Now it is very easy to build your own siren sound alarm, small enough to be carried in a garment pocket. This powerful audio-visual alert device is realized using the renowned Arduino platform. The 9V ...
// Pin A4 (Pin 18) monitoring: LOW = SIREN_ON (repeat every 0.5s), HIGH = SIREN_OFF // Connect a pull-up resistor between A4 (Pin 18) and +5V. // Connect momentary Normally Open (NO) switch between ...