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

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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

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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

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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

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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

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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?