SELECTIVE METAL DETECTOR SPECTRUM

SELECTIVE METAL DETECTOR SPECTRUM

Modern industry offers a huge selection of various equipment for carrying out work on searching for metal objects in the ground, walls, water, etc. No fewer (if not more) different schemes are submitted to the public by amateur authors. Some author’s works have absolutely no analogues among factory devices, but still most of the homemade designs have units and blocks copied from devices of well-known manufacturers, but brought by amateurs in parameters almost to perfection. One of such devices will be discussed in our article. The Spectrum metal detector , developed by Konstantin Saveliev , is an improved reworking of the well-known at one time microprocessor device Koschey 18 designed by Kolokolov-Shchedrin. Below is a schematic diagram of the device with all the adjustments and additions made by the author. The archive contains a list of the main parts of the circuit.

Spectrum metal detector diagram

The main highlight of the unit is its unique firmware, which has made it possible to implement an extensive service for controlling the device, as well as an indication of search modes, such as a hodograph , the presence of which is welcomed by some search engines not only as a visual search gadget for more accurate determination of the material of the search object, but also as a reference to the branding and high-class quality of AKA devices

Brief technical characteristics of Spectra

• >> Two search frequencies – 7000 and 14000 Hz.
• >>Search depth:

– 5 kopeck USSR coin in the ground – up to 30 cm
– pistol – 65-70 cm
– helmet – 1.2 meters
– sewer hatch – 1.5 meters

• >>The maximum sensitivity of the device is 2 meters.
• >>The sensitivity of the device to air is 5 kopecks – up to 40 cm, with a search sensor diameter of 275 mm.
• >>Works with 128*64 pixel displays, as well as with common displays from Nokia3310 phones.

The metal detector has a multi-tone sound indication, can operate in dynamic and static search modes, the dynamic discrimination mode is calculated and controlled by the processor program.

The Spectrum metal detector is equipped with a large LCD display, which displays information in the hodograph or spectrograph mode. Continuous operation time:

• – with a 1.0 Ah acid battery – up to 10 hours;
• – with a 1 Ah NiMH battery – up to 8 hours;
• – with a 2 Ah NiMH battery – up to 20 hours;

Unfortunately, the firmware of the device is paid. You can buy a firmware controller by writing to the author at kusav@mail.ru . You can also buy printed circuit boards separately or fully assembled and debugged boards with parts.

Next, let’s look at the steps after receiving the order by mail. So, unpack the parcel – let’s start assembling the device (if you ordered the controller and board) from the parts purchased separately according to the assembly drawing.

If you ordered an assembled board, you will only need to connect the graphic LCD indicator according to the diagram.

We make a printed circuit board for the buttons ( located in the archive ), and assemble it all together according to the diagram..

Next, you need to make the body of the device (or adjust the factory one purchased in the store), the battery compartment, and make or purchase a rod – that’s it, the device is ready!This MD has the ability to independently update the software. This allows you to load the latest version of the software into an already assembled metal detector. The MD program is constantly being improved based on user requests and suggestions. The Atmel “ AVR231: AES Bootloader ” is used as a bootloader. The necessary changes have been made to the circuit so that you can connect the Spectrum to a computer. To connect, you need to assemble this simple adapter circuit for the COM port.

You can find adapters on transistors on the Internet, without using MAX232 – it’s up to you. The firmware update sequence is as follows:

•  disconnect the sensor;
•  connect the COM port of the computer and the LCD connector of the metal detector
  using a cable with MAX232
•   download and run the update program from the author’s website (there you can also download the latest firmware versions), specify the correct COM port to which you connected the cable and the firmware update file;
•  press and hold the “ MENU ” button before turning on the MD. Turn on the MD;
•  the MD makes a short two-tone sound. Start the update process, if no errors are detected, the program will report a successful update download;
•  then turn the Spectrum metal detector off and on. Check the firmware version number on the display screen at the time the MD is turned on.

At the current moment, a version of the software for the resonant sensor has been developed (but this requires a small adjustment of the main circuit, so this is in another article). It remains to add that the author is constantly upgrading the software of the device, making amendments and adjustments according to the wishes of users, so you will not be left without technical support. All the necessary documentation is in the archive, and in the next material read about the manufacture of the search sensor . Easy searches and successful finds to you! The material was prepared especially for the site “Radio Circuits” – Elektrodych .