tecno4

The handheld device uses a 20-60 turn coil of 26AWG enameled wire, connected across an Arduino Uno or Nano’s pins 8 and 10. A series of pulses is continuously sent out by pin 10, which are delayed in reaching pin 8 according to the inductance across the coil. As this coil approaches other metallic objects, the effective inductance changes, thus varying the delay in the signal reaching pin 10.
This effect is sensed by the Arduino, outputting chirps on a buzzer as audio feedback when metal is nearby. To convert it into a practical device, the Nano configuration is stuffed into a Tic Tac container, with the coil held at a distance with two skewer sticks.

While looking for further ideas for a simple Ardino Pulse Induction metal detector with only one supply voltage I came across the homepage of Teemo:
http://www.digiwood.ee/8-electronic-projects/2-metal-detector-circuit

He created a simple Pulse Induction detector using the LC-Trap principle. Similar circuits were posted here on Instructable by TechKiwiGadgets. Exept that the Teemo circuit uses the internal comparators of the a PIC microcontroller, thus needing less external components
So I was challenged to use the Arduino instead of a PIC-Controller for this schematic and look how far I can get.

En este video veremos como hacer un sensor inductivo para arduino. Comenzaremos viendo los componentes electrónicos que vamos a utilizar, después armaremos paso a paso el circuito, también explicaré en detalle el código fuente y por último probaremos como funciona todo el sistema.

Un sensor inductivo es un sensor de proximidad diseñado para detectar objetos metálicos. Podemos emplear conectar fácilmente este tipo de sensores a un autómata o procesador como Arduino.
Internamente estos sensores disponen de un generador de campo magnético y en una bobina inductora que detecta el campo generado por el propio sensor.
La presencia de un objeto metálico modifica el campo inducido. Al tener una menor resistencia magnética (reluctancia) el campo magnético se “alarga”, incrementando la corriente inducida en la bobina sensora.