Using RE46C190 photoelectric smoke detector circuit can be designed a very simple and low power smoke detector alarm project..
With minimal external components, this smoke detectors alarm circuit will provide all the
This ultrasonic proximity detector circuit is designed using few external electronic components .
If an solid object is moved in close proximity to the front of the buzzer , the relays drops out .
The R4 ( 100k ohms potentiometer ) sets the current fed to the buzzer ( sounder) . The potentiometer must be adjusted to a sounder point where the buzzer begins to sound .