Timer with limited lifespan is provided with light-emitting diode and audible signal and uses microchip without crystal for fixed time periods between 1 week and 1 year

摘要

The timer with a limited lifespan is provided with a light-emitting diode and an audible signal. It uses a microchip without a crystal for fixed time periods between 1 week and 1 year. After starting the timer, the microchip controls the light-emitting diode to provide a regular light signal, indicating that the timer is active. After the elapse of a specifically set time, the microchip (Ch) controls the loudspeaker (S) to emit short sound signals at regular intervals. Also after the elapse of the specifically set time, the microchip controls the light-emitting diode (L) to flash at a clearly higher frequency. The components used are a chip (preferably PIC12C508AOSN or similar), a piezo transducer without is own oscillator, a light-emitting diode with a resistance of 180 ohm and a tolerance of 5% and a battery with a capacity between 80 and 210 mAh.