Senior Project – Electrical Engineering – 2005 Wireless Baby Monitor Nelson Rosario, Farida Siddiqi Advisors: Professor Ekram Hassib Professor Emad A. Andarawis  Abstract: The principle behind our wireless infant monitoring system involves the activation of a video camera by the detection of a child’s cry in the environment. Once the video camera has been activated, video and sound are transmitted to the parent, through wireless communications, in which the parent will receive this data on a handheld device. In this project the theory behind infant cries is researched and implemented in the design of a triggering methodology for activating the monitoring system and alerting the parents. Why design a new wireless baby monitor? - A design which will combine the features offered by individual wireless baby monitors into one system and incorporates video and audio transmission with the detection of sound. Design of FAN05 Microphone/Camera- captures analog audio/video signal and sends to transmitter Transmitter- receives audio/video signal converts to modulated radio frequency signal and transmits to receiver Receiver- picks up modulated radio frequency, converts it to original audio/video signal Trigger Circuit – Triggers the monitor to turn on and emits an audio signal to get the response of the parent. Monitor- device which allows parent to see child Video Results for FAN05: video signal when a hand is approximately 7.5 inches from the lens video signal when a hand is standing approximately 21 inches from the camera lens Analog Audio Signal Results: Microphone signal : music is playing on the computer volume 61, approximately 15 inches from computer speaker Microphone signal: music is playing on the computer volume 100,15 inches from computer speaker Infant Cry Modes: Infants have three modes of vocal mechanisms: -Phonation: the vocal cords are fully vibrating periodically at a frequency between 250 Hz and 650 Hz. -Dysphonation: turbulence noise is generated at the vocal cords and is modulated by vocal fold vibrations. Frequency between 650 Hz- 850 Hz -Hyperphonation: when the frequency of the vocal cords shifts to 900 Hz Hz. For our purposes we are interested in this frequency range. The Trigger Circuit: The trigger circuit is the portion of the apparatus that consists of the microphone, amplifier, bandpass filter, diode rectifier, low pass filter, comparator, and timing circuit. The trigger circuit starts with a child's cry that will be picked up by the microphone. Then the signal will be amplified and sent through a band pass filter. If the frequency of the voice is between 900 Hz and 1200 Hz then the signal will be rectified by the diode then the signal will pass through a low pass filter to eliminate the high frequency components. The resulting DC signal will trigger one of the comparator inputs. Then a reference voltage of 0.5V will be connected to the second input of the comparator. When the rectified signal is lower than 0.5V then we have a low output. When the rectified signal is higher than 0.5V then we have a high output. When the output of the comparator is high this will trigger the reset pin at the TLC555 timing circuit generating a square wave output. The square wave is added to the video and audio signals to be transmitted. This square wave is used to generate an alarm signal at the receiver. Pspice-Filter Circuit Design Results of Constructed Circuit Not triggering at 800HzTriggering at 1100Hz Triggering at 1200Hz Results of Pspice for filter design Output of TLC555 Timing Circuit