Humidity SensorWhat I present on this occasion is an indicator of moisture, as you can see in the diagram, this is a very few circuits with components on the same assembly is not complex.
The heart of the circuit is the popular operational amplifier 741. When a high resistance is presented in the electrodes, the LED1 remains on, If we put in a container with water, for example, water completed the circuit and the LED2 will turn on and turn off the LED1, as simple as that. As electrodes can use copper wire rigid number 10 or 12. Pue4des extend about 5 meters from the sensor circuit. To adjust the point of transisción makes use of R3 (potentiometer).
integrated circuits :
IC1: operational amplifier 741
LEDs : green and red
All of a 1 / 4 watt
About 2 pieces of copper wire number 10 or 12 or rigid sheets of copper to be used as electrodes.
pcb expensive components
pcb expensive tracks print