When the construction of a country house is completed and construction waste has been removed, it’s time to think about landscaping the country house. Places have been identified for a gazebo, flower beds, and possibly a swimming pool. Paths are marked. And then the question arises, how to cover all this business. You can, of course, use a lamppost and a common street lighting lamp. But at the same time, it is unlikely that in the dark you will get that unique atmosphere of mystery and comfort that can be created with the help of small, varied lamps scattered in different places on the site.
Installing such lamps throughout the site is not so difficult. But they need to be powered. But as? Dig trenches and run cables to them? Or, what’s worse, hang wires on poles? And install its own switch on each lamp? This is irrational. The problem can be solved much easier. Solar-powered lamps are installed on the site. Stores offer a huge selection of such lamps. From the simplest and cheapest, to the most complex and expensive, artistically executed, program-controlled, with a multi-colored glow.
But the cheapest ones are cheap because their quality leaves much to be desired, and after a year or two of service they can be easily thrown away. But high-quality lamps that would satisfy any discerning taste are expensive and not always affordable. That’s when ingenuity comes to the rescue, and craftsmen make solar-powered lanterns themselves, with their own hands. Such a lantern, made with love and conscientiously, will serve faithfully for many years. Making it is absolutely not difficult, as it may seem at first. Some difficulties may arise with choosing the design of the appearance of the lantern, but this will depend only on artistic taste. Well, and to some extent, from the set of components from which the electrical part of the flashlight will be assembled.
A set of components for a solar-powered lantern
Before you start purchasing parts, you need to decide how many lamps will be installed and in what places. What will be their power? Having decided on this, you can begin to select components for the lamps.
Naturally, for a solar-powered lantern, you first need to purchase solar modules. Helium converters of various modifications, quality and efficiency are available for sale. If we consider that the main purpose of these converters is only to charge the battery during daylight hours, then it is quite enough to purchase at retail a certain number of solar modules, from which, if necessary, you can assemble a sufficiently powerful battery.
For these purposes, a solar battery based on polycrystalline silicon 5.5 V, 90 mA, having dimensions 65x65x3 mm, is quite suitable. This battery is laminated with silicone, thanks to which the battery is completely protected from all kinds of mechanical influences and moisture. This also made it possible to reduce the weight of the battery to a minimum - only 15 grams. The battery is ideal for charging 3.6 V – 4.8 V batteries. The retail cost of the battery is 137 rubles.
Solar panels Solar Panel 65x65
The next component of the lamp is the battery. A lithium-ion battery with an output voltage of 3.6 V and a capacity of at least 3000 mAh is quite suitable for it.
From the relatively inexpensive batteries available on the market, you can choose a set consisting of four lithium-ion batteries model 18650. Each battery has an output voltage of 3.7 V with a capacity of 9800 mAh. The package also includes a charger, which may be quite useful, for example, for the initial charging of batteries. The batteries have the following dimensions: diameter – 17 mm, height – 65 mm. The price of the set (with charger) is 411 rubles.
18650 battery kit with charger
Next you need to select a luminous element. The most suitable for these purposes is LED. You can, of course, use LED lamps, but they will consume too much energy. Modern LEDs with increased brightness can satisfy any need, since they can be installed in the required quantity for each specific lamp.
For such flashlights, a five-millimeter super-bright white LED of type 3H5 (helmet) is quite suitable. It is usually used in outdoor advertising, in various electronic displays, and in road signs. So it is quite suitable for a flashlight. It can be operated at temperatures from -55°C to +50°C. The cost of one such LED is 10 rubles.
Ultra-bright white LED type 3H5 (helmet)
And finally, the heart of the lamp is the electronic control unit. His circuit contains four resistors, costing 1.5 rubles each, two KT503 type transistors, costing 9 rubles each, one Schottky diode 11DQ04, costing 24 rubles. This is all located on one board.
The solar battery, battery, and LED are connected separately. You can, of course, assemble all this on a piece of polystyrene foam, PCB, or cardboard. But no self-respecting master who collects something for himself would allow himself such sloppiness.
To install the block, it is not at all necessary to draw and etch the printed circuit board. The universal DIY PCB 42x25mm breadboard is perfect for these purposes. This board is designed specifically for mounting and configuring your own electronic circuits. It is made of high quality materials and has gold-plated contacts. The dimensions of this board are 45x35x2 mm. Weight 2.8 grams. The cost of packaging is 235 rubles. There are 4 such boards in a package.
Universal DIY PCB Development Board 42x25mm
When making an electronics unit for installation, it is best to use MGTF 0.2 grade wire. This is a stranded flexible copper wire in fluoroplastic insulation. Operates in the temperature range from -60°C to +220°C.
Operating voltages are up to 250 volts AC with a frequency of up to 5 kHz or up to 350 volts DC. A coil of such wire of 190 meters costs about 15 rubles.
Diagram of the electronic control unit for a solar flashlight
The operating principle of the electronic unit is extremely simple. The scheme works as follows. While the solar battery is illuminated by the sun, it produces a current that charges the battery through a Schottky diode. At the same time, current flows to the base of transistor T1 and opens it.
Since transistor T1 is open, the base of transistor T2 maintains a zero potential, and this transistor is closed. When darkness falls, the solar battery stops producing electricity, transistor T1 closes, and current flows to the base of transistor T2 through resistor R2, opening it. This creates a power supply circuit for the LED. At the same time, the Schottky diode prevents the battery from discharging to the solar panel.
Schematic diagram of the solar lantern control unit
The capacity and charge of the battery is sufficient to power several of these LEDs, which will create the desired luminous flux. This circuit allows you to connect up to three or four LEDs in parallel.
As for the appearance of the lantern, everything depends on the imagination of the master and his taste. You can give it any shape that will be most in harmony with the environment. These can be just lanterns for illuminating paths, they can be garlands for trees, bushes, they can be decorative lamps for gazebos, for lighting fountains. But they will all serve long and faithfully. Because they were made with their own hands.
Many summer residents dream of decorating their garden plot at night with portable solar-powered flashlights, but many simply cannot afford such luxury. There is a way out: by assembling lamps with your own hands from inexpensive radio components, you can easily organize a real scattering of lights in the garden.
Purchased lamps more often disappoint than delight. They shine dimly, work only for a few hours and hardly last longer than two years. When assembling a garden lamp with your own hands, you determine the necessary parameters yourself and can count on a guaranteed result.
The operating principle of such a lamp is very simple. During the daytime, the sun hits a photocell, which generates electricity and charges a small battery. When the solar panel voltage drops, a transistor switch cuts off the current from the solar panel to the battery and supplies power to one or more bright LEDs. When voltage appears at the photocell contacts, reverse switching occurs.
What parts are best to order and where?
The most difficult thing is to get hold of solar cells. Substandard items are suitable; the easiest way to buy them is on various online auctions, such as Aliexpress. Select a module with an output voltage of at least 5 volts; the power must correspond to the number of LEDs. It is very important that the module has conductor taps; otherwise, buy those that come complete with flat conductors and a flux pencil.
The most expensive element of the lamp is the nickel-metal hydride or lithium-ion battery. You need batteries with a voltage of 3.6 V, they look like three AA batteries covered in film. The capacity must also correspond to the total power of the LEDs multiplied by the number of hours of battery life + 30%. Can be purchased together with modules.
Light sources are LEDs. Based only on the characteristics, you most likely will not be able to choose the appropriate level of illumination, so you will have to choose experimentally. It is recommended to use bright white LEDs BL-L513. They are easy to find in electronic components stores, for example, at Chip and Dip they cost 10 rubles. Each LED requires a 33 ohm current limiting resistor.
Also, for each lamp you need a 2N4403 transistor, a 1N5391 or KD103A rectifier diode, as well as a resistor, the value of which is calculated using the formula R = U baht x 100/N x 0.02, Where N- the number of LEDs in the circuit, and U baht— battery operating voltage.
How much will the parts cost?
In cheap Chinese lamps costing about 500 rubles. Only one LED is used, which is clearly not enough. Moreover, the battery voltage is 1.5V, which is why the light is very dim.
| Elements | Price | Qty | total cost |
| Solar modules Eco-Source 52x19 mm | 675 rub. for 40 pcs. (for 4 lamps) | 1 set | RUB 675.00 |
| Battery SONY HR03 (1.2 V 4300 mAh) | 885 rub. for 12 pcs. (for 4 lamps) | 1 set | RUR 885.00 |
| LEDs BL-L513UWC | 10 rub./pcs. | 12 pcs. | RUR 120.00 |
| Resistor CF-100 (1 W 33 Ohm) | 1.8 rub./pcs. | 12 pcs. | 21.60 rub. |
| Transistor 2N4403 | 6 RUR/pcs. | 4 things. | RUB 24.00 |
| Diode 1N5391 | 2.5 RUR/pcs. | 4 things. | RUB 10.00 |
| Resistor CF-100 (1 W 3.6 kOhm) | 1.9 RUR/pcs. | 4 things. | 7.60 rub. |
| Total: | RUB 1,743.20 |
It turns out that to assemble one high-quality lamp you need approximately 435 rubles worth of components. But from these same parts, by purchasing the last 3 items, you can make 12 analogues of cheap Chinese lamps.
Soldering a simple circuit and assembling the parts
To assemble such a circuit, it is not necessary to have a textolite base and etch out the tracks. The cathodes (short leg) of all LEDs are assembled into one unit, and 33 Ohm resistors are soldered to the anodes (long leg). The tails of the resistors are also soldered together and soldered to the collector of the transistor. A 3.6 kOhm resistor is connected to the base of the transistor, and the cathode of the rectifying diode is connected to the emitter. The anode of the diode is connected to the base resistor, and the positive pole of the solar modules is supplied to the same unit. The negative from the modules and the battery is connected by wires to the combined cathodes of the LEDs. The positive terminal of the battery is connected to the emitter of the transistor.
Electrical diagram of the lamp
Individual solar modules have a voltage of 0.5 V, and to charge batteries you need 4.5-5 V. Therefore, individual modules must be combined into chains. First, solder the conductors to the modules if there are none. To do this, cut the flat conductor into strips slightly longer than the width of the module. If the module is 19 mm, cut 25 mm.
The positive contact of the module is located on the back side, and the negative contact is that same central strip on the front part. You need to run flux along this strip - this is a colorless marker from the kit. Then a piece of conductor is laid over the contact. All that remains is to slowly move the soldering iron from above: a thin layer of tin is already on the conductor. The remaining tail is soldered to the contact on the back of the next module and so on along the chain until 10 modules are assembled in two rows.
Between the rows you need to make a jumper from a flat conductor, and solder thin copper wires to the remaining two ends. Be careful when handling the modules, they are very fragile. It is also not advisable to overheat them, so do not keep the soldering iron in one place for too long.
Design and assembly of the lamp
The lamp requires a housing, preferably waterproof. It is very convenient to use an empty canning jar with a screw-on lid.
Example of parts layout
To assemble such a lamp, you need a piece of plywood to glue two rows of modules onto it. The proposed photocells have a size of 52x19 mm; folding them in two rows will result in a rectangle with dimensions of approximately 110x110. You can glue the modules using double-sided tape for mirrors, but do not press down too hard.
Before gluing the modules, cut a hole in the center of the board for the lid of the jar and secure it inside with a couple of drops of hot glue. You need to pierce two holes in the cover to enter wiring from the modules; do not forget to restore the seal later.
To conveniently place electronics inside, glue a small foam washer to the inside of the lid. If you don’t bite the legs when soldering the circuit, you can stick the elements into the foam and fix them that way. And if you make rectangular cuts in the foam, you can easily insert batteries into them. For contact, use a pair of flattened balls of aluminum foil with wires soldered to them.
Before closing the lid, warm the inside of the jar well with a hairdryer. This way the parts will oxidize less, and condensation will not appear on the walls of the jar.
Some operating secrets
Lamps do not tolerate cold very well, so it is advisable to bring them into a warm room for the winter. The batteries need to be completely discharged by covering the solar panel with something opaque. Wrap the batteries separately in paper to help them last longer. Also consider covering the modules with a clear protective coating or using film solar cells. In general, such lamps last for 6-7 years of active use.
Good afternoon, dear Radio Amateurs!
For almost a month now, the section “ From readers“. To be honest, I was already beginning to think that this idea of mine was a failure - there was no response from readers to the proposal. And this morning, while looking through the site’s mail, I was pleasantly surprised to find a letter inviting me to publish an article. But I was even more surprised, and one might even say amazed, when I saw who the author of the article was.
So, dear Radio Amateurs, today, in the “From Readers” section, it is with great pleasure and respect that I present to you an article by the author of many interesting and informative publications and books - Yuri Vsevolodovich Revich:
Refinement of solar-powered garden lamps
A few years ago, in large supermarkets (Auchane, Leroy-Merlen) surprisingly cheap (priced less than a hundred rubles) garden lights with LEDs and a built-in solar battery for recharging during the day appeared. After some time, they appeared in almost all retail outlets selling electrical items or gardening supplies. The lamp looks something like this:
A good initiative, however, turned out to be somewhat spoiled by the fact that the brightness of the small LED is not enough to seriously illuminate something, so the lamp rather performs decorative functions and quickly gets boring with its deathly white glow. In addition, in real light conditions, the power of the solar battery is not enough to recharge the battery normally - the lamp burns for two to three hours after sunset and then “dies”.
There is, however, a simple way to correct both shortcomings at once, and turn the product from a disposable toy into a beautiful and functional element of the garden landscape. Of course, it is impossible to turn it into a full-fledged lighting device, but it is easy to significantly improve the decorative qualities of the lamp if you replace the LEDs with colored ones. The latter are available in many different colors (not only white-red-yellow-green-blue, but also different shades - for example, green is not only just green, but also yellow-green and bluish-green, and yellow - and thick yellow and lemon). All of them, both regular and high-brightness, of any size and geometry, can work in these lamps without modification (with the exception of special powerful lighting and still blinking LEDs, which themselves constitute a complete circuit). When replacing, just pay attention to the polarity of the LED, and practically nothing else is required. The lamps work quietly even in winter with slight frosts, but in severe cold weather it is better to put them indoors by removing the battery.
However, the second problem may even be aggravated: a small voltage drop across a color LED will make it burn very brightly, but even in the summer only for half an hour or an hour. This is especially problematic in the fall and winter, when daylight hours are shortened and cloudy weather means that the battery charge accumulated during the day only lasts for a couple of minutes.
This drawback is also easy to correct if you connect a resistor with a value of several tens of ohms in series with the LED. Use a sharp cutter to break the track on the board leading from the microcircuit to the LED and install a resistor in its place (the figure below shows a modification of the lamp board from Leroy-Merlin; in other cases the board may look different):
The resistor should be selected in such a way that the current through it is 4-6 mA - this is enough for normal brightness, and when the standard 600 mAh Ni-Cd battery is fully charged, the lamp will then work for several days (in practice, a full charge, of course not achieved).
At the output of the lamp microcircuit, there is a rough current source with an open-circuit voltage of about 2.5 V - that is, approximately equal to twice the battery voltage. When a load is connected, this voltage drops, and the resistor must be selected so that the voltage drop across it corresponds to the selected current. For example, for a red LED the rating can be 75-91 Ohm (voltage drop across the resistor 0.4-0.5 V), for a green high-brightness LED - from 47 to 62 Ohm (voltage drop 0.2-0.3 V) and etc.
By the way, usually a standard Ni-Cd battery lasts no more than a year, then it breaks down. Experience has shown that a regular AA Ni-MH battery can be installed in the lamp, and the cheaper (that is, the lower its capacity), the better - the existing solar battery is still not enough to fully charge a battery with a capacity of 2000-3000 mAh , and in any case it will work only at a small part of its capabilities.
For those who (due to their youth) are unfamiliar with Yu.V. Revici:
Engineer and journalist with many years of experience. The main range of interests is information technology, its impact on modern society, technological innovation, the history of computers and technological innovation. Regularly published in magazines, newspapers and online publications. Author of 6 popular books, including “Entertaining electronics”, “Self-instruction manual for working on a PC for everyone”, “Practical programming of Atmel AVR microcontrollers in assembly language”, etc.
Almost everyone has solar lanterns for their garden. And they break often. And what? Buy new ones? Not at all!
I have been using solar-powered garden lanterns at my dacha for more than 5 years and I can confidently say that even the cheapest and most unreliable of them are very easy to bring back to life. The electrical circuit of a garden lantern is so simple that there seems to be nothing to break... if not for the poor build quality.
The most common fault is poor contact between the battery and the power container. I will not recommend the traditional method of hitting the flashlight, since the effect, if any, will be short-lived. The correct solution is to disassemble and clean the contacts of the power container and the battery poles.
The device itself is very simple. The dark piece of glass is a solar battery. The current it generates during daylight hours charges the battery that powers the LED during the dark hours. Turning on the lamp is controlled by a photocell and a microprocessor (in the simplest flashlights there are transistors).
LEDs are used to emit light; unlike incandescent lamps, they have a significantly lower current consumption and, therefore, can shine longer.
A photocell is a semiconductor device that converts light energy into electrical energy. Usually located in the same plane with the solar battery or they are made in one block.
The microprocessor can set different modes of operation of the lamps - for example, garlands of iridescent colors or flickering candles.
Next, I will list the most common breakdowns of solar-powered flashlights and how to fix them.
Poor contact between battery and power container
If the flashlight has not been used before, it is likely that the problem is the starter strip (the liner between the battery and the container) that has not been removed.
If the flashlight worked for some time, and then began to “mope”, it is worth cleaning the oxidized contacts of the container (say, with sandpaper).
It is possible that the battery is slightly offset in relation to the contacts of the container (and this can happen if the manufacturer saved money and used a non-standard container). In this case, you need to carefully pull out the negative spring, after first removing the battery. Additionally, I recommend securing the battery in the container using double-sided tape.
The battery is completely discharged
Either the battery has failed, or it was not charging, for example, because the flashlight is installed in the shade. In this case, you can check the voltage on the battery using a tester (the voltage should be between 1.1 and 1.4 V) and try to recharge the battery by placing a flashlight in a sunny place.
The solar lantern does not light up in the dark or lights up in both light and darkness
Perhaps the problem lies in the solder connections, and you will have to open the flashlight housing.
First of all, I check whether all the wires are in place, whether there are any breaks or tears, and also how well the soldering joints of the wires are made. If a green, blue or white coating in the form of salt crystals is visible in the soldering areas, it means that the soldering was performed with an active flux, and the soldering areas were not washed. This technology is used to speed up the assembly process, but the quality suffers greatly. In outdoor conditions, accelerated corrosion occurs at solder joints, which worsens contact or even dissolves soldering.
I remove multi-colored “frost” on the printed circuit board inside the flashlight with a cotton pad soaked in acetone. I just wipe the board until the cotton wool is clean. Then I wash the board under running hot tap water, rubbing it with a hard brush to better rinse off any remaining flux, then dry it thoroughly. After this, as a rule, the flashlight starts working as usual. For example, a lamp that has passed a similar test is no longer
How many years has it been working successfully? True, I additionally treated all the body joints with a colorless sealant, since after disassembly and reassembly the seams might not fit together tightly.
The solar-powered flashlight stood in the sun all day, and with the onset of dusk it went out very quickly
Most likely, the battery is outdated; usually its service life is no more than 5 years. An old battery quickly loses its capacity, and a flashlight with such a battery will not shine for a long time.
Or maybe the protective cap over the solar battery has become cloudy (from time to time). This happens especially often in budget models, the cap of which is made of plexiglass. More expensive flashlights use regular glass, which lasts longer. If the plexiglass gets dirty, it can be washed using glass detergent. Just keep in mind that abrasive powders and pastes are contraindicated for plexiglass!
If the glass of the solar lantern body breaks
In this case, you can try to solve the problem by choosing a suitable replacement from scrap materials. So, I replaced the broken flashlight body with a piece of a plastic bottle. The color rendering may have changed a little, but the flashlight continues to serve.
©A.BELK Moscow region.
Continuation, first part on the Belka House website.
Exactly a year has passed since the first article, it’s time to take stock. Finally I managed to take some photos of garden lamps in the dark, I posted them below in the text. It is also pleasant to note that other garden areas have become interested in night electrification. And what? Convenient and beautiful!
The seven original light green flashlights worked great last year, but after winter storage, two of the batteries failed. Instead of 1.1 - 1.4 volts, they showed 0.3, no matter what charger they were in. But everything went into winter storage fully charged and stored at a low temperature. Conclusion: the second place in terms of product failures is occupied by battery cells. Well, the first thing, I will remind you, from the first article, is the poor quality of the unifying installation of the product. If the manufacturer supplied the products with reliable batteries, the flashlight would be uncompetitive due to its high price.
Identify a faulty battery as easy as pie.
Every household must have a tester, preferably one with a digital display. With this device we measure the voltage of the battery. We set the limit = 2 V, which means constant voltage, it also corresponds to the symbol DC. If after being in the charger for at least an hour, the reading on the element has not changed upward, then its place is in the container for technical waste. The battery can be tested using a garden torch that is known to be in good working order. Moreover, you don’t need to wait for the sun, it’s enough to use a lighting lamp, preferably an energy-saving one, with a power of 11-14 Watts. Energy-saving light bulbs do not heat up much during the measurement process, so they will not damage the lantern.
In the same way, having a known good battery, they check the performance of the garden flashlight itself, namely the moment of charging the battery from the solar battery. For this purpose, it is advisable to use a slightly discharged battery with a voltage of about 1.2 volts. If, when the lighting lamp is turned on, the reading of the device measuring voltage begins to increase, and the digital device shows a change in the fourth digit in the positive direction within a few minutes, then the solar battery is working. The flashlight is fully operational when it lights up in the dark and goes out in the light.
Poor contact in power container- the main reason for the flashlight malfunction. Using active flux to solder wires leads to the formation of salts on the contacts of the power container. A similar blue coating may be present on the circuit board of the flashlight's electronic device. This product needs repair.
In addition, they gave me new flashlights in the form of glowing frogs. Time to build a small pond for bathing your baby or future babies.
True, a high snowdrift dismantled it into two parts, leaving it lying in a spring puddle. I picked it up, cleaned it of dirt, folded it, and put it in place. It seems like nothing bad happened. Yes, you can see it in the photo.
One of these flashlights failed immediately, last year. The design, as it turned out, was non-demountable. There was no way to even check the voltage on the battery. But that’s why there is a sharp knife, with which we get to the battery. In these lamps, the power container is a switch; by pressing a lever, it moves relative to the battery. The battery itself in the container shifted and did not contact. But now the hole was not made in vain, and the switch is no longer needed. For storage, you just need to remove the element from the container. 
The blinking garland has the most failures, and it all comes down to two contacts. I can’t imagine how to reliably connect them to a solar battery.
While disassembling the garland once again, the tester was well at hand, and discovered that one of the batteries was faulty, and there were three of them! During the charging process, they heat up, and the black housing of the electronic solar battery unit in which they are located is additionally heated in the sun. High temperatures are undesirable for batteries; the probability of failure of such a product increases three times, since there are as many as three batteries.
Added October 5, 2012.
It's autumn again, it's getting dark quickly. Lanterns are a must at this time of year. I was visiting my son and discovered that 2 lights were not shining. I didn’t have a tester with me, so I decided to take them with me and at home, without rushing to check them. Here they are in the photo. Everything is very simple, the battery showed 0 volts. I installed new batteries and everything worked. I already repaired my first flashlight last year. It had an interesting malfunction. If you hang it up, it doesn’t light up, if you put it down, it lights up. It is necessary to remove the upper cap and on the lower part of the flashlight body bend upward the 2 contacts to which the spark plug wires are connected. The design itself is original, the candle flickers as if the flame is burning for real. The second lantern is made to last, you can feel it being made domestically, its body doesn’t show signs of aging. You just need to change the battery on time.
It’s late autumn, we go to the dacha less and less often. There are fewer and fewer sunny days. The battery does not fully charge during the day. At dusk, the flashlight will light up for 15 minutes and go out. The battery is not operating very well, it’s time to take care of it and the flashlight itself. After all, a new battery costs more than the flashlight itself. Usually, in late fall, I disassemble my lamps, wipe off any dirt, and put them in shipping boxes until spring. I put the batteries themselves on charge. It’s good if you have a normal charger, in the sense that it can digest your very discharged cell, and not blink in fear, thinking that they slipped something wrong. Where did I charge my batteries: in the battery compartment of a pocket receiver, which was designed to be powered by batteries with subsequent charging, and in the container of a radio mouse powered by the same batteries.
