Connecting the electric circuit to the lighting installation can be on or off the light by whistle. The circuit is built using the UM3763 chip, a switch controlled by sound. Buzzer piezo-ceramic is used in circuit as a microphone. When it captures a tone frequency between 1.2 kHz and 1.8 kHz, output pin 8, will flip (bulb goes off to on, or turn to off).
Using this electronic scheme can be built an electronic timer which can be set to measure a maximum of 60 hours. The electronic timer allows the fixation of some intermediate time. On reaching this point, a buzzer will sound. The circuit is built using ICM7217 integrated circuit, manufactured by Intersil, which contains a CMOS counter up / down, with 4 digits and display properly.