Project Description
This project combines some simple modules together, one to detect telephone rings, and one to pass or mute sound. Hooked together, they’re a complete device and one you can use anywhere. Figure 1 shows the system concept — the ring detector monitors the telephone line and, when a ring signal is sensed, outputs a control signal to the actuator. The actuator determines how long to keep the sound muted, and connects to the audio subsystem of the television to accomplish the muting operation.
There are many ways to implement the system, such as the following:
Ring Detector — The detector can sense the ring signal on the telephone line, or could sense the ring sound from telephones connected to the line. A more extreme approach would be to sense the ring waveform sent to wireless telephones.
Actuator — The actuator can mute the amplifier itself, change the volume of the signal input to the amplifier, or interrupt the signal before it gets to the speakers. It can use several different control paths to accomplish its task, including wireless, direct wiring, or power line control wiring.
You can do more than connect the project to your television — it connects equally well to your home theater or stereo, and is useful for muting games as well as video and audio.
FIGURE 1: TV mute block diagram