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The Baby Protector: Baby Monitor to protect against dogs. Ermin E. Arias Advisors: Professor Hassib Professor Hedrick March 1, 2008. In this project I modified a baby monitor to: A) Prevent a dog from getting into the infants crib. - PowerPoint PPT Presentation
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The Baby Protector: Baby Monitor to protect against dogs
Ermin E. AriasAdvisors: Professor Hassib
Professor HedrickMarch 1, 2008.
What is this project about?
•In this project I modified a baby monitor to:
A) Prevent a dog from getting into the infants crib.
B) Notify the parent that their pet is in the child’s room.
Motivation
My sister recently had a baby In the United States thirty-nine percent1 of the
households own a dog.
http://www.hsus.org/pets/issues_affecting_our_pets/pet_overpopulation_and_ownership_statistics/us_pet_ownership_statistics.html
My Idea
To modify a commercially available baby monitor by combining it with an invisible dog fence. This will train the pets to remain within a specified distance from the infant’s crib.
+
Performance Criteria
The dog collar will produce a shock if the dog is within 12 ft.
Wirelessly notify parent’s unit up to 600 ft away when shock is triggered.
Cons of today’s monitors
Interference Static Battery power
It can only MONITOR, it does not provide any immediate assistance.
Disclaimer
The safety and effectiveness of modern electronic training devices are supported by The Humane Society of the United States, The American Society for the Prevention of Cruelty to Animals (ASPCA) and the International Association of Canine Professionals, among others.1
1 The Facts About Modern Electronic Training devices
http://www.discount-pet-superstore.com/repeated_images/Truth%20about%20static%20shock.pdf
Invisible Dog Fences
Protects pets Protects owner’s furniture and space How does it work?
A transmitter A lightweight receiver worn on your pet's collar
Fence used:Indoor Innotek Zones Instant Pet Barrier
Features:
The transmitter runs on batteries
It works for cats and dogs
Adjustable Correction Zone - Adjustable boundary, set the correction field from a few feet all the way up to 12 feet.
Monitor used Evenflo Whisper Connect 900-Mhz Tria 3-Way Monitor
Product Description
3-way communication has a walkie talkie feature
Range of up to 650ft
Out-of-range indicator and alarm
7 levels of sound lights
Low battery indicator
Rechargeable batteries included Parent unit finder
How my idea works
Transmitter placed near baby’s crib sends RF signal.
Receiver in collar picks up the signal that the transmitter is sending if pet is too close.
Collar emits a shock. Shock signal causes second transmitter to notify parent.
If pet doesn’t leave area
If pet leaves
End
Shocks and parents notifications continue.
Transmitter-Receiver Frequency
Figure 2: Frequency graph of the transmitter, it shows that the transmitter is transmitting at 6.25 kHz frequency. Note: Peaks are ‘ringing’ caused by the inductance on the antenna
-1 -0.5 0 0.5 1 1.5
x 10-3
-0.25
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2Oscilloscope Channel 1
Time (s)
Voltage (
V)
Testing the collar results
Figure 1: As we can see by the figure above, the shock is emitted in fast pulses. Each pulse consist of an ON time of 15 microseconds, this continues for 6 seconds.
-0.025 -0.02 -0.015 -0.01 -0.005 0 0.005 0.01 0.015 0.02 0.025-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6Oscilloscope Channel 1
Time (s)
Vol
tage
(V)
The 555 Timer Trigger pulse at pin 2 initially sets
the 555 internal flip flop ‘on’ by comparing the input pulse to 1/3 of the supply power to a second comparator.
555 stays ‘on’ until this timing cycle turns it ‘off’ by resetting the control flip flop.
tw = 1.10RAC (Where tw is the resulting time)
http://www.williamson-labs.com/pu-aa-555-timer_fast.htm
“Stretching” the Signal…
-0.025 -0.02 -0.015 -0.01 -0.005 0 0.005 0.01 0.015 0.02 0.025-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6Oscilloscope Channel 1
Time (s)
Vol
tage
(V)
Figure 3: Signal as received from the comparator into the 555 timer. Each pulse has an ON time of 15 microseconds
-0.025 -0.02 -0.015 -0.01 -0.005 0 0.005 0.01 0.015 0.02 0.025-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6Oscilloscope Channel 2
Time (s)
Vol
tage
(V)
Figure 4: Signal after going thru timer.
Note: Signal has expanded to last 8 milliseconds
Detailed Block Diagram
Shock triggers the comparator
Receiver in dog collar receives signal and generates shock IF necessary
Transistor Inverter555 Timer
Transmitter next to monitor continuously sends RF signal
Detailed Block Diagram Cont’
Transmitter sends a signal to the receiver in the parents unit
Signal received by receiver, goes thru third comparator = add hysterisis to get rid of instability
Signal goes into microprocessor
Voice signal produced and injected into monitor’s microphone
Getting rid of instability
-0.01 -0.008 -0.006 -0.004 -0.002 0 0.002 0.004 0.006 0.008 0.011.4
1.5
1.6
1.7
1.8
1.9
2
2.1
2.2Oscilloscope Channel 1
Time (s)
Vol
tage
(V
)
-0.01 -0.008 -0.006 -0.004 -0.002 0 0.002 0.004 0.006 0.008 0.01-1
0
1
2
3
4
5
6Oscilloscope Channel 2
Time (s)
Vol
tage
(V
)
Figure 5a:
Signal from the receiver before going through the comparator.
Figure 5b:
Signal from the receiver after going through the comparator.
Basic StampTransmitter and Receiver
Single-board computer that runs the Parallax PBASIC language interpreter in its microcontroller.
Parallax 433.92 MHz RF transmitter Parallax 433.92 MHz RF receiver
Fast data transfers
Conclusion
The device prototype has been tested and it meets the performance criteria. Sends a wireless notification to the parent unit up to 650ft away if dog collar
triggers shock.
Future Work
Make it more “user friendly” Design and manufacture a printed circuit board.
Acknowledgement
Gene Davidson
References
http://www.consumersearch.com/www/family/baby-monitor-reviews/index.html?referrer=yahoo_ssp
http://www.howstuffworks.com/question333.htm http://home.howstuffworks.com/pet-fence6.htm http://www.amazon.com/Evenflo-Whisper-Connect-Nursery- Monitor/dp/B000CDNECQ http://www.rfdigital.com/index.htm - radio info http://www.howstuffworks.com/radio-spectrum.htm - receiver http://www.acornpetco.com/index.php?crn=213&rn=460&action=show_detail http://www.semiconductorstore.com/Pages/asp/search.asp http://www.wireless-dog-cat-fence.com/Indoorwirelessdetails.html• http://www.williamson-labs.com/pu-aa-555-timer_fast.htm
Questions?
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