1. AMBIENT SENSOR RESEARCH FOR
SLEEP QUALITY ENVIRONMENTAL ASSESSMENT
Martin Ortega1, Steve Warren2, Charles Carlson3
1Kansas State University, Department of Electrical & Computer Engineering, Manhattan, KS USA; 2Heartspring, Wichita, KS USA
We thank all the staff, development team, and everyone associated with this research project. We extend our thanks to the RiPS Program for all the support, guidance, and encouragement throughout
the summer. This work was supported by National Science Foundation grant No. 1305059 (KS-LSAMP), and is also based upon work supported by the National Science Foundation (NSF) General &
Age-Related Disabilities Engineering (GARDE) Program under grants CBET–1067740 and UNS–1512564.
Children with an autism spectrum disorder (ASD)
experience sleep-related problems more often than
neurotypical children, and these issues directly affect
their daytime behavior and their cognitive development.
Current technology is not suited for use with autistic
children, there then exists a need for an improved
nighttime monitoring instrument for severely disabled
children. Kansas State University researchers are
working with students in Heartspring School in Wichita,
KS, to develop an unobtrusive bed-based suite that will
be able to monitor ambient conditions in the room,
check physiological signs, and other events.
Relative Humidity Detection
Figure 2 is the humidity sensors VI – which is
created through LabVIEW.
Importance
This research focuses on the bed-suites ambient sensors
which measure relative humidity, and sound power level
in the environment. Ambient sensors are connected via
NI 9205 module (16 16-bit differential channels, fs = 250
Hz) instrument. These modules are connected to an
Ethernet network - using a National Instrument 9184
cDAQ chassis. The signals are then managed with a
LabVIEW virtual instrument. This VI allows us to create a
graphical representation of the signal, and is where the
sensors measurements are portrayed. This also allows us
the option to store data to perform analysis later.
Methods
Sound Power Level Detection
To detect sound power level (SWL), the “SparkFun Sound
Detector” is used – which uses sound conditioning to
detect when sound is present. This works similar to the
humidity sensor by giving an analog representation of the
signal - which is amplified by a LMV324 - with increasing
amplitudes as sound intensity increases. The envelope
signals are recorded and processed, then converted into
a SWL in decibels (dB). The voltage is also then
converted to SWL by using a known relationship.
Data analysis from these sensors will be used to
determine the effect of ambient conditions on sleep
wellness.
Future work includes transitioning into a wireless network
to allow data to be saved via a cloud-network, and to
make the bed far more unobtrusive.
Conclusions | Future Research
The AM2001 humidity sensor (fig. 1, 1a) is used to
determine the relative humidity (RH) in the room. This
works by utilizing thermoplastic polymers which detect
moisture levels in the air, which is then written as a
voltage (fig. 2). Using the sensors data sheet we’re able
to calculate the relative humidity from the voltage with
the formula ‘y = 36(x) – 10’. When certain conditions
are met, the VI is programmed to alert the user.
Figure 1 shows the two sensors used to measure
relative humidity, and sound power level
Figure 3 shows the envelope and audio signal from the
Sound Detector. The envelope signal is used to detect
sound intensity