ESP32 Metal Detector Project

The ESP32 Metal Detector project demonstrates how to build a metal detection device using an ESP32 microcontroller. Metal detectors sense the presence of metallic objects by detecting changes in electromagnetic fields induced by these objects. This project utilizes an inductive coil as a sensor to detect metal and indicates its presence based on a predefined threshold.

Components Needed

• ESP32 Microcontroller
• Inductive Coil (search coil)
• Resistors and Capacitors
• Jumper Wires
• Breadboard
• optional: LEDs or Buzzer for indication
• optional: Display (LCD, OLED) for visualization

Circuit Setup

1.Connecting the Inductive Coil to ESP32:

Coil Connections: Connect one end of the inductive coil to the GPIO pin (e.g., GPIO 34) of the ESP32. The other end typically connects to ground through a capacitor for filtering and stability.

Signal Conditioning: Include resistors and capacitors as needed for signal conditioning and noise reduction.

Instructions

1.Setup

Initialize serial communication in the setup() function with Serial.begin(9600) for debugging purposes.

Configure the GPIO pin connected to the inductive coil as an input using pinMode(metalDetectorPin, INPUT).

2.Operation

In the loop() function:

• Read the analog value from the inductive coil using analogRead(metalDetectorPin).
• Compare the analog reading against a predefined threshold (thresholdValue) to determine if metal is detected.
• Print detection status ("Metal detected!" or "No metal detected.") to the Serial Monitor based on the threshold.

3.Considerations

Threshold Adjustment: Adjust thresholdValue based on sensor calibration to optimize detection sensitivity.

Noise Filtering: Implement signal filtering techniques to reduce false positives caused by environmental noise.

visualization: Optionally, use LEDs or a display to provide visual indication of metal detection events.

Applications

Security Screening: Detect metallic objects in security checks and restricted areas.

Treasure Hunting: Use in recreational activities to find buried metals such as coins or artifacts.

Industrial Use: Integration into machinery for detecting metal contaminants in production lines.

Notes

Inductive Sensing: Metal detection relies on changes in the electromagnetic field induced by nearby metallic objects.

calibration: Calibrate the detector to distinguish between different types of metals and optimize detection accuracy.

enhancements: Consider adding features like sound alarms or data logging based on project requirements.