EK-004A
Radio designer "Your radio" No. 4A. Controlled by Arduino
5237 rub.
FM radio receiver controlled by Arduino Nano - for the most advanced and purposeful. Arduino combines play and learning, allowing you to create something worthwhile and interesting. This platform empowers the creative person in the field of electronics, even if he knows nothing about it! With the help of Arduino, any humanist can become familiar with the basics of electronics and programming. The programming language for Arduino devices is based on C/C++. It is easy to learn, and at the moment, Arduino is perhaps the most convenient way to program devices on microcontrollers.
Specifications of EK-004A| Parameter | Meaning |
| Upit. constant, V | +4,5 ... 5,5 |
| Upit. nom. constant, V | +5 |
| Recommended power supply not included |
USB port PC with miniUSB cable, USB adapter with miniUSB cable, TGR-025, PW0530B ES18E05-P1J, GS15E-1P1J |
| Radio module type | MP1090S |
| Tuning range, MHz | 76…108 |
| Sensitivity, µV | 1,7 |
| Stereo channel separation is no worse, dB | 25 |
| Stations in memory | 3 |
| Microcontroller type | Arduino_Nano_V_3_0 |
| Output power, W | 2 x 1.5 |
| Speaker system power, W | 2 x 0.5 |
| Suitable for | MP1090 FM radio 65...108 MHz, MP1095 Real Time Clock (RTC), MP1094 IR remote control with receiver |
| Overall dimensions of the speaker system, mm | 80 x 80 x 80 |
| Overall dimensions, LxWxH, mm | 160 x 210 x 50 |
| Operating temperature, °C | 0...+55 |
| Relative operating humidity, % | ...55 |
| Production | Contract manufacturing in Russia |
| Warranty period | 12 months |
| Weight, g |
The “coloring” construction set allows you to show both technical and creative abilities, as a teenager can create his own design of a radio receiver. FM radio is assembled from ready-made modules, each of which represents a complete device. Requires soldering of 2 points (jumper). The Arduino Nano module is programmed with code that allows, after assembling all the modules into a single structure, to obtain a stereo radio receiver.
Structural diagram of EK-004A
EK-004A controls lighting LEDs
Frequently asked questions about EK-004A
I connected the EK-004A according to the instructions, but it does not work. In this case, only one white indicator blinks next to the constantly lit blue light on the microcontroller. What else is he missing?
- Please connect the Arduino module to the USB port of your PC.
- Go to Start --- Settings --- Control Panel --- System --- Hardware --- Device Manager --- Ports (COM and LPT).
- Make sure that the Arduino module is detected by the PC OS.
- Does your OS see the Arduino module? If yes, everything is in order, let's continue. If not, install the driver for the Arduino module. Read more about this http://arduino.ru/Guide/Windows
- Judging by the description, the Arduino module is clean, i.e. It does not have a radio receiver flashed into it. In this case, please follow these steps:
- Download the programming environment IDE Arduino 1.0.5 Windows Installer, Windows (ZIP file) from the page http://arduino.cc/en/Main/Software (also in Russian http://arduino.ru/Arduino_environment).
- Install Arduino IDE 1.0.5 on your PC.
- Download the Arduino library archives, for example, to your PC desktop from here:
http://masterkit.ru/zip/MP1090S.zip
http://masterkit.ru/zip/MP1091.zip
http://masterkit.ru/zip/MP1092.zip
http://masterkit.ru/zip/DS1307RTC.ZIP
http://masterkit.ru/zip/Time.ZIP
http://masterkit.ru/zip/PinChangeInt.ZIP
- Unpack the Arduino library archives into the arduino-1.0.5\libraries folder.
- Make sure that the relevant files are in the appropriate folder, i.e., for example, the files MP1091.h and MP1091.cpp should be located in the MP1091 folder, etc.
- Download the radio receiver sketch archive from the page http://www.masterkit.ru/main/set.php?code_id=1183334
- Unpack the sketch anywhere on your PC.
- Open the sketch by double-clicking the left mouse button on it.
- Click the button with a check mark (on the left) “Check”, after which the message “Compilation completed” appears.
- Connect the Arduino module to the USB port of the PC.
- Press the arrow button (next to) “Load”, after which the sketch is loaded into Arduino.
- Install the programmed Arduino with EK-004A and connect the power.
Getting started with Arduino is described in detail at http://arduino.ru/Guide/Windows
A description of Arduino programming is available at http://arduino.ru/Reference
Ready-made examples are available at http://arduino.cc/en/Tutorial/HomePage
A description of the Arduino programming language commands is available at http://arduino.cc/en/Reference/HomePage
Ready-made Arduino libraries for use can be found at http://www.henningkarlsen.com/electronics/library.php?id=34
We are all familiar with Christmas tree garlands consisting of multi-colored light bulbs. However, recently products based on LEDs have become very popular.
How they are designed, what kind of connection diagram they have and what to do if the garland stops glowing will be discussed in detail in this article.
What does a Christmas tree garland consist of?
What is a garland of LEDs, is it worse or better than a regular one?
Externally, this is almost the same product as before - wires, light bulbs (LED), control unit.
The most important element is, of course, the control unit. A small plastic box on which various operating modes of the backlight are indicated. 
They can be changed by simply pressing a button. The unit itself can be quite well protected with IP44 level of moisture and dust protection. 
What's inside? To open it, use the sharp tip of a knife or a thin screwdriver to pry up the latches from below and remove the protective cover. 
By the way, sometimes it is glued, and not just sitting on the latches.
First of all, inside you will see wires soldered to the board. The thicker wire is usually the network wire, supplying 220V voltage. 
Soldered on the board:
- the controller that creates all the lighting effects
- thyristors, each of them goes to a separate channel of the garland
- resistors
- capacitor
- and diode bridges
The number of board elements depends primarily on the number of light channels of the garland. More expensive models may have a fuse. 
LED garland diagram
The AC mains voltage is supplied to the power controller through resistors and a diode bridge, already rectified and smoothed through a capacitor. 
In this case, this voltage is supplied through the button, which is open in the normal state. When you close it, the controller modes switch.
The controller in turn controls the thyristors. Their number depends on the number of backlight channels. And after the thyristors, the output power goes directly to the LEDs in the garland.
The more such outputs, the more varied the colors the product can have. If there are only two of them, this means that only two parts (or halves) of the garland will work in different modes - some bulbs will go out, others will light up, etc. 
In fact, these two lines of diodes will be connected on two channels in series. They will connect to each other at the end point - the last LED. 
If for some reason you are annoyed by the blinking of the garland and you want it to glow evenly with only one color, it is enough to short-circuit the cathode and anode of the thyristor on the back side of the board using soldering. 
The more expensive the garland you have, the more outgoing channels and wiring will leave the control board.
At the same time, if you follow the traces of the board, one of the mains voltage outputs is always supplied directly to the final LED of the garland, bypassing all elements of the circuit. 
Causes of malfunction
Situations with garland malfunctions are very diverse.
At the same time, remember that the most important element - the microcircuit on the board - “burns” very, very rarely.
In approximately 5-10% of all cases.
- Poor contact on wires
- LED in one of the light bulbs
- Capacitor
- Resistance
- One of the diodes
- One of the thyristors
- Controller chip
Bad soldering
If your backlight suddenly stops working, first of all always check the soldering of the supply and output wires. It is quite possible that the entire contact was held only by hot glue. 
It’s worth moving the wiring and contacts as usual.
The most common problem with Chinese garlands is the use of very thin wires, which simply break off at the solder points on the board.
To prevent this from happening, all contacts after soldering must be covered with a thick layer of hot-melt adhesive. 
And when stripping such veins, it is advised to use not a knife, but a lighter. Instead of whittling away the insulation with a blade, lightly heat and melt it with a lighter. 
After that, simply remove the outer layer with your nails without damaging the veins themselves.
LED damage
If the wire contacts are OK and you are sinning on one of the diodes, how can you check if it is faulty? And most importantly, how to find it among the whole series of light bulbs? 
First of all, unplug the garland from the outlet. Start with the last diode. The power wire comes to it directly from the control unit.
An outgoing conductor is soldered to the same leg. He goes to the next branch of the light channel. You also need to test the diode between its two power wires (input-output). 
You will need a multimeter and its somewhat modernized probes. 
Thin needles are tightly tied to the tips of the tester probes with a thread so that their points protrude a maximum of 5-8mm. 
Wrap everything on top with a thick layer of electrical tape. 
Since the LEDs are soldered, you won’t be able to simply pull them out of the light bulb like in regular garlands.
Therefore, you will have to pierce the insulation of the conductors to get to the copper conductors of the wiring. Switch the multimeter to diode testing mode. 
And you begin to sequentially pierce the supply wires near each suspicious diode. 
If you have a garland not 220V, but 12V or 24V, which is connected from this power supply: 
then the working LED from the multimeter battery should light up. 
If this is a 220V backlight, then check the multimeter readings.
On working elements they will be approximately the same, but the faulty one will show a break.
The method is of course barbaric and damages the insulation, but it works quite well. True, after such punctures, it is better not to use outdoor garlands outdoors.
Chaotic blinking
There is a situation when you turn on a garland and it starts blinking chaotically, sometimes brighter, sometimes dimmer. It sorts through the channels on its own.
In general, one gets the impression that this is not some kind of factory effect, but as if the garland has “gone crazy.”
Most often the problem here is the electrolytic capacitor. It may swell and swell a little, and this will be clearly visible even to the naked eye. 
Everything can be solved by replacing it. The denomination is indicated on the case, so you can easily purchase and select a similar one in radio parts stores. 
If you replaced the capacitor, but it did not give any effect, where to look next? Most likely one of the resistors has burned out (broken). It is quite problematic to visually determine the breakdown. You will need a tester.
You take resistance measurements, having previously learned its nominal (normal) value from the markings. If it doesn't match, change it. 
Part of the garland does not shine
When any of the channels on the garland does not work completely, there may be two reasons.
For example, a breakdown on one of the thyristors or diodes responsible for it.
To make sure of this for sure, simply unsolder the wiring of this channel on the board from its place and connect there the adjacent channel, which is known to be working. 
And if at the same time another channel also stops working, then the problem is not in the garland itself, but in the components of its board - a thyristor or diode. 
You check them with a multimeter, find the ones that match the parameters and change them.
The garland shines dimly
There are also not entirely obvious accidents, when the LEDs of a separate channel seem to be on, but rather dimly compared to the others. 
What does it mean? The controller circuit is working fine. When you press the button, all modes are switched.
Testing the parameters of the diode bridge and resistance with a tester also does not reveal any problems. In this case, the only thing left to blame is the wires. They are already quite frail, and when such a multi-core wire breaks, its cross-section decreases even more.
As a result, the garland is simply not capable of starting the LEDs in the nominal brightness mode, since they simply do not have enough voltage. How to find this torn vein in a long garland? 
To do this, you will have to walk along the entire line with your hands. Turn on the garland and start moving the wires near each LED until all the backlight lights up at full strength.
According to Murphy's Law, this may be the very last piece of garland, so be patient.
As soon as you find this area, pick up a soldering iron and disassemble the wires on the LED. Clean them with a lighter and solder everything again. 
Then insulate the soldering area with heat shrink. 
Among the many lighting devices used to decorate New Year trees, the Chinese garland design occupies a special place. It, like all similar Chinese products, is simple and cheap. There is a lot of controversy about the reliability of such garlands, however, most consumers use them.
Diagram of a classical Chinese garland
This design is equipped with smooth brightness control. For this, phase control is used to regulate the opening angle of the thyristors. Automation uses as many as eight programs that provide a wide variety of control algorithms. Due to its qualities, the device is very cheap, which is why it sells in millions of copies.
The controller is based on a small board with space provided. A microcontroller with four outputs is also located here. It is a small piece of genitax, where a microchip is attached using epoxy resin. Through the outputs of the microcontroller, using current-limiting resistors, four thyristors are controlled. This device is designed for anode voltage up to 600 volts and a current in the range of 0.6-0.8 amperes. In some designs of cheap garlands, instead of the input diode bridge, one diode remains. At the same time, the electrodes that control the thyristors are connected directly to the microcontroller outputs, without limiting the current.
As a rule, the power of the microcontroller is very small, therefore, it is not able to control the operation of powerful triacs. In order to solve this problem, it is necessary to use a separate low-power power source that is galvanically isolated from the general network. For these purposes, you can use a low-power adapter, for example, one that powers a television antenna amplifier that contains a stabilizer in its circuit.
Other ways to solve problems
To combine a low-power microcontroller with powerful triacs, it is practiced to use transistor switches, where transistors with a high current gain are used. Thus, the Chinese garland circuit does not overload the microcontroller outputs. To ensure galvanic isolation, special microcircuits are used, the input of which contains an LED, and the output has a low-power triac.
In order for the Chinese garland to work normally, it must be synchronized with the network using a signal. For this purpose, a phase with a nominal value of 220 volts is supplied to the input of the microcontroller through an installed resistor. The neutral wire of the network is connected to the common wire of the entire device.
Replacing the Chinese garland control unit
Almost every family has a broken Chinese New Year garland that needs repair. December always comes and takes families by surprise, who just the day before decide to put up a New Year tree and decorate it with beautiful garlands.
As a rule, we find out that a Chinese garland needs repairs at the wrong moment. You don’t want to spend money on a new thing, but not everyone can repair a Chinese New Year’s miracle on their own.
Now we will look at how a simple Chinese garland with adjustable light frequency works, common faults, methods for troubleshooting and ways to eliminate them. In the article everything will be described in detail, clearly shown in photographs. Everything will be convenient for restoring its functionality on your own. Almost every person will be able to cope with such repairs.
Schemes of New Year's garlands
Serial connection of paws
First, let's look at the simplest scheme of a New Year's garland. This series connection of incandescent light bulbs was the most common scheme in the Soviet years. Every house had a similar garland.
In a series connection, all the light bulbs are connected in a chain, in a wire break, and connected to a power source, generator, home wiring, battery. In this case, the same current flows throughout the garland.
There was no smell there, of course. She was forced to blink by starters taken from fluorescent lamps at school. The starters were simply connected in a circuit, similar to light bulbs, in series.
A few words about starters and their meaning. This is a simple gas-discharge lamp placed in an aluminum, paper or plastic housing. For convenience, an inspection hole is made in the body.
It consists of two bimetallic electrodes, which, bending from the passing current, close and open the electrical circuit. After that, the New Year's tree garland began to blink quite quickly.
This scheme is very simple and convenient, but has a significant disadvantage. When one light bulb burns out, the electrical circuit is broken and the entire garland goes out.
Parallel connection
Modern Chinese Christmas tree garlands are included in a parallel electrical circuit. By doing this, they extend the service life of the garland and delay repairs for a long time.
The whole point is that when the bulbs in a Christmas tree garland are connected in parallel, the voltage remains the same on each element of the circuit. Which gives a lot of advantages, the main thing is that if any light bulb in the circuit burns out, it does not break and the garland continues to work. As for the current strength, it is different for each element of the circuit.
This scheme is the most common in home electrical wiring, due to its reliability, convenience and simplicity.
The main malfunctions of New Year's garlands
Let's simulate the situation: you take out your Christmas tree decorations and New Year's garlands from the closet, start decorating the tree, turn it on, and nothing happens. Disappointment and despair on the faces of your children, faith in New Year's magic disappears, the holiday was not a success.
It is still possible to fix everything, even if there is a delay of fifteen minutes before the chiming clock, using your own strength and a simple tool.
The garland shows no signs of activity at all. We look at the electrical plug, its integrity is called a device. To do this, we disassemble the control unit of the Chinese garland, and look at the contacts that come from the electrical plug.
We place the switch in the diode measurement, press one probe to any contact of the plug, and apply the second to the wire contact on the control unit board. If the device makes a squeaking sound, then the wire is working, if not, then it is broken. We do the same with the second contact. Both turned out to be intact, we look for the fault further, if one is broken, we change this part of the wire along with the plug, and turn it on again. It burns normally, we are happy, no, we search further.
A small addition, a control unit for the blinking cycles of the Chinese garland, is located on the wire, immediately after the plug. This is the green box with the button, by pressing which you change the frequency of the New Year's blinking.
How to check a garland light bulb
If the garland is made with a series connection of light bulbs, then most likely one of the lamps has burned out. The electrical circuit is open, and current can only flow through a closed circuit.
To restore the functionality of the Chinese New Year toy, you simply need to replace the damaged element. But first you need to check the light bulb, which is under suspicion.
You can check by external inspection; the easiest way is to find an incandescent coil in a glass vacuum cylinder. When current passes through the spiral, it begins to glow in the spectrum visible to our eyes. If it burns out, it will be visible to the naked eye.
You can check it with a tester; to do this, switch the switch to resistance measurement mode. We connect the probes to the electrodes of the incandescent lamp, and look at the display of the digital tester. The working light bulb from the garland should have a resistance, and quite a large one; if it is missing, then we change it.
You can check the light bulb from the garland using an adjustable power supply, whoever has one, of course. We connect the light bulb to the terminals, set the voltage to 1.5 volts, the spiral should heat up a little. You can add a little voltage, although one and a half volts is enough.
If all the light bulbs and the power cord with the electrical plug ring, everything is fine, but for some reason the garland does not work? We are looking for a wire break in the garland itself.
It’s a little simpler here, we set the tester to diode testing mode, put one probe at the beginning of the wire on the board itself, push the second one to the wire inside the socket where the light bulb was. We heard a squeak, which means the wire is intact, put the probe on the next wire in the base, and continue the procedure until the end of the New Year's garland.
Garland control unit repair
It happens that the control unit itself for blinking garlands is to blame, a possible malfunction, a simple separation of the wire from the board, as a result of a strong jerk or cold, poor-quality soldering, or other problems.
To troubleshoot the problem, you need to disassemble the plastic box with the control unit itself. On the reverse side there are two screws for a “plus” screwdriver, figured, unscrew them and carefully remove the board.
On the board we see a circuit consisting of elements, electrolytic, two transistors, four diodes, one miniature button. On the board there is an open-frame microcircuit that looks like a black drop, and a pair of resistors.
The capacitor in the Chinese garland control unit has an electrolyte installed, which means it has polarity and must be observed. On the board that I have, it has a rating of 10 microfarads, at 25 volts. Transistors PCR 406, if suddenly during the operation of the New Year's garland, one of the transistors exploded, most likely, the second one will be completely identical. Diodes, all four are marked, IN 4007, a very common diode, there will be no problems with replacement.
As for the packageless microcircuit, its nominal value is written on the reverse side, B - 803, although in most cases it is known only to the manufacturer.
Troubleshooting Christmas garland
Let's start repairing the control unit and the Chinese New Year garland. We solder all the contact points on the board, it happens that cold soldering is not noticeable to the eye, so we carry out normal soldering, everywhere.
The next step is to check the semiconductors, these are diodes and transistors. Their checking is carried out by a tester; the diodes should be checked in one direction, and practically not pass a signal in the opposite direction.
The transistors need to be unsoldered; for a more accurate check, we check them with a tester. We replace damaged parts with new ones or with known good parts suitable for repair.
Capacitor, resistors and mini button, just check for integrity. When tested, they should not show a short circuit or a complete lack of resistance.
If you have followed all the recommendations for repairing an electric garland, and it does not work. You can exclude this block from the diagram and connect the wires in a straight line. You can also completely change all the wires. Of course, this is long and labor-intensive, but for beginner radio amateurs it will be excellent practice.
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The garland came in such a simple package with the name “Happy Diwali”:
What else is Diwali and what does Santa Claus have to do with it?
Although there is a proud MADE IN CHINA on the packaging, it is possible that the development could not have been done without Indian developers. Wikipedia tells us that Diwali is a major Indian and Hindu festival. Diwali is celebrated as the “Festival of Lights” and symbolizes the victory of good over evil and candles and lanterns are lit everywhere to mark this victory. The main theme of the festival decorations is glowing lanterns, lights, fireworks and lit candles.
The mode switching unit is a small, lightweight white plastic box with a single button. The block lists the available modes:
- Combination
- In Waves
- Sequential
- Slo-Glo
- Chasing/Flash
- Slow Fade
- Twinkle/Flash
- Steady On
Control block: 
An autopsy showed that the block inside is not empty: 
No strong otherworldly odors were noticed, just the usual faint smell of plastic (if you sniff specifically). There are also no smells during operation.
The garland has a Euro plug, very flexible wires in a translucent colorless braid. The inscription on the plug is 2.5A 250V (the store states the power is 6 W). The plug ends are not rounded, making it difficult to use in childproof outlets. 100 LEDs stated (did not count). The distance between the LEDs is approximately 8-10 cm. The approximately measured length of the garland turned out to be about 9.7 m (including the wire going to the block). The wires could perhaps have been made thicker, but no problems arose during operation.
The lighting is quite bright, the video may have a very frequent flickering effect, but this is mostly due to the rapid change of modes when shooting, and in general most of the modes use fairly smooth color changes in the effects.
Photo of the garland in working mode: 
This is how it works in real life:
It’s worth noting right away that LEDs in a pile don’t look as nice as if the strip were hung, for example, on a Christmas tree. She worked successfully last season for about a month, several hours a day (she’s also working now). Definitely worth the money.
