Design and construction of sound detector with alarm

Thesis Abstract

This project is design and construction of a sound detector with alarm system was done primarily to detector sound. It can be use in industrial and domestics. It employ four discreet stages with power supply which power the system.

The 1st block is pick up amplifier containing the microphone and the input which serve as a transformer which the function is to pick up the smallest sound that comes close to the amplifier

The second block is comparator with hysterias. The function as analogue to digital convector and also it help to accumulate amparm sound like sound of the gun short or any other heavy sound  

Block three. This is transistor switching this stage consist three bipolar function transistor (BJI) with a decay circuit found using capacitor time constant (T – RC) with a 12v Re let, it output work function is to switch the alarm circuit.

Block four. This is the Alarm circuit, it’s function is the alarm tone. It is an stable mutivibertor that produce 1kH2 tone frequencies which sound as alarm signal with loud speaker which serves as an output transformer.