daq with wireless sensor nodes - academic and event technology
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DAQ With Wireless Sensor Nodes
Chris Ruskai, Mike Hannaford, Garrett ColasDecember 13, 2011
Florida Gulf Coast UniversityDr. Janusz Zalewski
Problem Definition
• Make a wireless motion detection system with National Instruments Wireless Sensor Network
• Write code in LabVIEW for sensors to detect motion
Devices Used (1/2)
• NI WSN 9791 Ethernet Gateway
• NI WSN 3202 Wireless Node
Devices Used (2/2)
• Parallax PING UltraSonic Sensor
• Parallax PIR Infrared Sensor
Wireless Network Interface
• IEEE 802.15.4• Low‐rate wireless personal
area network(LR‐WPAN)• Intended for very low cost
devices that communicate over a short range
• Open Systems Interconnection Model
Sensor Connectivity
• Yellow – Analog Input 0 (signal acquisition for PING))) sensor)
• White – Ground for PING))) sensor
• Orange – Analog Input 2 (signal acquisition for PIR sensor)
• Red (left) – Ground for PIR sensor
• Red (right)/Green – Power for sensors (5V)
LabVIEW Code (1/6)
LabVIEW Code (2/6)
• This is an example of the PING))) and PIR sensors detecting motion and triggering an on screen LED
• The code is encapsulated in a persistent (Must be ended by terminating the program in LabVIEW) while loop.
• The PING))) sensor is attached to the AI0 terminal on the NI WSN‐3202 node and as such, is denoted by the AI0 variable.
LabVIEW Code (3/6)
• The PIR sensor is attached to terminal AI1 and as such, is denoted as AI1.
• Each sensor is connected to its own waveform graph.
• Also, each sensor is connected to a comparator.– PING))): Less‐Than Comparator– PIR: Greater‐Than Comparator
LabVIEW Code (4/6)
• Attached to the comparator is also an integer constant that the voltage of the sensor is compared to.– PING))) is compared to 4 and returns true if the voltage drops below 4 volts.
– PIR is compared to 2 and returns true if the voltage rises above 2 volts.
LabVIEW Code (5/6)
• The comparators‘ outputs are each attached to a boolean LED. – If the comparator returns true, the LED activates.– Else, the LED remains off.
Experiments and Results
• The sensors trigger properly to show that data acquisition and control work
• The upper graph displays the voltage of the PING))) sensor. As detects motion, the voltage lowers to 0 volts.
• The lower graph displays the voltage of the PIR sensor. As it detects motion, the voltage increases to 5 volts.
Conclusion
• Biggest challenge was overcoming incorrect previous documentation
• We worked hard and figured out a way to make it work and provide a working project