(scheme upgrade)

Metal detectorQuasar-ARM, one of the most popular digital devices today.

This one is very good, and you can verify this by typing the corresponding name in an Internet search or on YouTube...

And yet, of course, the device has weak points, which we will modernize.

Let's start with the device diagram.

Let's start with upgrading the device's generator, or rather the Tx boost circuit.

The signal from the microcontroller through resistance R17 1 kOhm is sent to a level matching circuit made on BC846 transistors, then the signal goes to a circuit similar to the Mosfett “driver” (controlling the opening and closing of field-effect transistors in the IRF7105 assembly)…

Everything seems to be fine, everything works, we see satisfied users. But the problem is that the parts market does not always offer us good and cheap elements. Often this is unreliable China, and most importantly, if you buy a cheap device (cheaper than competitors), then this means cheap components.

So, this unit has already failed 3 times in my experience. It was necessary to change the BC846 transistor, and it also came to replacing the IRF7105 itself.

More than a dozen elements work in this unit, which means that the possibility of failure of at least one of the 10 elements is fraught with failure of the entire device.

What to do?

There are several options. One of them is to pass the signal from R17 through the 74NS14 microcircuit element. This is how cascades of devices such as Groza or Anker and others work. They have been working for many years and no complaints.

But how justified is this? What if this is not quite the right step?!

Well... after looking through the information on the Internet, I, with the help of my good friends, found a specialized microcircuit - TC4420 (possibly similar to it).

This microchip in the SOIC-8 package already contains both a driver and a field assembly for a load of up to 1.5 Amps!

The result is 1 micro-piece instead of 10 parts. Everything ingenious is simple!

Scheme of the modified cascade.

You can, of course, not stop there and painlessly throw away C4, VD2, VD3, and also replace resistor R2 (10 Ohms) with an acceptable current in the Tx coil (up to 1-2 Ohms). Then the current in the coil will increase...

However, experiments with R2 have shown that the sensitivity of the device when the Tx coil current changes from 50 mA to 80 mA increases by only 3-5 cm, per 5 kopeck USSR coin. But the gluttony of the device is increasing, which means the batteries will discharge faster...

There's a lot to think about here. To begin with, the sensitive part of the receiving amplifier U1A is sensitive to everything on both inputs (legs 2 and 3). So the quality of the signal (reference voltage) must be perfect.

But as always, not everything is as perfect as we would like. Often now on the market of radio elements the MCP6022 microcircuit is made in China and is of dubious quality. It exhibits the following “symptoms” - noise at the U1B output, up to saturation (+3.3 Volts). Moreover, the device works perfectly if it works for no more than 30 minutes to 1.5 hours. And damage occurs during long-term operation.

Everything falls into place if you warm up the microcircuit (for example, with a soldering iron 8 leg MCP6022 (+3.3 Volts). But this is only a temporary salvation, because

The solution to the problem is to replace the Chinese MCP6022 microcircuit with an AD8606 (American company Analog Devices), or a real MCP6022 from Microchip.

The second problem with this unit is the 10 µF SMD capacitors. Which are often so bad that they cannot even hold that voltage (1.65 Volts) and over time or immediately fly out, simply turning into a resistor.

The solution is to replace it with SMD tantalum polar capacitors in the required size.

Changes to the “correct” sensor of the device are still only in process... The rest has already been tested and works.

And finally... minor changes in the circuit that can be ignored.

You can remove unnecessary nodes for programming from the boards, leaving only one (I use SWD), as well as a circuit for adjusting the contrast on the LCD screen - if you use OLED screens.

Photos - before and after the changes.

Good luck to everyone in instrument making and searching. Let your Quaza-ARM will bring you cool finds and mood!

Alexander Serbin (Kharkov)

The Quasar Arm metal detector (quasar arm in English) is a selective, IB device created and designed by Andreev Fedorov, aka Andy_F. This device became a continuation of the Quasar line on microcontrollers, in this case on the controller of the STM32 family.

In this article we will look at its characteristics, field tests and consider the materials that we may need if we want to make it ourselves. Many people are still interested in this question: does it distinguish between metals? But here it is noticeable to the naked eye that the quasar arm metal detector is discriminatory.

Technical characteristics of Quasar Arm:

• Supply voltage – from 6 to 15 volts.
• Current consumption is on average from 150 to 200 mA, depending on the settings.
• Multi-tonality is present.
• Sector masks are present.
• Operating modes – dynamics and statics.
• Operating frequency - it all depends on the sensor, from 4 to 20 kHz.
• The operating principle is single frequency, IB.

These are not all the characteristics, but general idea They give information about the device. If you haven’t turned around yet and are ready to assemble a quasar arm with your own hands, then let’s look at what we need to assemble it.

Quasar arm diagram

Let's talk about the quasar arm md circuit, it will be provided below. In general, this is a rather complex device and it is not suitable for beginners; you need to understand the processes and have soldering experience. This is what the quasar arm circuit looks like:

By the way, we are enclosing a list of parts for this device, save it so you don’t lose it.

Quasar arm board

Now let's talk about printed circuit board, it looks like this:

Well, there’s nothing to say here, download, print and etch. Note that some are interested in ordering boards from China. There is such an opportunity, there are manufacturing plants on Aliexpress, just write to them in a personal message, send the fee to.lay, pay and wait until they send it. The boards are made using professional equipment and are of decent quality. The disadvantages of this method are that most do not work individually (I got 5 or more pieces), and the price for a large quantity is already quite high. But if you order for sale or with friends, then there is no problem.

Coil quasar arm

So we moved on to the moment of making a coil for the Quasar Arm metal detector, it was decided not to describe everything, but to show a video. Because it’s better to see once than to hear 100 times, or in this case, read. This 20-minute video tells how to make a sensor with your own hands, how to connect a coil and much more, there are also useful comments under the video.

Here is the diagram, it is the same as in previous versions of the device.

Setting up quasar arm

Now let's talk about what the settings of the Quasar Arm metal detector are. The device will simply not work, or will not work correctly. You need to make settings, of which there are a lot, and you also need to be able to calibrate the device and adjust it to the ground.

This is all a long song, if I describe everything. And again I remember the saying about what is better to see once. So we are putting together a fairly detailed video about its settings.

This video is from a fairly competent person who assembles these devices. And there is no point in describing every point of its configuration, it’s a monkey’s work in general. If you can't set it up, watch this video. We talked about setting up the MD quasar, learned how to set it up, and moved on.

Quasar Arm firmware

As for the firmware, the current version is 2.2.3, if you need an earlier version, visit the author’s website. Now about how to flash a quasar arm. Let’s attach a video, this is of course an older firmware, but the principle is the same, there’s nothing to describe here either.

Quasar arm block

You can make the block yourself by making it from any beautiful box. They also sell ready-made boxes for quasars, they are made to size and have beautiful view. Good blocks are sold on Chinese websites, there is also quite a large selection there. Here is the sticker for the device:

So, we disassembled the block of the Quasar Arm metal detector and moved on.

Quasar arm instructions

This is not a simple device and you can’t do it without instructions. In the instructions you will find troubleshooting, answers to many questions, for example: repair of the quasar arm, problems with weak sensitivity and input amplifier, information on the quasar arm with FM and other malfunctions of this metal joker. Also, if the video is not enough for you, then there will be information on the Quasar Arm menu.

Quasar Arm metal detector reviews

I believe that if you read this article, then everything is clear. A good and high-quality unit is this Quasar arm. Of course, there are some nuances, but in terms of parameters it surpasses many industrial units. I would like to note that if you purchase a ready-made device, then be very careful about the choice of the contractor. Because the quality directly depends on the assembly, and the prices for this device vary from manufacturer to manufacturer. We do not recommend buying from those who sell used or individual circuits (not a store or a master), you may be left without support if the seller disappears. Find those who have a lot of reviews.

Quasar arm video

Here are a couple of videos from the quasar arm, here is a cop with it and a video of tests. Take a look and decide if you need it. Also a comparison video - Koschei 25k vs Quasar Arm.

So we figured out how to make a Quasar Arm metal detector with your own hands, I hope the article was useful for you.

The FAQ section was created for the convenience of obtaining basic information about metal detectors. Here you can find a description of how to configure, video instructions, diagrams, etc. Answers to frequently asked questions. We recommend that everyone who is interested in this or that device start by studying the information in this section. You can fill out information in this section by contacting the administrator. We welcome the participation of each forum participant. As the section is filled with information, each of us will be able to more fully study the device of interest, its capabilities and characteristics, and receive informational assistance as a foundation for subsequent successful development and maximum effective use.

• Quasar workstation

• Quasar ARM is a selective metal detector with an LCD screen and the distribution of metals into 16 groups. This is a continuation of the Quasar metal detector project. The new circuit uses a more powerful ARM32 microcontroller and adds additional features. This metal detector has an average level of complexity, so you can reproduce it yourself! Only people with experience should undertake its production. There are SMD components (which can cause difficulties for a beginner), a programmable microcontroller, and a coil for an IB metal detector, which also causes a lot of trouble if you don’t have the proper experience. But if all these nuances do not bother you, then the device will pleasantly please you!

  Technical characteristics of the Quasar ARM metal detector:

  • Operating frequency – from 4 to 16 kHz;
   
  • Indication - multi-tone audio and visual LCD screen.
   
  • Power supply – 12 volts.
   
  • The detection depth of a 5 kopeck USSR coin (with a 23 cm DD coil) is 30 cm.
   
   

  Improvements in the new Quasar AWS:

   
  • Removed external ADC, which was difficult to purchase.
   
  • Frequency range from 4 to 16 kHz.
   
  • Improved sound quality.
   
  • Three profiles have been added to save and restore settings (A, B, C).
   
  • Electronic compensation has appeared to eliminate coil imbalance.
   
     

Metal detector « QUASAR- ARM", a modern digital IB metal detector, assembled on a fairly new and modern STM32 controller.

This one has many useful features and menu device settings.

What’s very nice is the use of a wide range of operating frequencies (one to choose from, auto-selection of frequencies to resonate with the search sensor, etc.), as well as 8 user profiles (which can be saved or called up from the menu).

Despite my skepticism towards digital metal detectors, after the first time I used it, I practically “fell in love” with it. What I can’t say about many branded devices!!!

Technical characteristics of the Quasar AWP metal detector with a DD-20 cm search sensor:

Coin with a diameter of 25mm (ground)…. up to 35 cm

Helmet…………………………………….. up to 1.2 m

Maximum …………………………. up to 1.7 m

Sound indication to choose from...... from 2 tones or more

Visual indication VDI………….. yes

Installation of masks on types of metal...... yes

Operating principle……………………….. IB (inductive balance)

Sensor diameter………………………… from 15 to 30 cm

(optional)

Operating frequency range……………. 6 to 20 kHz

(depending on firmware)

Supply voltage………………… 3.7-5.5 Volts

Current consumption……………………… about 100-180 mA (depending on settings)

Here is a view of the assembled device board (photo below).

...I didn’t want to make a board, as in other things, I didn’t want to buy a completely finished device, so I limited myself to buying an empty board from This e-mail address is being protected from spambots. You need JavaScript enabled to view it.

(with a soldered-in firmware controller). Fortunately, this is now very possible and at divine prices.

The circuit diagram of the device turned out to be very simple and I decided to assemble and configure this device myself. I had all the necessary equipment for this.

The assembled board looked like this...

Assembly and configuration were facilitated by some files kindly provided This e-mail address is being protected from spambots. You need JavaScript enabled to view it.

...

You can download all this, as well as instructions for the Kvazar-ARM detector.

A short video about the modes, operation and configuration of the sensor:

Well, now about my impressions:

Assembly was short and very pleasant, since the board was made at the highest level (mask, numbering of parts and seats).

The device started up immediately and obeyed the keyboard commands;

After manufacturing the 20 cm DD sensor, the device (or rather its software capabilities) helped in setting up the sensor...

With a 20 cm sensor it showed good results and target selection;

In a sealed plastic case, tested under immersion conditions (chest-deep).

Well, in conclusion, I want to say: “I have not yet held the best domestic device in my hands!”

I haven’t had a chance to use the Quasar AWP in salt and sea conditions (and I have doubts until I try it personally)…

Well, for these purposes (sea search), I am assembling another device for myself. Well, for those who want to have such a device, but are afraid to assemble it themselves, I am always ready to help.

This e-mail address is being protected from spambots. You need JavaScript enabled to view it. .- Metal detector QUASAR

Alexander Serbin (Kharkov)