Circuit diagrams and schematics - Electronic projects

This is a simple alarm circuit.This work, when the switch S1 (sensor) tilted away from vertical.The alarm stops when the sensor back to the old form. S1 sensor is a mercury switch.Contact is a normal closed.When the switch is placed in a vertical.Transistor Q1 acts as a switch off, buzzer immediately.When the sensor back to [...]

This circuit uses a thin piezoelectric sensor to sense the vibrations generated by knocking on a surface; eg, a door or table. Basically, it amplifies and processes the signal from the sensor and sounds an alarm for a preset period. In operation, the piezoelectric sensor converts mechanical vibration into an electrical signal. This sensor can [...]

So the sump pump quits and because you dont live in your basement youre never the wiser. The result? A flooded basement! Now build a cute little water sensor alarm to let you know! Simply mount the alarm in the area you want to sense water and the moment it touches the contacts the included [...]