The Baby Protector: Baby Monitor to protect against dogs Ermin E. Arias Advisors: Professor Hassib Professor Hedrick March 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 percent 1 of the households own a dog. ml

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

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

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.

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. t w = 1.10R A C (Where t w is the resulting time)

“Stretching” the Signal… Figure 3: Signal as received from the comparator into the 555 timer. Each pulse has an ON time of 15 microseconds 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 Inverter 555 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 Figure 5a: Signal from the receiver before going through the comparator. Figure 5b: Signal from the receiver after going through the comparator.

Basic Stamp Transmitter and Receiver Single-board computer that runs the Parallax PBASIC language interpreter in its microcontroller. Parallax MHz RF transmitter Parallax 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 reviews/index.html?referrer=yahoo_ssp reviews/index.html?referrer=yahoo_ssp Monitor/dp/B000CDNECQ - radio info receiver

Questions?