In this tutorial, we will learn how to make a simple metal detector circuit. These metal detector circuits are being used in plenty of places. Most security officers use it to detect metal devices like guns, knives, etc.
A metal detector is a circuit that senses any metallic object close by. These metal objects are very useful to detect the presence of any hidden object. A simple metal detector uses a 555 Timer IC. The Metal detector circuit is a mandatory part of security. They use it to prevent any unlawful entrance of guns and bombs into public places. This is specially designed for the security system using a proximity sensor.
Hardware Components
The following components are required to make Metal Detector Circuit
| S.No | Component | Value | Qty |
|---|---|---|---|
| 1. | Breadboard | – | 1 |
| 2. | Battery | 9v | 1 |
| 3. | IC | NE555 Timer | 1 |
| 4. | Resistor | 47k | 1 |
| 5. | Electrolytic Capacitor | 10uF, 2.2uF | 1, 2 |
| 6. | Speaker | 8 ohm | 1 |
| 7. | 150 Turns of 10cm diameter coil (of any gauge) | – | 1 |
555 IC Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of 555 Timer
Metal Detector Circuit
Working Explanation
Basically, a metal detector is an electronic device that includes an oscillator. This oscillator generates an AC current. The alternative current then passes through the coil. It produces an alternating magnetic field. In case any of the parts of the metal are close to the coil. This will produce an eddy current in the metal. This will result in producing a magnetic field of its own in the metal. Now then If another coil is used to determine the magnetic field.
The coil observes the change in the magnetic field. The main components of a simple metal detector are an LC oscillator, a proximity sensor, and an LED or a buzzer. The LC circuit is the combination of an inductor and a capacitor in parallel. Whenever it senses any metal object near it activates the proximity sensor. The proximity sensor brights an LED or makes a buzzer sound.
Application
- Metal Detector Robotic Vehicle using RF Technology
- For security purposes in banks, shopping malls, etc security officers use this circuit
- Metal Detector Robotic Vehicle Operated by Android Application
