Check the TDS value of water WITHOUT any TDS meter
Circuit:
Arduino
Connect 5V of Arduino to one power rail of the breadboard Connect the ground of Arduino to the other power rail of the breadboard Connect one end of a 1k-ohm resistor to ground, and the other end to the breadboard. Connect the analog pin A0 on the Arduino to the resistor. Finally, connect a wire to the resistor and another wire to 5V. Connect the free ends of these wires to the crocodile clips.
LCD Display
Connect VSS pin to the ground rail Connect VDD pin to 5V rail Connect V0 to the center pin of the potentiometer Connect ends of the potentiometer to 5V and ground Connect RS pin to Arduino pin 7 Connect R/W pin to Arduino pin 8 Connect D4 to Arduino pin 10 Connect D5 to Arduino pin 11 Connect D6 to Arduino pin 12 Connect D7 to Arduino pin 13
HC-05 Bluetooth module
Connect VCC pin to 5V rail Connect GND pin to ground Connect TX pin to Arduino pin 3 (Serves as RX) Connect RX pin to Arduino pin 2 (Serves as TX)
RGB LED
Connect the common cathode (longest pin) to ground Connect the red pin (right of cathode pin) to PWM pin 9 on Arduino through a 330-ohm resistor Connect green pin (left of cathode pin) to PWM pin 6 on Arduino through a 330-ohm resistor Connect blue pin (extreme left) to PWM pin 5 on Arduino through a 330-ohm resistor