energy-efficient operation of gsm-connected infrared rodent sensors
TRANSCRIPT
Energy-efficient operation of GSM-connected infrared rodent sensor
Gábor Paller, [email protected] Gábor Élő, [email protected]échenyi University, Győr
2016 February 19
Precision agriculture and the agrodat.hu project
• Precision agricultural management
• Better control of production risks and costs
• Information systems supporting decisions
3
Crop production
AgroDat.hu project
Main objective: Establish an agricultural knowledge centre and decision support system• based on data gathered by an
innovative, complex sensor system and from international open repositories
• relying on big data, cloud, and HPC technologies
to support precision agriculture.
Duration: 2014-2017Budget: 2.4 Mrd HUF (appr. 8 MEUR)URL: www.agrodat.huConsortium:
Local
Sensor
Global
• Information about environmental and vegetation processes (supplied off-line)
• Sensors and data capture tools• Data processing system• Visualization• Decision support
5
Elements of the agricultural decision support system
Sensor lineup
l 2014 – soil and environmental sensors with simple scalar output – done
l 2015 – camera sensors in multiple wavelengths with simple and intelligent triggers – research phase completed, field-ready implementation in progress
l 2016 – making the camera sensor mobile
Soil sensor
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Proposed system architecture
Sensor unit
Sensorcontrol
NetworkCommunication
+App. logic
(Telit GL865)
Data server
GPRS/HTTP POST requests
WSGI HTTP server
Database adapter
Data visualization
SMSC
End user
Mobile network
SMS
HP DSM (Dynamic SIM Management)
SMPP 4.3+
Sensor management server
Management user
Server farm
Camera sensor development
Camera sensors
l Mission: observe plants and pests in wide frequency spectrum (visible and invisible)
l Simple case: take a series of pictures and videos at given time spots and upload them to the server
l More complicated: detect an event of interest and upload only if something interesting is happening
Camera sensor development
l Use case: common vole detection
l Overpopulation due to mild winters
l 2014 damage estimation: 500000 tons only in winter wheat
l Night animal: cameras in different wavelength are needed (short-wavelength infrared and long-wavelength infrared are being tried)
l Energy consumption: send images only if there's high chance of having animals in the picture → image processing on the sensor
Advantages of the use case
Common vole in short-wavelenght infrared
Animal
Common vole in long-wavelenght infrared
Dynamic mapping to 256-levelgreyscale image
Image processing in the sensor
l Image thresholding – 80% static thresholdl Get rid of spurious patches – contour tracing+convex hull filling
l Close gaps - dilating by a kernel of 6x6l Calculate circles of interesting objects – contour tracing+enclosing circles
l Find out if the circles move – match the circles with the circles on the previous image and flag the circles that don't match
Image processing in the sensor
Eq – input image after greyscalingTh – after thresholdingC1 – after contour tracing + filling convex hull C2 – after dilatingCircle – enclosing circle
Cost of sending an image
BeagleBone Black (TI Sitara AM335x)+Telit GL865 modem, image size: 4KbytesArchitectures:- GL865 as a modem, all the logic (image processing+communication) is on the Sitara CPU – 10.755 mAh- Image processing on the Sitara CPU, communication logic on the GL865 – 3 mAh
Power consumption of communication state machines
l Idle consumption of the Sitara CPU is a problem in case of action-and-wait type algorithms (typically communication state machines)
l If the “wait” phase is long then the processor could be put into a low-power mode.
l A separate low-power CPU is justified just for communication tasks.
Sensorcontrol
NetworkCommunication
+App. logic
(Telit GL865)
Generic model
Same architecture for scalar and image sensors
Soil sensor
Data acquisition: ATxmega128u4
NetworkCommunication
+App. logic
(Telit GL865)
App. Protocol #1
Camera sensor
Acquisition and processing: TI Sitara AM335x
NetworkCommunication
+App. logic
(Telit GL865)
App. Protocol #2
Use case categorization
Use case Power consumption balance between the processing and the
communication activities
Images taken at predetermined moments of time and sent
No image processing, no balance
Images are taken continuously, sent if relevant feature is found
Continuous image processing, no balance*
Images taken at predetermined moments and sent only if relevant feature is found
Justified if the image processing cycle consumes less than sending the image
* Balance would mean that we compare with continuous image streaming whichis not possible over GPRS due to its low bandwidth.
Cost of image processing vs. sending
Image processing(acquiring and processing 5
images)
Sending the image
0.62 mAh 3 mAh
However:l Sitara consumes 156 mA in S3 state (69 secs to reach 3 mAh)l It takes 4.78 mAh to perform a shutdown-reboot cycle
l No power saving possible in use case #3 due to high idle consumption!
Takeaways
l Low-power, low-consumption devices (e.g. microcontrollers) are justified even if there's a full-featured CPU in the system. Typical use cases: sensor control, communication.
l No magic bullet: high software engineering productivity on embedded Linux but high power consumption too.
l Look for idle consumption!l Linux system optimized for extra-fast shutdown-bootup cycle may work (but you need a low-power sensor controller)
