You've got mail

摘要

Many e-mail programs provide a "beep" or a pop-up message box signaling the user that a new e-mail message has arrived. If the you are too far from the computer to hear the audible signal or if the monitor is turned off, then you miss the new-mail audible and visual signals. The simple circuit in Figure 1 (see pg 136) latches on an LED and an audio sounder when an appropriate new audible e-mail signal occurs. The method replaces the normal e-mail sound.wav file with a .wav file of any valid recorded dual-tone multifrequency (DTMF) sound. The circuit listens for the DTMF tone and latches on LED D_1 and the piezoelectric buzzer, P_1. R_1 biases the microphone's FET, and C_1 couples the audio to the M-8870 DTMF-receiver, IC_1 (Tel-tone Corp, www.teltone.com). IC_1 integrates both bandsplit-filter and decoder functions into an 18-pin DIP.