Electronic Projects & Many More

We recently build the answering machine based on 89c51 microcontroller.It uses 63kb eeprom to store the sound and uses adc0804, dac 0808, two ram 62256, 74hc373 and operational amplifier. This answering machine is capable recording 14 sec of audio sample. Its working is simple. it detects ring from ring detector and hangs on the phone after 10 sec of continues ring, then the voice starts recording in RAM. A playback button makes replay the recorded sound.The backup battery of 1.2v makes it significant even if the power cuts. This project was shown for the enginnerings final year project ( i'm not the final year student- now i'm just studying enginnering may be i'll do more than these in my life). If anyone is interested on doing their projects like answering machine like mine then feel free to mail me at ujwal2@gmail.com.

I'm even thankful for the help of Rajkumar Silwal, Saroj Shrestha, Roshan Karki and one i forget.