Transistor is not switching-Raindrop sensor with LED (Later Buzzer will be used)

Question

I am creating a small application in which on detecting the water the Buzzer will ring. But right now I am testing with LED instead of Buzzer.

Raindrop Sensor datasheet link: https://components101.com/sensors/rain-drop-sensor-module

I am using a Raindrop sensor:

And RGB LED:

I don't need any MCU in this project. I connected the sensor to the 5V and GND and connected the A0 (Analog Pin) to the Positive of LED.

Note: 5V and GND were supplied from Arduino UNO

Like this:

^{simulate this circuit – Schematic created using CircuitLab}

But LED turns on as soon as I connect power to the circuit. And when I drop water on the sensor LED turns OFF. Opposite of what I want. So I thought of using a transistor as a switch to turn LED ON on detecting water.

Below is my circuit:

^{simulate this circuit}

But this isn't working at all. Any guide on how can I get it to work with or without transistor.

New Try

^{simulate this circuit}

Answer 1

I would like to help you with your problem. Please consider that we all do it for mutual learning and helping each other for free. Learning by doing is the best way to learn. Consider the comments and questions as a good wayguide to address the problem and learn.

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Please use the digital output pin for the module.

As per the schematics, it is the output of the comparator. You don't need a microcontroller to use the digital output pin.

Below is an example circuit I recommend.

1. The digital output of the module can be connected to the base of the Q1.
2. The three LEDs can be replaced by your single LED. Forget the tricolor LED. Please use a simple one for now.
3. When there is no water (rain), the digital output of the comparator will be high. This will turn on the Q1. This will turn off the MOSFET M1. Hence the buzzer (LED) will be off.
4. When there is rain, the Digital output will go low. This will turn off the BJT Q1. MOSFET gate source vorlage is high enough to turn it on. Bizzer (LED) should be on now.
5. With a multimeter please check the behaviour of Digital Output pin D0 to make sure it is toggling. Use the available options to tune your circuit.