Pinpointer MINIMAX-PP-II

Pinpointer MINIMAX-PP-II

This device is a precise Pinpointer indicator for the exact location of the detected metal. The principle  working is very simple, for people looking for coins and small objects in the ground and  but can not buy a commercial pinpointer. This works well and many of its parts are available. In this post there is everything necessary to build it  from the diagram to printed circuit board PCB  that can be downloaded at the end of the post. 

Pinpointer MINIMAX-PP-II

According to the schematic of the device, I think there will be no questions or problems in the building, just all components should be installed on the printed circuit board PCB, paying attention to some details on the board that should fully comply with the schematic.

All capacitors used in the device must be film-type with an operating voltage of at least 100 volts.

Technical specifications  Pinpointer MINIMAX-PP-II

Pinpointer Minimax PP-2 is a simple, reliable and compact metal detector developed by a member of the forum on md4u under the name Petrucho. Tested on land and in water, works great in salt water and soil.

Let us know the technical characteristics of the device:

  • Consumption ……….. 18 mA;
  • Alarm signal. Sound (fixed tone);
  • Detection of coins ………….. 5 cm.

A short video an the end shows its performance characteristics.

The designer  of Minimax PP-2 gives a short description of the principle  working  so that it depends on the principle of measuring the quality coefficient Q. The circuit is very simple – only one chip and 4 transistors. The device can be powered by a battery of 3 to 5.5 volts (5.5 volts is the maximum voltage for MCP602 chip).
It is recommended to use  two AA or AAA batteries, or one 3V lithium battery (or 3.7V 18650 lithium battery).
The printed circuit board PCB can be made  from the schematic. But do not tire yourself because we will include them in the last post to download

According to original printed circuit board PCB, it is used on one side with a combination of normal components DIP and SMD .

Finally, some pictures of the collage.

Search coil for Pinpointer MINIMAX-PP-II

For the  coil L1 , you can use a piece of ferrite rod, a diameter of 10 mm removed from the magnetic antenna of an old radio  as shown in the picture.

The length of the rod is 10 cm, and the coil is made from 4 layers, with an insulated copper wire with a diameter of 0.35 mm. The total number of turns is 450. After the winding process, we squeeze the coil well so that it shrinks and doesn’t leave spaces between the turns.

After some experiments and verifying that the circuit is running properly, it is necessary to impregnate the coil L1  with epoxy or varnish. This will give the search file stiffer and more stable.
The pinpointer refers to an existing metal target with an acoustic signal. This sound is generated by a beep (a piezoelectric element with a built-in sound frequency generator) with an operating voltage of 5-6 volts.

Download files:

  1. PCB 1 with Sprint Layout 
  2. PCB 2 with  Sprint Layout 

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