Distant Managed Corona Safety Bell

Fig. 1: Author’s prototype on a breadboard

The World Well being Group (WHO) recommends that everybody ought to rub their fingers with cleaning soap for a minimum of 20 seconds earlier than washing with water to stop transmission of the novel Corona virus, which is once more on rise, along with social distancing. The 20-second interval will be checked with wristwatches and the stopwatches on cellphones, however these will not be handy to make use of whereas washing fingers. This proposed circuit rings a buzzer for 20 seconds and switches on an LED for audio in addition to visible indication (for these with listening to points).

The writer’s prototype is proven in Fig. 1.

The circuit for this alarm, proven in Fig. 2, includes a 9V battery, 5V voltage regulator LM7805 (IC1), timer NE555 (IC2), relay driver ULN2003 (IC3), 5V SPDT relay (RL1), and some different elements. Resistor R2 and capacitor C2 determine the time of monostable, which is round 20 seconds right here. This output time interval of IC2 at its pin 3 (monostable multivibrator constructed round NE555) will be calculated utilizing following relationship

Obtain PCB and Element Format PDFs: click on right here

This venture will probably be printed in a number of weeks. If you wish to entry it now, consult with Electronics For You’s January 2023 Situation–print or ezine version.