This Arduino code reads the output of a pH sensor connected to analog input A0 and calculates the corresponding pH value. It then prints the pH value and classification (Acidic, Neutral, or Alkali) to the serial monitor. Additionally, it generates a simple text-based graph using ASCII characters to visualize the pH value. The code uses a calibration value to adjust the pH calculation and updates the readings every second.

To test the code, you'll need to provide a value for the calibration_value variable, which is used to adjust the pH calculation. The calibration_value should be a value that is specific to your pH sensor and setup. This value is usually provided by the manufacturer of the pH sensor or can be determined through a calibration process.