The Door Guard Knob Alarm circuit with touch system. When thief caught on door handle, makes alarm once. Use the the detector capacitance within the body.
This is the cheap fire alarm circuit that Use principle of infrared sensor smoke. When cause events fire. The principle is simple and affordable.
This is an Simple blown fuse alarm circuit for AC line, cause we know immediately when broken fuse circuit and it has a few components so easy build cheap.
Use high frequency out of the piezo speaker and IC-556 is base as oscillator between 22kHz and 56kHz
This projects is safer and more convenient.
Why withered trees. It is dying. Oh, the soil is too dry. How can we use electronics to help trees? Build Simple soil moisture alarm circuit. The tree is very…
Suitable for beginners. Build a simple, but widely applied.
This is two tone alarm use op-amp IC, LM3900 (Quad Amplifiers). It produces the frequency of square wave in 2 level. It is high frequency and low then mix the…