Flood Sensor with 12F683

The water detection time is less than 10 seconds. Since the microcontroller enters a low consumption state between readings to preserve battery life, this state is always 10 seconds long. If water reaches the probes while being in the low power state it will have to wait until it finishes the sleep state before it can trigger the alarm. Also, the probes should be placed not to far apart from each other and they never should touch each other. The more probe area available for water sensing the better. After everything is checked ok the detector will enter it's normal state. Every 10 seconds it will check the probes and the battery's voltage.
Flood Sensor with 12F683 - schematic

The box that I used did not had enough room for all components, so I had to place both leds and piezo on the exterior of the box. That detail didn't make any difference since the leds should stay visible and the piezo free to make the loudest sound possible. The probes can be made from any conductive material, but I preferred not to use copper because it deteriorates with time. In my opinion a good material to be used is stainless steel or aluminium. However, maintenance should be done from time to time checking the probes and testing them with water. Turning on the circuit, both leds and piezo are tested. Also the probes are checked. If the probes are sensing water or any kind of leakage it will turn on the red led and it will trigger the piezo. If water gets between the probes the detector will enter the alarm mode where the red led will turn on and the piezo will start making a loud sound. The detector will keep itself in alarm mode until S1 is pressed. If the battery's voltage is good, the green led will flash every 10 seconds but if the voltage reaches 7V the red led will flash every 10 seconds and the piezo will make a short sound to indicate it's time to change the battery. The probes I used in my project are made from aluminium.

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