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Quasar ARM - firmware update. Modernization of the Quasar Arm metal detector circuit with quasar arm discrimination




DIY metal detector Quasar ARM


Metal detector Quasar ARM is a balanced selective metal detector with metal discrimination and an LCD screen. Quasar AWP is a continuation of the project of a metal detector based on the AT Mega32 microprocessor “Quasar AVR”. The updated device circuit uses a more powerful ARM32 microcontroller and implements additional features, which will be described below.

Technical characteristics of the Quasar ARM metal detector:

  • Power supply 6-9 V
  • The operating principle is single frequency, IB.
  • Operating frequency – from 4 to 20 kHz;
  • Indication - multi-tone audio and visual LCD screen
  • Coin detection depth 5 kopecks. USSR (with 23 cm DD coil) – 30 cm.

  • Electronic compensation to eliminate coil imbalance.
  • FM modulator for wireless headphones
  • Coil current control unit
  • Self-diagnosis of the device when turned on

Schematic of the Quasar ARM metal detector

Printed circuit board Quasar ARM


This board is made for surface mount elements (SMD), which significantly saves time and money for the manufacture of the Quasar ARM metal detector. The board has cutouts for installing coil and power connectors. The dimensions of the board are designed to fit the very common Gainta 1910 case

List of parts for Quasar workstation



Instructions for assembling the Quasar AWP board from the author of the board

Metal detector board Quasar ARM rev.05a designed for self-assembly of the Quasar ARM selective metal detector. The scheme differs from the author's in some modifications:

  • Protection against polarity reversal of the power connection has been improved taking into account the minimum voltage drop in this node.
  • There is an electronic power switch off the device from the front panel with a button. When turned off, the metal detector does not consume current, thereby eliminating consumption when the device is turned off.
  • The display is powered from a separate voltage stabilizer; the display supply voltage level of 3.3 V or 5 Volts is selected by the type of voltage stabilizer installed.
  • The board has the ability to assemble a current control unit in the search sensor
  • The board has the ability to assemble an FM transmitter unit for connecting wireless headphones
  • The board is designed for installation in a factory-produced Gainta G1910 case

Do-it-yourself quasar workstation board assembly

The payment is collected in several stages:

1) Assemble a protection circuit against polarity reversal of the battery, a power supply circuit, and solder the power stabilizers. Check the functionality of the assembled components. Power management: briefly press the power button - the power turns on. Press and hold the button - the board's power is turned off.

2) Assemble the rest of the device, wash the board using special means or an ultrasonic bath.
3) Flash the STM32 processor via USART or SWD interface.
4) Connect the display, turn on the device, adjust the screen contrast
5) When installing an FM transmitter, the sound automatically switches to it; you must turn off the FM transmitter in the settings menu to output sound to the speaker.
6) Connect the device to the search sensor, configure it, check operation.

Some nuances when assembling the board:

Jumper JC2 shorts when


  • You do not install an FM transmitter on the board or the selected firmware version is lower than 2.2.2, in this case, if you do not install jumper JC2, no sound will be output to the speaker


Jumper JC1 is shorted when:

  • You are not assembling the current control unit in the search sensor (circled with a yellow marker), and you need to install a stabilizer (green marker) LM1117-5.0 and a 10 Ohm resistor R10, in the case when the unit is assembled you need to install LM1117-ADJ and R10 5, 1 Ohm


Display Power Stabilizer:


  • For a regular LCD display, it is recommended to install a stabilizer LM1117-5.0, for an OLED - LM1117-3.3

Mounting the display on the metal detector board


Elements of an FM transmitter V are highlighted with a yellow marker, elements indicated by a green arrow must be sealed in any case.

Assembly into the case and mounting the board:

  • Install the board on the back of the case and mark the holes, drill holes for I eat power supply and coil connections
  • Paste additional stands according to the selected height 3 or 2 mm
  • Install connectors and speaker
  • Install and secure the metal detector board


  • Cut holes for the display and buttons according to the drill in the top cover. The hole for the headphone jack is marked according to the fact

Quasar ARM- this is one of the most popular metal detectors, the circuit and firmware of which are freely available on the author’s website, for which special thanks to him. The capabilities of this device bring it to the same level as many commercial and expensive models. The author is constantly improving his creation and from time to time releases new firmware, each of which gives the device new capabilities, increases its stability and accuracy in determining the type of metal. In this article I will tell you how to update the firmware of a metal detector using my device as an example.


So, if you are the lucky owner Quasar ARM and want to update it with new firmware, carefully read the instructions below.
As you know (or don't know), the brain of a quasar is a microprocessor STM32F100C. And no matter how much we would like to reduce the complexity of its firmware to a minimum, we still need a special USB-TO-TTL programmer Of course, you can assemble it yourself, but it is best to buy it or borrow it from a friend. Such programmers are sold in radio stores. Personally, I took mine to Aliexpress. For specifics, I provide photos No. 1 and No. 2, in which the required programmer is shown on both sides.



Photo No. 1 - programmer - top view



Photo No. 2 - programmer - bottom view


Once you have the programmer in your hands, you need to properly pair it with the operating system. I have it installed on my computer Windows 10 and I admit, I had to rack my brains a little to achieve a positive result in this direction. So, if you haven't saved up either MAC and use standard Windows, do the following: insert the programmer into any port USB computer and go to the task manager to see how it is identified in the system. Most likely you will get something like the following picture (photo No. 3).



Photo No. 3 - problem when identifying the programmer


From the above photo you can see that Windows identified the programmer and assigned a virtual port to it COM9. However, a small exclamation mark next to the device name indicates a problem with the driver and, as a consequence, the current inoperability of the programmer. This can be fixed by installing a special driver, which I managed to find on the Internet not the first time. So, download the driver from this link: (downloads: 306)
Next, unpack the archive and get several files, as in photo No. 4.



Photo No. 4 - unpacked archive with drivers for the programmer


We launch the executive file from the archive and wait for the installation to complete. After which, we return to " device Manager", find the line with the name of the programmer (Photo No. 3), hover the mouse cursor over it, press the right button and select " Update driver"The system will offer to install the driver automatically, or from a specified location on the computer - we are inclined to the second option, not forgetting to specify the folder with the unpacked archive, as in photo No. 5.



Photo No. 5 - selecting a folder with drivers


Most likely, after pressing the button " OK", you will be asked to install one of 2 drivers to choose from. You must select the one with an older version, as shown in photo No. 6.



Photo No. 6 - installing an earlier version of the driver


Click " Further" and wait for the process to complete. Now the programmer should be correctly detected in the system. To check this fact, reopen " device Manager" and pay attention to the line where there was an exclamation mark. If everything went well, it should disappear, as shown in photo No. 7.



Photo No. 7 - correct identification of the programmer (no exclamation mark)


So, the programmer is installed, all that remains is to configure it correctly. Right-click on the name of the programmer in " Device Manager" (photo No. 7), in the drop-down menu select the item " Properties" and in the window that opens, go to the tab " Port Settings". Here you can configure the port speed and the algorithm for communicating with the program through which in the future we will flash our processor. Set the values ​​​​in accordance with the photo No. 8 below.



Photo No. 8 - correct programmer port settings


From this moment on, the first and most unpleasant stage is completed. The only advantage is that it only needs to be done once. For subsequent firmware upgrades, programmer configuration is not required. Now let's decide on how to connect the programmer to your metal detector. In most cases, special pins for connecting the programmer are routed and labeled on printed circuit boards. In my case, the pins were soldered, but not labeled. It looked something like this (photo No. 9).



Photo No. 9 - unnamed programming connector


If you have a similar situation, then you should pick up a tester and call everything according to the diagram below (photo No. 10).



Photo No. 10 - programmer connection diagram


In this diagram, I depicted a way to connect the programmer to a microprocessor, regardless of the type of printed circuit board on which your Quasar ARM. This is the classic way of programming UART interface. A few explanations about the diagram. IN 99% cases you will have a microprocessor in the case LQFP48. The numbering of its contacts begins with a small round icon and goes counterclockwise. For clarity, all the necessary contacts are labeled on the diagram, indicating their numbers in brackets. Pins RX, TX And VSS microprocessor are connected directly to the programmer. Conclusion BOOT0, serves for translation STM32 into programming mode. To enter this mode you must close BOOT0 with power output VBAT, otherwise the processor will simply start and operate normally. Later I will give a specific sequence of actions so that there is no confusion in your head.
We've sorted out the connection - you can download the software for programming. Typically microprocessors STM32 programmed using a special proprietary program Flash Loader Demonstrator. It is free and is available on the company's official website. Installation should not cause any difficulties, so I will leave this point without attention. Next, go to the author’s website and download the latest firmware version. At the time of writing this article, the latest version is 2.3.3 , as evidenced by photo No. 11, but I prefer the more stable version 2.2.18 .



Photo No. 11 - the firmware I selected for recording in MD


The downloaded archive must be unpacked and extracted from it the file with the extension .hex. This is the binary firmware file. Now you can move on to the final and most important stage.
First of all, we connect the programmer and close the output using a jumper BOOT0 And VBAT microprocessor. Insert the programmer into the port USB and supply power to the metal detector. If there is nothing on the screen, then we are on the right track and the microprocessor has entered programming mode. At the moment you should have a picture approximately like the one in photo No. 12



Photo No. 12 - jumper is closed, the programmer is connected, power is supplied




Photo No. 13 - connection settings


These are the connection settings by UART protocol. The indicated numbers must correspond exactly to those we set in the programmer port settings window (photo No. 8). Parameter Port Name- name of the virtual port assigned Windows programmer. It will probably be different for you. This name can be seen in " Device Manager" using photo No. 7 as an example. When all the settings are set, click " Next" to move to the next stage (photo No. 14)



Photo No. 14 - the program saw the microprocessor

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 they give a general idea of ​​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 the 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 look beautiful. 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 - Koschey 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.

TO vazar 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.

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.

This metal detector has medium difficulty level , for DIY playback! 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. Also, a big bonus when making it is a large number of discussions on the Internet, where a lot of questions have already been discussed!

Improvements in the new Quasar AWS:

· Removed external ADC, which was difficult to acquire.

· Increased sensitivity.

· Frequency range from 4 to 16 kHz.

· Improved sound quality.

· Added three profiles for saving and restoring settings (A, B, C).

· Electronic compensation has been introduced to eliminate coil imbalance.

Schematic of the Quasar ARM metal detector

Download diagram and parts list for the Kvazar ARM metal detector -

Printed circuit board of the Quasar AWP metal detector

Archive with printed circuit board quasar workstation -

Board with screen for Quasar AWP metal detector

For the Quasar AWP metal detector, you can use RC1602A screens with an HD44780 or KS0066 controller.

After making the board for the Quasar AWP metal detector, you need to flash the microcontroller. To program the microcontroller, you can use the st link v2 programmer (it is available in online stores), but for those who have a COM port (a big luxury these days), you can use a simple programmer on your computer according to this diagram (The diagram is taken from here - http://forum.cxem.net/index.php?showtopic=144107&st=20):

Firmware for the Quazar ARM 2.1.2 metal detector (latest at the time of writing) –

Archive with firmware for the Quasar ARM metal detector and a description of their changes -

After flashing the metal detector, it is necessary to carry out test runs and begin manufacturing the search coil.

Operating instructions for the Quasar ARM metal detector -

I found this video description of the manufacturing process of the block and coil of the Kvaraz AVR metal detector:

Part 1, starting with the board

Part 5, let's move on to making a coil for the Quasar metal detector

Part 12, completion and fine-tuning


Conclusion: Quasar ARM is a decent mid-level metal detector. If manufactured correctly, it may well compete with branded analogues. The main purpose of a metal detector is to search for coins. The circuit does not contain expensive and scarce components, but has a number of technological nuances and is demanding on the quality of coil manufacturing. To repeat it, it is recommended to “have” experience in similar products, otherwise the result may disappoint you!

Materials used when writing this article:

· Forum Scheme.net - http://forum.cxem.net/index.php?showtopic=144107&st=0

(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 generator, or rather the Tx drive 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 mini device 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)