sink attic, 786, 224

 

indicates that light sensor with ID 030000004BFDA026 is located at position 786, 224 on the PlaceLab plan diagram in [root]\sensorLocations\plan.jpg.  This sensor is located near the ceiling above the sink in the master bathroom.  The sensor ID can be looked up on the images in [root]\sensorLocations\ims\. To locate the image that shows the sensor of interest, use the ImageMap.csv file located in the [root]\sensorLocations\ims\ directory.

 

Figure 6: Light Sensor Locations

 

Illumination data is stored in [root]\sensorData\[date]\[hour]\1Wireillumination.dat.  The light sensors are sampled at approximately once per minute in this data set.  All analog 1-wire sensors are sampled infrequently to avoid causing delays in sampling of switch sensors.  The sampling rate can vary somewhat (in seconds) depending upon activations of other nearby sensors.  Future upgrades to the PlaceLab may allow for a higher sampling rate.

 

Data in each 1WireIllumination.dat file looks like,

 

     09:00:00:359 4 680000004C1DA126 4.8828125 56

      09:00:03:968 4 5A0000004C0EA126 2.44140625 62

      09:00:06:921 4 F10000004C0B8B26 0.0 54

      .

      .

      .

      09:01:00:140 4 5A0000004C0EA126 2.44140625 62

      09:01:01:906 4 F10000004C0B8B26 -4.8828125 54

      09:01:02:484 4 030000004BFDA026 4.8828125 55

 

This data type follows the standard 1-wire sensor format described above: Timestamp(hr:min:s:ms),  sensor type_number (4 for light), ID_number of 1-wire sensor, value returned by sensor, and last two digits of the IP address of the computer (i.e., the TINI board) that sent the data.  This example is found in the [root]\ sensorData\04Mar2005\09\1WireHumidity.dat file.  Therefore, the first line of the example indicates that light sensor F10000004C0B8B26 located on the television screen in the living room (see Figure 6) returned a value of 0.0 on March 4, 2005 at 9:00 AM (and 6.921 seconds).  The next time data from that same sensor was recorded was at 9:01 AM (and 1.906 seconds) with a value of –4.8828125. It should be noted that the negative value is a result of near complete dark light conditions and the photodiodes inaccuracy at these very low light conditions.

 

 

Temperature Sensors

 

The temperature sensors are sensors that allow communication through the standard Dallas Semiconductor 1-wire protocol. The temperature sensor used is the DS18S20 and was obtained from MAXIM for $2.57(US) apiece.  Documentation for the sensors and ordering information can be found on the MAXIM website [http://pdfserv.maxim-ic.com/en/ds/DS18S20.pdf]. The sensors measure temperature in degrees Celsius from -55 to +125 with a maximum precision of  ±0.5 degree in the range –10 to +85 Celsius.

 

 

There were 36 temperature sensors active during this data collection period.  Floor sensors are usually located 25 centimeters off the ground and “ceiling” sensors are normally located 200 centimeters from the ground (which is usually 22 centimeters from the ceiling). The location of each temperature sensor during this experiment is indicated on Figure7. The description of each sensor can be found in the sensor ID file ([root]\sensorLocations\sensorlist.csv).  For example, in that file the row,

 

750008003AFC4310, 5, 1WireTemperature, 55, Master bath over sink left upper, 786, 212

 

indicates that temperature sensor with ID 750008003AFC4310 is located at position 786, 212 on the PlaceLab plan diagram in [root]\sensorLocations\plan.jpg.  This sensor is on the ceiling as indicated by the description of the cabinet (“over sink left upper” is a high cabinet).  The sensor ID can be looked up on the images in [root]\sensorLocations\ims\. To locate the image that shows the sensor of interest, use the ImageMap.csv file located in the [root]\sensorLocations\ims\ directory.

 

Figure 7: Temperature Sensor Locations

 

Temperature data is stored in [root]\sensorData\[date]\[hour]\1WireTemperature.dat.  Temperature sensors are sampled at approximately 1 per min in this data set.  All analog 1-wire sensors are sampled infrequently to avoid causing delays in sampling of switch sensors.  The sampling rate can vary somewhat (in seconds) depending upon activations of other nearby sensors.  Future upgrades to the PlaceLab may allow for a higher sampling rate.

 

Data in each 1WireTemperature.dat file looks like,

 

          09:00:12:890 5 750008003AFC4310 21.5 55

            09:00:13:828 5 EA0008003AE29410 18.5 63

            09:00:15:265 5 1E0008003AD70A10 25.0 63

            .

            .

            .

            09:01:01:093 5 9E0008003AFF6D10 19.5 66

            09:01:01:171 5 750008003AFC4310 21.5 55

            09:01:10:515 5 EA0008003AE29410 18.5 63

 

This data type follows the standard 1-wire sensor format described above: Timestamp(hr:min:s:ms),  sensor type_number (5 for temperature), ID_number of 1-wire sensor, value returned by sensor, and last two digits of the IP address of the computer (i.e., the TINI board) that sent the data.  This example is found in the [root]\sensorData\04Mar2005\09\1WireTemperature.dat file.  Therefore, the first line of the example indicates that temperature sensor 750008003AFC4310 located in the ceiling above the sink in the master bathroom (see Figure 7) returned a value of 21.5 degrees C on May 4, 2005 at 9:00 AM and (12.890 seconds).  The next time data from that same sensor was recorded was at 9:01 AM and (1.171 seconds) with a value of 21.5 degrees C.

 

As one might expect, the temperature values at the floor are typically lower than temperature readings at the ceiling.  Some sensors are located near cool drafts (e.g. near the glass door) and tend to output lower temperatures.

 

Gas Flow Sensors

 

The gas flow sensors are mass flow meters and were obtained from Omega (Model# FMA 1700) at [~550USD].  Documentation for the sensors can be found [http://omega.com/manuals/manualpdf/M1680.pdf].  The sensors measure gas flow in gallons per minute between 0.5 and 5 Gallons Per Minute (GPM) with a maximum precision of ±1.5% full scale. The output of the sensor is a linear voltage between 0-5VCD for full output scale and the response time is 800ms. The sensor is powered by a +12V power supply.

 

There was a single gas flow sensor used during this experiment.  Its location in indicated on Figure 8. The description of each sensor can be found in the sensor ID file ([root]\sensorLocationInformation\ sensorlist.csv).  It is attached to the gas line leading to the kitchen stove.

 

Figure 8: Gas Sensor Location

 

Gas flow data is stored in [root]\sensorData\[date]\[hour]\1WireGasFlow.dat.  The gas flow sensor is sampled at approximately once per minute in this data set.  All analog 1-wire sensors are sampled infrequently to avoid causing delays in sampling of switch sensors.  The sampling rate can vary somewhat (in seconds) depending upon activations of other nearby sensors.  Future upgrades to the PlaceLab may allow for a higher sampling rate.

 

Data in each 1WireGasFlow.dat file looks like,

 

     09:00:08:250 6 5B00000053C01E26 0.05 68

      09:00:59:609 6 5B00000053C01E26 0.05 68

      .

      .

.

      09:28:56:750 6 5B00000053C01E26 0.05 68

      09:29:47:515 6 5B00000053C01E26 0.99 68

 

This data type follows the standard 1-wire sensor format described above: Timestamp(hr:min:s:ms),  sensor type_number (6 for gas), ID_number of 1-wire sensor, value returned by sensor, and last two digits of the IP address of the computer (i.e., the TINI board) that sent the data.  This example is found in the [root]\sensorData\04Mar2005\09\1WireGasFlow.dat file.  Therefore, the first line of the example indicates that the gas flow sensor, with ID 5B00000053C01E26, associated with the kitchen stove, returned a value of 0.05 GPM on March 4, 2005 at 9:00 AM (and 8.250 seconds).  The next time data from that same sensor was recorded was at 9:00 AM (and 59.609 seconds) with the same value.

 

Current Sensors

 

The current sensors are split-core current transformers and were obtained from CR Magnetics (Model# CR3110-3000) at $12.25 per device.  Documentation for the sensors can be found [http://www.crmagnetics.com/pdf/3110.pdf].  The sensor is attached to a generic 1-wire sensor board using the DS2438Z Smart Battery Monitor as an ADC. The sensors board measure current flow in amperes between 0 and 20 amps with a maximum precision of  ±7% full scale. The sensor board generates a linear output voltage from 0-10.23VDC for a full output scale. The sensor board is powered by a +12V power supply.

 

There were 37 current sensors active during this data collection period. All the current sensors are located in a utility box near the main circuit breaker in the apartment. The location of outlets and devices for each circuit is indicated on Figure 9 and can be found in the sensor ID file ([root]\sensorLocations\sensorlist.csv).  Note that the colors in Figure 9 are significant and indicate which outlets/devices are associated with which labels.

 

In the sensorList.csv file the row,

 

1A00000053B37626, 7, 1WireCurrent, 0, Living Room Lighting, 30, 520

 

indicates that current sensor with ID 1A00000053B37626 is located at position 30, 520 on the PlaceLab plan diagram in [root]\sensorLocations\plan.jpg.  This sensor is attached to the circuit associated with the living room lighting.  The sensor ID can be looked up on the images in [root]\sensorLocations\ims\. To locate the image that shows the sensor of interest, use the ImageMap.csv file located in the [root]\sensorLocations\ims\ directory.

 

 

Figure 9: Current Sensor Locations subdivided by light and power.

 

Current flow data is stored in [root]\sensorData\[date]\[hour]\1WireCurrent.dat.  The current sensors are sampled at approximately once per minute in this data set.  All analog 1-wire sensors are sampled infrequently to avoid causing delays in sampling of switch sensors.  The sampling rate can vary somewhat (in seconds) depending upon activations of other nearby sensors.  Future upgrades to the PlaceLab may allow for a higher sampling rate.

 

Data in each 1WireCurrent.dat file looks like,

 

     09:00:01:046 7 A600000054001D26 0.0 67

      09:00:02:203 7 D300000054005D26 3.42 67

      09:00:03:359 7 5400000053B35D26 0.0 67

      .

.

      .

      09:01:06:140 7 A600000054001D26 0.0 67

      09:01:07:015 7 D300000054005D26 0.62 67

      09:01:07:890 7 5400000053B35D26 0.0 67

 

This data type follows the standard 1-wire sensor format described above: Timestamp(hr:min:s:ms), sensor type_number (7 for current), ID_number of 1-wire sensor, value returned by sensor, and last two digits of the IP address of the computer (i.e., the TINI board) that sent the data.  This example is found in the [root]\ sensorData\04Mar2005\09\1WireCurrent.dat file.  Therefore, the first line of the example indicates that current sensor D300000054005D26 associated with the hot water heater located in the bedroom   (see Figure 9) returned a value of 3.42 amperes on March 4, 2005 at 9:00 AM (and 2.203 seconds).  The next time data from that same sensor was recorded was at 9:01 AM (and 7.015 seconds) with a value of 0.62 amperes.

 

 

Water Flow Sensors

 

Water flow sensors have been installed on hot and cold water supply lines at fixtures in the PlaceLab kitchen, laundry closet, powder room, and master bathroom. Paddle-wheel flow meters from Omega Engineering, Inc. (Model# FPR133) are used. Details on these meters can be found at http://www.omega.com/manuals/manualpdf/M1982_d.pdf. The model chosen measures water flow in gallons per minute between 0.5 and 5 gpm with an accuracy of +/- 7%.

 

There were 14 water flow sensors active during this data collection period. A flow sensor is located on each cold and hot water outlet. These are kitchen sink hot, kitchen sink cold, kitchen dishwasher, master bath sink hot, master bath sink cold, mater bath toilet, master bath shower hot, master bath shower cold, powder room sink hot, powder room sink cold, powder room toilet, clothes washer hot, clothes washer cold.. The location of each water flow sensor during this experiment is indicated on Figure 10. The description of each sensor can be found in the sensor ID file ([root]\sensorLocations\sensorlist.csv).  For example, refer to the following:

 

1300000053D19026, 8, 1WireWaterFlow, 0, Kitchen Sink Cold, 314, 101

 

This entry indicates that the sensor with ID 1300000053D19026 is of type ‘8’ (1WireWaterFlow). It is attached to an undesignated TINI board (i.e., 0), and is installed on the cold water supply to the kitchen sink. This sensor is located at position 314, 101 on the PlaceLab plan diagram in [root]\sensorLocations\plan.jpg.

 

Water flow data is stored in [root]\sensorData\[date]\[hour]\1WireWaterFlow.dat.  The water flow sensors are sampled approximately 5 times per minute in this data set.  All analog 1-wire sensors are sampled infrequently to avoid causing delays in sampling of switch sensors.  The sampling rate can vary somewhat depending upon activations of other nearby sensors.  Future upgrades to the PlaceLab may allow for a higher sampling rate.

 

 

Figure 10: Water Flow Locations

 

Data recorded from the water flow sensors follows the standard 1-wire sensor format described previously:

 

Timestamp(hr:min:s:ms)     Type_number     ID_number      Value      IP_address

 

Below is a sample of data from the WireWaterFlow.dat file for 9:00am on 4 March 2005:

 

     09:00:02:281 8 9A00000053D0E426 0.02 55

      09:00:03:984 8 7200000053D35C26 0.02 55

      .

      .

      .

      09:00:18:046 8 9A00000053D0E426 0.01 55

      09:00:19:625 8 7200000053D35C26 0.01 55

      09:00:20:796 8 5B00000053C56326 0.01 55

 

All entries in this file begin with a Timestamp indicating when the value was received by the data logger. Type_number ‘8’ designates a flow sensor and will not vary in this document. The 16-digit hexadecimal ID_number can be used to identify the location of this sensory using the [root]\sensorLocations\sensorlist.csv spreadsheet. To locate the image that shows the sensor of interest, use the ImageMap.csv file located in the [root]\sensorLocations\ims\ directory.

 

In the example shown here, the sensor (9A00000053D0E426) shown on the first line is located on the hot water pipe for the master bathroom sink. At the time of report, it returned a value of 0.02 GPM. The next time data from that same sensor reported (15.765 seconds later) it returned a value of 0.01 GPM.

 

One problem with using the flow sensors in the PlaceLab is that there is a tendency for the paddlewheels to flow backwards sometimes even when the water is on. This problem is due to a flow restrictor on all of the faucet nozzles and unequal pressure on the hot water and cold water lines. The backflow problem occurs when both the hot water and cold water for a single faucet are opened all the way or nearly all the way. Restriction of water flow as a result of the flow restrictor on the faucet nozzle causes pressure to build and water to backflow through the hot water line. The back flow is not substantial, but it causes the reading of the hot water flow to be at its minimum value event though the hot water is on. Incidentally, this reading is near accurate since the temperature of the water is cooler than if the hot and cold water flow were set equal for lower individual rates of flow.

 

 

Wireless Object Movement Sensors

 

The wireless object movement sensors (MITes) are sensors designed to be attached to any movable physical object. Fundamentally, MITes consist of one two-axis 2G accelerometer and an RF transceiver. A MITes is a simple sensor used to measure acceleration and broadcast a unique ID whenever a dynamic movement causes the measured acceleration to surpass a specified sensitivity threshold. The MITes have been dramatically improved since this dataset was collected.

 

There were 124 MITes sensors active during this data collection period.  The MITes are attached to a wide variety of movable objects throughout the PlaceLab. These objects include items such as cabinet and entry doors, drawers, chairs, toilet seat covers, couch cushions, soap dispensers, etc. The location of each MITes sensor during this experiment is indicated on Figure 11. The description of each sensor can be found in the sensor ID file ([root]\sensorLocations\sensorlist.csv).  For example, the following entry,

 

91, 11, MITesStatic, 0, kitchen - microwave door, 460, 130

 

indicates that MITes sensor with ID 91 is located at position (460,130) on the PlaceLab plan diagram in [root]\sensorLocations\plan.jpg.  As indicated this sensor has been placed on the door of the kitchen microwave. 

 

Figure 11: Static MITes Locations

 

The MITes sensor data is stored in [root]\sensorData\[date]\[hour]\MITesStatic.dat. 

 

The data transmitted by the individual MITes is collected by one or more MITes RF receivers located throughout the PlaceLab. In total there are six receivers placed throughout the PlaceLab to ensure maximum RF coverage. The following table lists the locations of the six receivers and the identifier of the PC to which each receiver is attached. 

 

 

 

Placelab Machine

Physical Location

Placelab 16 (PL16)

Kitchen island

Placelab 17 (PL17)

Living Room

Placelab 18 (PL18)

Bedroom

Placelab 19 (PL19)

Office

Placelab 20 (PL20)

Hallway Bathroom (Powder Room)

Placelab 21 (PL21)

Master Bathroom

 

Data in each MITesStatic.dat file looks like,

 

09:01:35:156 11 274 21 0 18.0

09:01:35:671 11 274 21 1 7.0

09:01:37:515 11 95 16 3 43.0

 

This data type follows the format:

Timestamp(hr:min:s:ms),  sensor type_number (11 for MITes), ID_number of sensor, last two digits of the IP address of the computer (i.e., the TINI board) that sent the data, resend ID, and the value at which the sensor was activated.  This example is found in the [root]\sensorData\04Mar2005\09\MITesStatic.dat file.  Therefore, the first line of the example indicates that MITes sensor 274 located on door to the master bedroom (see Figure 11) was activated with an acceleration value of 18.0 g on March 4, 2005 at 9:01 AM (and 35.156 seconds). This value represents the magnitude of the difference between the current acceleration value and a running average filter over the previous three acceleration samples.  This value is measured in units of g (also known as g-force or g-load). g is a non-SI unit of acceleration which is defined as 9.80665 m/(s*s), approximately the acceleration due to Earth’s gravitation. 

 

As can be seen in the previous table, each receiver is attached to a different processing machine (PC). The MITes data collection architecture is distributed by having an individual computer process the data for each receiver and then forward this data to a central routing machine (PL16). This central routing machine then forwards the pre-processed data on to a data recording machine (PL15). Figure 12 describes this architecture. This distribution is to allow for future complex, real-time processing of both the data being transmitted by the wireless object movement MITes and the higher resolution data being transmitted by the Mobil Accelerometer MITes and the Heart Rate MITes (see below) while not disrupting the collection of other sensor data such as the wired sensors, video, etc. Artifacts of this distributed architecture and the wireless point-to-point communication between the wireless MITes transmitter and the receiver lead to the need for some rudimentary pre-processing before the collected data is saved. The next few paragraphs present why this pre-processing is needed and how it is done.

 

Figure 12: MITes Receiver Architecture

 

Wireless transmission is inherently lossy. In the case of the MITes, two factors lead to data loss: Receiver Channel Multiplexing and Environmental Conditions.

 

The first factor is due to the nature of the RF receiver and how it listens to multiple channels via multiplexing. Intuitively, time spent listening to one channel means time is not spent listening to all other channels transmitting data. The receiver must switch between channels stopping to listen to each individual channel for a short period of time while ignoring all other channels for this period of time. This means that in order to listen to multiple channels the receiver must ignore all but one channel per time slice, and thus risk losing data on all other channels.

 

The second factor leading to data is a result of corruption of data during transmission. This corruption is due to other WIFI signals and other environmental electromagnetic noise, signal reflections, etc. A paper is currently in progress to fully document the performance of the MITes under various conditions.

 

Obviously it is vital that a single object activation (defined as the dynamic movement of an object which causes the accelerometer of the associated MITes to surpass some threshold) is not missed due to data loss or corruption. In order to overcome this problem, each time an object activation occurs, the associated MITes broadcasts its data for that specific activation six times via six identical data packets (see figure 13). The duplicate sends ensure that an activation signal is not missed due to packet loss or corruption.

 

Figure 13: MITes Transmission Scheme Example

 

As mentioned earlier there are some artifacts associated with using wireless transmission. One of these artifacts is that a receiver may receive anywhere from 1 (84% data loss) to 6 (0% data loss) identical packets for a single object activation. Activity recognition algorithms and memory constraints make it undesirable to save more than one of these packets per activation. Thus, some data filtering is done prior to saving the activation data. The distributed architecture of the MITes data collection (see figure 11) enables this filtering to be done at two levels – both at the individual processing unit level (Filter Serial Link data on PL 16 –PL21) and at the central router level (Filter UDP Link data on PL16). The same filtering technique is used at both levels. See figure X for a high-level example of the data filtering.  

 

 The filtering method used takes advantage 1.) a resendID associated with each object activation 2.) the fact that each MITes has a unique ID and 3.) the timing of MITes transmissions. Keep in mind that the overall goal is to ensure that only one data element is recorded per object activation. Every time an object activation takes place the MITes related to that object activation broadcasts six identical data packets encapsulating the data element associated with the object activation. One of the header elements in each of these packets is the unique ID associated with the particular MITes. Another header element is the Transmission ID. The Transmission ID is the same for all six data packets associated with a singular object activation. Transmission IDs loop from 0 to 6 inclusive. These numbers increment with each successive object activation.

 

The individual processing unit level filtering (That done on the individual PCs with a receiver attached) works by storing the most recently received Transmission ID associated with a particular MITes. If a packet is received with the stored Transmission ID, that packet is considered to be a duplicate and is ignored. If a Transmission ID different from the stored Transmission ID is received by a particular MITes, then this packet is forwarded on to the central routing machine and that new Transmission ID is stored. Only one Transmission ID is stored at a time. Since we have point-to-point transmission, this scheme ensures that no duplicate packets are sent to the central routing machine. Figure 14 outlines this filtering scheme.

 

Figure 14: Filtering Performed on Each Local Processing Unit

 

One problem that still needs to be overcome is the case where a receiver receives a packet with Transmission ID = 0 and then does not receive any packets associated with Transmission IDs 1 through 6. That is all packets associated with Transmission IDs 1 through 6 are either corrupted or lost. This means that the receiver completely missed 6 object activations. Further, since for every object activation six identical packets are broadcast, 36 data consecuti