This simple project will add sound activated control to any digital camera by ending a time controlled pulse into a relay board that is connected to the dual stage camera shutter switch. The sound is picked up by a sensitive microphone and then fed into an operational amplifier set up as an adjustable comparator so that the sensitivity can be controlled. The level of sound activation can be adjusted to respond to very faint sounds such as voices or footsteps and also adjusted to only respond to loud sounds such as music or hand claps. As a security device, this project will allow a high resolution image to be captured in response to some type of nearby sound.
Read more about this and other DIY electronics projects: Lucid Science Electronics from the Fringe: Sound Activated Camera – DIY electronics project