Recently, quality metal detector modules have appeared on the market for a very low price. Almost no knowledge of electronics is required to make the final product. This time I will present you one such module and I will try to briefly capture its features. 

The module is sold under the name "Impulse III", and its price on Ebay is about 35 dollars. It arrived nicely packed, and protected from mechanical damage, very quickly in about 15 days from Kazakhstan to Macedonia. The device is compact and solidly built and the main panel is only slightly larger than the LCD screen. On the front there are two large buttons through which we perform all the necessary settings.

  As I mentioned before, in order to put the metal detector into operation, it is necessary to solder only six wires, two from the power supply, two from the speaker, and two from the coil. The supply voltage should be around 12 Volts (3 or 4 Lithium batteries connected in series, or one Lead battery 12 Volt). Let me mention that it is very important to pay attention to the polarity of the battery, because in case of a mistake it is very easy to permanently damage the device.

  The coil is identical to the one I use in my DIY Pulse Induction Metal Detectors, and This coil dimension represents a kind of compromise in relation to coils specialized for detecting small objects (which are mostly of smaller diameter), and those made for detecting larger massive objects at a greater distance (in these the diameter can be 1m or more ).

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  The detector worked immediately after switching on, but only required some adjustment.  

  It is necessary to press "B" button after switching on, as well as in case of

signal drift, increased noise and false positives. To enter the settings menu, you need to hold down the "A" button for a few seconds. Further, the buttons "A" and "B" are used to select a category, after which it is necessary to hold down the button "A" for several seconds. Now you can change the parameters of the current menu item. To exit the current menu item, hold down the "B" button for a few seconds. To return to the main (working) screen, you need to hold down the "B" button again for a few seconds. 

  As in the previous review for the Clone Pi-W Metal Detector, I am really pleasantly surprised by the features such as sensitivity and stability in operation, considering that it is a very inexpensive module, and to make a complete mid-range metal detector we need almost no knowledge from the field of electronics. This time I would like to emphasize that the results were a little better, but in real conditions, in moderately wet soil, many false alarms occur, so to avoid that, filters are used that also slightly reduce the sensitivity. Thus, the final result when comparing these two metal detectors is almost identical.

  All we have to do is solder a few wires, and the only thing is to be very careful about the polarity of the battery.