تويت
[
- LEFT] We managed to develop an original metal detector, principle of action which differs from the classical schemes of metal (in beats, induction, pulsed). The result was a simple device which, nevertheless, has some good characteristics. This metal detector can be recommended as entry-level device. It can be used for beach searching, learning metallodetektsii, as toys, etc.
- Our article on this project were published in the 130-m issue (May 2001). American Journal Circuit Cellar and journal RADIOHOBBY(February 2002).. Also, this device is devoted to the corresponding chapter in the book of Andrei Shchedrin's "New metal detectors to search for treasures and reklikvy.
- Main technical characteristics of the device
- * Supply vol***e 7-15V;
- * Supply current, no more than 20mA;
- * Static and dynamic modes of search;
- * Discrimination - ferromagnet / neferromagnetiki;
- * Cvetovaya and sound indication;
- * Smooth adjustment of sensitivity;
- * The regime ignored the iron ******s ( "Iron Mask").
- * Depth of detection with the probe diameter of 190mm (in air):
- o Coin diameter 25mm ...... 11cm;
- o Pistol ...... 17cm;
- o Helmet ...... 37cm.
- Currently, this metal detector manufactured by Master Keith as a set of self-assembly NM8041 [/LEFT]
- Schematic diagram
- Appointment of government (for version 5.1)
- S0: reset the device;
- S1: Mode On - Static, Off - Dynamic.
- S2: the power switch.
- R6: Adjusts the sensitivity.
- J0: off - Filter N1 in the dynamic mode, on - Filter N2.
- J1: off - Sound for iron ******s included, on - The sound is turned off for iron ******s.
- Operation is
- If the switch S1 is closed, then the device switches to static mode. This mode when approaching the coil to the ferromagnetic target sequence beginning LEDs light up VD3, VD2, VD1. If the coil closer to nonferromagnetic metal ******, it will be consistently illuminated LEDs VD5, VD6, VD7. Unfortunately the same way the instrument responds to the iron ******s from large surface area (eg, tin). This is due to the fact that the impact on the search coil in metallic ferromagnetic facilities arises directly two effects - the effect of conductivity and ferromagnetic effect. At a certain ratio of surface area to volume of the ****** begins dominate the effect of conduction.
- When closing the switch S1 the device switches to dynamic mode. This mode, the coil must move above the ground at a speed of approximately 0.5-1 m / sec. ******** of the ****** in the dynamic mode is the method "Artillery forks" during the coil over the target twice - on the left right and right to left. In this mode, it is important to feel the lowest speed which you can move the coil. This is easily mastered with a brief training. Indication in the dynamic mode is a little different.
- With filter N1: when moving the coil over a ferromagnetic ****** first ignited LEDs from the "scale" VD5, VD6, VD7, and then from the "scale" VD3, VD2, VD1. When moving coil over nonferromagnetic ****** display is contrary.
- With filter N2: Mndikatsiya similar to the static display mode. Ie for ferromagnetic ******s LEDs light up only of the "scale" VD3, VD2, VD1, and for nonferromagnetic - Only the "scale" VD5, VD6, VD7.
- As already indicated above, each LED has its own tone sound indication. After working with a metal detector to remember "tunes" that are characteristic for different types of targets. This allows for searching use mainly audible indication that quite comfortably. Before working in both modes should exhibit optimum sensitivity of the device using the variable resistor R6. He exposed in a situation where the device begins to indicate the false feedback. Then slowly turning the rotor of this resistor, it is necessary to achieve the disappearance of these false positives.
- All other things being equal, the dynamic mode by filtering allows achieve better sensitivity compared with the static mode. However static mode as it is sometimes necessary. For example, you should check bottom of the narrow hole. In this case, there is no possibility to horizontal rocking search coil, which are necessary for the dynamic regime. Here It can be applied static mode.
- Beginning with firmware version 5.1 the opportunity of the regime "Iron Mask". In this mode turns off the sound idikatsiya for iron ******s. This avoids the irritating sound plays frequent indication when looking at the garbage iron sites.
- Answers to questions (FAQ)
- Answers to questions (FAQ)
- Q1 What is the difference filters N1 and N2 in the dynamic mode?
- A1 With the first filter device has a slightly greater sensitivity the second - a more convenient display, which allows the use of "iron mask".
- Q2 Tell what is the frequency of the generator and construction features of the coil.
- A2 For practical reasons it is recommended to use the frequency in the range 15 ... 25 kHz. At the start of the microcontroller adjusts to the frequency of the search generator. To generator steadily worked, the ratio of the capacitors C1 and C2 should be close to (4 ... 6): 1. For example, when 47nF capacitors C1 and C2 10nF frequency generation will be about 17kGts. These capacitors should have a good TKE, especially C2!
- The coil is as follows: 100 turns of enameled wire, rolled back in ring diameter of about 200mm. Wire diameter 0.3-0.5mm. The entire coil should be placed in the electrostatic shield. The screen can perform wound coils of foil. The coil should have a mechanical stiffness. One of the ways -- fill it with epoxy.
- Q3 What is the procedure for setting the device?
- A3 We can suggest the following procedure for setting the instrument:
- 1.Proverit correct installation scheme.
- 2. Make sure that pin 3 Products D1 is present meander estimated frequency (about 17kGts for the above nominal capacitor C1 and C2 and the standard sensor). If the waveform is different from the rectangular, you must pick up a resistor R1 in the range of 0.2-1.5 kOhm
- 3. Measure the current consumption. It should not be more than 20mA.
- 4. Remove the device away from metal ******s and click Reset S0.
- 5. Ensure efficiency authorities indicating the sensor putting the various target.
- 6. Choose an optimal sensitivity of the rotating rotor variable resistor R6