Pulse Metal Detector Metal Sensor Metal Search Clone PI-W DIY Kit Module M158.1

Description

Specifications
● Coin detection depth, to 25 – 28 cm
● Depth of detection of large objects 150 cm
● Minimum supply voltage, 6,5 V
● Supply voltage, 9 – 14 V
● Current consumption, 40-150 mA
● Impulse current consumption, 1 – 2 A
● Display Type, LED / Audible
● Board dimensions, 75 X 35 x 36 mm

*The current consumption depends on the volume setting of the
speaker. At maximum volume, it can reach up to 240mA.

Device description

The principle of operation of the metal detector is based on the excitation
of pulsed eddy currents in a metal object and the measurement of the
secondary electromagnetic field induced by these currents. In the OU U1
and U5 circuit, a differential and non-invertingamplifier, as well as a
measuring integrator, are implemented. Chip U2 is an analog key. The
U3 chip is a microcontroller that performs analog-to-digital conversion.
On the field-effect transistor T1 assembled a powerful key.
LEDs D3 – D12 are designed to indicate the detectedt arget and indicate the
device settings, which is carried out using the buttons SW2 — SW6.

Assembling and setting up a metal detector

Settings are carried out away from industrial interference and large metal
objects. If at this moment any metal object is near the sensor coil, the device, it
is wrong. The power voltage is supplied to the contacts +VCC, 12V from the
battery (in cases with the power supply, there may be interference that will lead
to difficulty setting up the device). The search coil is connected to the contact
L1, and the SP1 contact is 8 Ohms/0.5 watts. When feeding, the device is
initiated by the device accompanied by blinking and characteristic sound. The
SW3 SW6 buttons set the minimum barrier value. The tuning resistor R3 is
rotated until the device begins to make sounds on its own, and then we turn the
R3 a little so that the device is silent. At each position of the tuning resistor, we
press the SW4 reset button and check the sensitivity. A good result by air can
be considered 22-25 cm for five cents. The setting of the metal detector can be
considered finished. To look for a metal, we install a barrier in which the
“instinct” of the device will be maximum with satisfactory stability. A well-tuned
device does not give false works at 3-4 barrier LEDs.

Making a search coil

For the manufacture of the search coil will need a rigid non-metallic mandrel
Ø from 20 cm or more. The larger the diameter of the coil – the higher the
“intuition” of the metal detector to large objects (for small and medium-sized
objects the diameter of the coil is about 25 cm) 25-27 turns of enamelled
copper winding enamelled wire (Ø0.5 – 0.8 mm ). The ends of the wire to fix
and solder on the board to the contacts L1. In order to give a rigid form to
the sensor, you can use impregnations that do not conduct current and do
not dissolve the enamel insulation of the wire. For example, “TSAPON
varnish”, “Epoxy resin” or “polyurethane foam”

Quick User Guide