New generation lighting devices are radically different from older models. They are economical, demonstrate high power and require virtually no maintenance.
The steady demand for high-quality light sources has caused the appearance on the market of a large number of products from Southeast Asian countries that are neither reliable nor durable.
A DIY LED spotlight will allow you to get a fairly high-quality product. Let's look at how to make a cheap and fully functional spotlight from improvised materials.
The design of the LED floodlight is simple. The main elements of the device are:
- Driver.
- Light-emitting diode.
A driver is a block or power source that receives standard 220 V and converts it into the power needed to operate LED flashlight. A feature of drivers that distinguishes it from adapters is the emphasis not on voltage or power, but on stable current (for adapters, the main parameter is voltage).
Attention! When purchasing a driver, you need to pay attention to the main indicator. If the value is indicated in volts (for example, 24 VDC), then this is an adapter.
LED in in this case is not a separate element, but an assembly of several units with the same characteristics. They are manufactured using a special technology that allows one to obtain identical crystals. A set of crystals connected in series and parallel makes up an LED matrix or LED-cheap. Distinctive feature matrix is a large release of heat, which destroys the crystals and requires cooling or removal using radiators.
In addition to the main components, the spotlight consists of the following elements:
- Frame.
- Reflector.
- Lens.
The purpose of the body is clear without explanation. The focusing lens creates a compact and directed light flux, more concentrated and dense. The role of the reflector is somewhat different than in conventional spotlights. The original LED optics produce a beam of light with an opening angle of 120°. Therefore, the function of the reflector is not so much to reflect multidirectional rays as to compress the flow.
Required materials and parts
You can make a homemade LED spotlight from parts that you have on hand or purchased at a specialized store. It is necessary to think through the design so that all elements match each other as much as possible. It is not necessary to purchase the necessary materials; you can use an old lamp, take LEDs from a broken street lamp, etc. Let's look at what elements are needed to assemble a powerful LED spotlight.
Lamps
The easiest option is to purchase a ready-made LED lamp with a standard base and connect it to the network. But such a homemade product can hardly be called a spotlight. The best option- matrix based on SMD 5050 LEDs, inexpensive and high-quality, providing a bright, powerful beam of light. They are mounted on a thin fiberglass laminate mounted on a thick aluminum plate, which serves as a heat sink. You can use ready-made radiators with big amount plates, the efficiency of which is much higher, but their dimensions do not always allow them to be placed in the limited space of the spotlight housing.
Read also Choosing an infrared (IR) LED floodlight for video surveillance
Housing material
The body can be any metal or plastic box of appropriate shape and size. The best option is to use a ready-made housing from a halogen spotlight. It is sealed, designed for outdoor use, and is the right size. For people with the skills and capabilities, it will not be difficult to make the case themselves from sheet aluminum. This option will allow you to place a high-quality radiator and ensure the installation of the most effective reflector with an optimal opening angle. You should also consider the installation of switches and the method of attaching the housing - make a socket for the bracket or a mounting strip attached to the outside.
Power supply
Purchasing a ready-made driver will help you make a spotlight with your own hands much faster, but for people who are trained and have certain skills, it is not difficult to make a power source yourself. The main task is to ensure stable current and voltage.
Important! If you have doubts about your abilities, it is better to refuse to make a driver yourself and purchase a ready-made one. Errors in calculation or assembly can lead to fire.
Circuit and printed circuit board of a simple LED spotlight
Exists a large number of power supply circuits of varying degrees of complexity. The easiest (and most reliable) way is to use the classic version of the circuit with a quenching capacitor:
This option is a transformerless type of power source, allowing you to get a very compact device assembled from inexpensive and accessible parts that does not require complex setup. The input non-polar capacitor with a capacity of 1 μF is paralleled with a 1 mOhm resistor, which can be replaced with any other sample with a capacity from 240 to 1 mOhm and a power of 0.25 W. They connect on one shoulder diode bridge, which is assembled on 4 1N4007 diodes. The rectified voltage is further smoothed by a 10 µF 400 V polar capacitor. The LEDs are divided into 2 groups connected in parallel. Each group has 50 units connected in series. Each branch carries a current of 19 mA, which corresponds to the nominal value.
The printed circuit board does not require high precision and can be produced on a laser printer.
To effectively remove thermal energy, the reverse side is left untinned. The location of the mounting holes is selected to ensure the tightest possible contact with the heat sink plate or radiator.
Spotlight assembly procedure
Let's look at how to assemble an LED spotlight with your own hands.
- Assembly begins by soldering the LEDs onto the circuit board. To do this, use a low-power soldering iron or station. After completing the work, it is necessary to check each LED individually and the entire matrix for functionality.
- Then the driver is assembled. Usually they use a mounted method (without a mounting plate), since there are few parts. Their location must be carefully considered so that they fit freely in the compartment. Make sure to leave enough space for the power cord.
- To avoid short circuits, the leads of the parts should be insulated with cambric or heat-shrinkable tubing. The assembled power supply is checked for functionality, first separately using a multimeter, then with a load (a test connection of the LEDs is performed). Detected deficiencies are eliminated.
- After a successful test switch-on, the final assembly of the spotlight begins. The matrix with LEDs is tightly attached to the radiator. If you don’t have a ready-made one, you can use an aluminum corner bent from a thick (about 5 mm) plate. One shelf of the corner is screwed to the body of the spotlight, the matrix is attached to the second. It is necessary to apply thermal paste between it and the plate for better removal of thermal energy.
- Then install the reflector. If you don’t have a ready-made one, you can get by with installing aluminum foil, a structure made of mirror plastic or other materials with high reflective abilities. The best option is the use of rigid sheet materials that make it possible to produce a durable structure with a given configuration.
- The assembly is completed by installing protective glass or focusing lens. Glass is most often used, since the lens is much more difficult to find and its price is quite high. If you plan to use the spotlight for street lighting, all joints around the perimeter should be sealed from water with sealant.
You can make an excellent LED spotlight with your own hands, spending only 257 rubles on the filling! Even if you are not familiar with electronics and have never soldered a single printed circuit board with radio components in your life!
This spotlight can be successfully used for landscape lighting of a summer cottage, for accent lighting of a house, for illuminating an object at a distance of 20 - 30 m when using external surveillance cameras... And much more!
But, most importantly, your spotlight will consume only 6 W of electrical power with a stable luminous flux when powered in the voltage range of 85 - 256 Volts!
Let's get down to business. We really liked the Kreonix STD-JCDR-6W-GU10-COB/WW LED lamp, developed by Russian engineers and manufactured by Kreonix.
We tested it and were very pleased with the high brightness of the LED, temperature conditions and the operation of the driver (current stabilizer) at different supply voltages. After which, we recommended this lamp for sale to our partners.
The lamp turned out to be universal. In addition to using the new LED lamp Kreonix STD-JCDR-6W-GU10-COB/WW in turned ceiling lamps, in lighting decorative niches and in accent lighting of interiors, in our opinion, the lamp is also suitable for outdoor use, provided it is adequately protected from external influences .
From this lamp we will make an LED spotlight with our own hands.
Unlike ready-made LED spotlights, the Kreonix STD-JCDR-6W-GU10-COB/WW lamp does not shine 180 degrees, scattering precious light to the sides and into the sky, but with a beam with an opening angle of 30 degrees. This is what you need for a spotlight! After all, with the same LED power, you can illuminate objects located several times further away!
As a housing, we used the housing from an old 150 W floodlight. But you can buy a new one. It's very cheap. The halogen spotlight had to be disassembled and the unnecessary ceramic socket removed.
We glued a new cartridge for the GU10 base to the center of the case using silicone sealant. We used glue so as not to bother with making the mechanical fastening of the cartridge. After all, we didn’t have any special machines or tools at hand.
In the center of the foil reflector that stood in the spotlight, we cut out a hole with nail scissors into which the base of the Kreonix STD-JCDR-6W-GU10-COB/WW LED lamp should go.
We started assembling the LED spotlight without waiting for the silicone sealant to set. This was done not only because of our haste, but also to control the direction of the light flux from the lamp. In addition, the Kreonix STD-JCDR-6W-GU10-COB/WW LED lamp with a socket fits precisely in the housing and, when the glass is closed, is lightly pressed by it.
This The best way fixing the lamp with the socket while the adhesive-sealant polymerizes!
We routed the wires from the socket into the mounting box on the body of the spotlight. But the place where the glass adjoins the removable frame had to be additionally sealed with silicone (transparent) sealant. Just in case, we sealed other leaks and gaps.
After assembly, we turned on the lamp and rejoiced - we did it! We made an LED spotlight with very remarkable characteristics with our own hands! By the way, there is enough space in the case for two LED bulbs, if you install them side by side. But we don’t need such brightness now.
Immediately after assembly, if the weather was not rainy, we mounted our new LED floodlight on a pole, connected it to the photo relay line and eagerly waited for nightfall to compare the homemade light with the FL-10 10 W factory LED floodlights available on site...
...We were not disappointed! The narrow beam of the Kreonix STD-JCDR-6W-GU10-COB/WW lamp pierced the darkness about 5 times further than the larger FL-10, illuminating what we needed!
And further. You can check the quality of the case sealing after rain: there should be no condensation on the inside of the glass.
Until LED products fully enter our lives and production is fully on track, the price of LED lighting equipment will continue to bite. But why wait or, even worse, overpay, if you can assemble a spotlight of the required power with your own hands according to our instructions.
Electrical features of working with LEDs
If you intend to use LED technology, it would not hurt you to learn about some of the intricacies of working with it, which can partly be called disadvantages. On the one hand, LEDs are compact, economical and durable light sources, but on the other?
Solid-state semiconductor elements are critically sensitive to high temperatures in the core. A phenomenon called degradation is the loss of dopants from a semiconductor, resulting in a decrease in luminous flux or eventual failure.
a) design of a conventional LED: 1 - anode; 2 - cathode; 3 - conductor; 4 - crystal; 5 - plastic lens
b) design of a high-power LED: 1 - housing; 2 - conductor; 3 - heat sink; 4 - crystal; 5 - lens; 6 - cathode
At temperatures above 60 °C, the LED degrades very quickly and the 50 thousand hours declared by the manufacturer ultimately turns into 3-5 thousand. And the more powerful a single LED, the higher the likelihood of it quickly aging due to overheating. Therefore, when developing lighting devices, the main focus is on a high-quality heat removal system, as well as dividing the emitter into several points and their correct arrangement.
Another feature of LEDs is that they can only pass a limited number of electrons per unit time. The network supplying the LED must be current stabilized, otherwise severe overheating and associated negative consequences. The current in the power circuit is regulated by the applied voltage and is limited by a resistor on each of the LEDs. When developing a connection circuit, you need careful calculation: set the voltage too high and the LEDs will quickly fail, but set it too low and they will only light at half power.
The simplest spotlights have only one light-emitting element, but in high-power devices it is recommended to distribute the load for more efficient heat removal. In such cases, the connection can be serial, parallel or mixed. The first is not entirely safe: if one of the LEDs burns out, it can either break the circuit or bypass it. With a parallel (and especially mixed) connection, there is a high risk that after one consumer is disconnected from the circuit, the current in the supply network will increase to unacceptable values.
Point sources and matrices: selection, procurement
There are three types of LEDs that are wise to use in making floodlights. Please note that when assembling a lighting device from several LEDs, they must be identical both in type and in current-voltage characteristics. It is also recommended to purchase up to a dozen spare diodes as a repair kit and in case of damage during installation.
LEDs in the form of a plastic capsule with pin terminals are suitable for the manufacture of small spotlights and flashlights. This is the cheapest type of product, and the final product will ultimately be relatively easy to repair.
The second type is ultra-bright white LEDs on a metal substrate. They should be used in high-power lighting devices; it is quite easy to remove heat from them.
Another type of LED is LED matrices high power. It is not recommended to independently manufacture spotlights with a matrix power of 20 W or higher: simple measures will not be able to effectively remove heat.
Housing and reflector parts
There are a number of solutions for the body of a homemade spotlight. If a high degree of dust and moisture protection is required for a street lamp, then a car headlight is suitable. The rim of the lamp base will need to be cut out and secured over the panel with the LED matrix. The disadvantage of the method is the limited power of the spotlight, given that only one matrix will fit in it.
If you place several LEDs or matrices on one printed circuit board or mounting panel, the housing can be made of sheet metal or sheet steel. On the workpiece, mark the development of a truncated pyramid: a square in the center and identical isosceles trapezoids on the sides. Don't forget to leave a "tongue" on one of the sides of each trapezoid to join the petals together. Also, in the smaller base of the trapezoid, you should leave a rectangular strip of about 15-20 mm, and in the center of the square, cut another one with a side 20-25 mm smaller.
When the pattern is ready, sand the edges, bend the body and rivet the seams. Prime the inner surface, cover it with white non-gloss spray paint and leave to dry for 2-3 days. From the front side of the case, place a square piece of glass of suitable dimensions diagonally and lean it against the curved shelves from the inside. Apply a generous amount of white silicone along the contour of the glass and coat the seams of the case with it.
Fasten the mounting panel or board using eight 4 mm bolts, having previously drilled holes along the edges of each shelf on the narrow side of the case. To ensure the plate fits tightly, use a PVC foam door seal. Tightening the bolts won't be easy; their heads are inaccessible, so use a pair of locked nuts on the end.
Installation of radio elements
If you chose LEDs with pin terminals, you will need a PCB plate to mount them. Think over the layout and draw current-carrying paths with a permanent marker. The anodes of all LEDs (long tails) can be assembled onto one ground bus. The cathodes are also collected at one point, but a current-limiting resistor should be connected in series to the power circuit of each LED.
Its calculation is simple: subtract the LED voltage from the supply voltage and divide by the maximum permissible current. To be on the safe side in case of source voltage fluctuations, the permissible LED current can be deliberately lowered to 90-95% of the nameplate value.
An example of an LED matrix circuit of diodes with an operating voltage of 3 volts and an operating current of 20 mA
The approximate supply voltage for one LED is 4 V. If the source produces more, it is advisable to turn on the diodes in a mixed circuit, where garlands are connected in parallel, each of which has one LED for every 4-5 V of voltage. The permissible current for such a series assembly is determined as the sum permissible currents each, and the forward voltage remains the same, provided that each LED has the same parameter.
Having placed the elements and drawn the paths, etch the PCB plate in a solution of citric acid (30-50 g), 3% hydrogen peroxide (100 ml) and table salt (2 teaspoons), periodically checking the degree of dissolution of unprotected areas. Drill holes for the pin leads with a 1.5-2 mm drill, drill eight holes to attach the board to the case, and then carefully tin the current-carrying parts with solder and rosin.
You can also use circuit board for LED matrix
If you assemble diodes or matrices on a cooling substrate, they are mounted using a hinged method. An aluminum comb-type radiator should be selected as the mounting panel. Each LED is attached using two or three holes, mark them all at once and drill from the back of the radiator with a 2.5 mm drill.
For fastening, use short 3.5x11 mm screws for metal profiles, but without a drill at the end. Before fixing the diode, apply a small amount of KPT-8 thermal paste to the substrate.
The cathode (-) and anode (+) of LEDs with a substrate are marked, the connection diagram and calculation of protective resistors are the same for all types. The elements should be connected to each other using a segment telephone wire. To avoid unnecessary work, the anodes can be immediately soldered with short jumpers to the body of the aluminum radiator.
Power supply question
After assembling the LEDs, you will be left with two terminals, which would be nice to apply voltage to, but where will you get it from? Household power supplies are of little use here; to power the LEDs you need an LED driver that produces a pulsating D.C. stable value.
For most products, a driver for interior lighting systems or for LED strips is suitable. It is better to purchase a power source in advance in order to use it to calculate the number and connection diagram of diodes according to the output voltage and total stabilization current.
For small crafts, you can use general-purpose power supplies with an output pulsating current of 0.5-1.5 A and a voltage 3-5 V higher than the direct voltage of the diodes. You can stabilize the power supply using the LM317 chip; for more powerful spotlights, use LM350 and LM338, respectively, increasing the power of the source.
The current limitation of the microcircuit can be adjusted by changing the resistance of the resistor. Its rating is defined as 1.25/I, where I is the current of the LED or assembly.
Outdated halogen floodlights have recently been widely replaced by LED lighting systems, which have higher efficiency, but the cost of such devices is much higher.
Craftsmen know how to assemble an LED spotlight with their own hands. To do this, you will have to buy the necessary parts, prepare tools and master simple skills.
Design features of the spotlight
Diode spotlights or LED devices are very economical in terms of energy consumption, require minimal maintenance, and their luminous elements operate for up to 50–90 thousand hours. The devices are suitable for outdoor use and do not deteriorate due to weather conditions, dirt, or dust. The quality of the emitted light is very high.
Is it possible to make a LED spotlight with your own hands? The design of such equipment is quite simple, so you can try to assemble it at home. Serious damage to a homemade spotlight usually does not occur, and anything that breaks can be repaired yourself.
The device will consist of the following parts:
- frame;
- fixing brackets;
- LED matrix;
- driver.
The matrix of the device consists of diodes attached to the board and protected from damage by special polymers.
Electrical specifics of the spotlight
Before starting assembly, it is necessary to clarify the electronics features of the LED-based floodlight. This will help to perform the work correctly and eliminate the impact of high temperatures on the active zone of the device. The fact is that solid-state semiconductors are highly sensitive to such changes, which causes their degradation and loss of dopants. Ultimately, a critical increase in temperature (from +60 degrees) causes a decrease in lighting intensity or complete breakdown.
Design simple LED provides for the following components:
- anode;
- cathode;
- lens and crystal;
- conductor.
A high-power LED includes a conductor, a heat sink, a crystal, a lens, and a cathode. It must be remembered that the power of the diode increases the risk of premature wear due to overheating. When creating a homemade product, it is important to ensure good system heat removal, correctly divide the emitter into several parts and install them correctly (series or parallel). In simple spotlights you can make only 1 emitting element.
It is equally important to stabilize the network in terms of current, otherwise overheating cannot be avoided. The current must be regulated by the applied voltage and limited by resistors on the diodes. When creating a circuit for an LED device, a strict calculation is made: if the voltage is exceeded, the LEDs will soon deteriorate, and if the voltage is too low, they will shine dimly.
Required materials and parts
To assemble a high-quality device, you need to buy all the necessary components in advance. Some can be found in the garage of car enthusiasts, others can be obtained from friends.
- LED matrix with driver. These are found on old lamp posts that are already out of order - their power will be quite enough, but the burnt out lamps will have to be replaced. It's even better to buy new element in a specialized electronics store.
- Frame. It is prepared with your own hands from various available materials - metal, plywood. You can take an old halogen flashlight or buy a new one.
- Connecting wires. Will be required to connect the finished device to the power supply.
- Foil. Needed to create a reflector. You can buy it at the grocery store, as long as the density is high.
- Reliable adhesive and sealant or 2 in 1 product.
- Cooling radiator. It will be needed to make a powerful spotlight - 100 watts or more.
To work you will need the following tools:
- Bulgarian;
- welding machine;
- drill with drill bit;
- soldering iron with solder.
Sources of light
LEDs are the main element lighting fixture, without them the main function of the device will not be performed. Their quality should be given the closest attention when purchasing. All LEDs within one device must be strictly identical in type and technical parameters (volt-ampere characteristics).
LED type
It is recommended to immediately purchase a sufficient number of spare diodes (up to 10), which will replace products damaged during installation. Unsuccessful installation is not uncommon, and buying with a reserve will save you from inconvenience.
There are three main types of LEDs:
- In the form of a plastic capsule with pin terminals. Suitable for creating low-power spotlights and lanterns, they are cheap. The light intensity from such diodes is low. Professionals have special instruments to determine the power of LEDs based on the size of the crystals themselves, otherwise you will have to trust the seller. Working with such LEDs is easy and repairing them is a piece of cake.
- Ultra-bright white LEDs on a metal substrate. They are used to create high-power lighting equipment; the heat removal system is effective and simple. The cost of such products is low.
- LED LED matrices. These are high-power LEDs, which are recommended only for professionals to work with. In the usual way It will not be possible to remove heat from them, therefore, the spotlight will quickly become unusable.
Housing material
Housings for spotlights can be purchased in an online store or in a specialized department of radio engineering and electronics. Their cost is quite low. You can “shake out” an old halogen lamp using its body as a basis. Both options are good because you don't have to invent a reflector that already exists inside. The price of a simple halogen lamp will be 150 – 200 rubles, and replacing the filling with LED will allow you to get powerful lighting equipment.
You can make the case yourself, but its aesthetic properties will be lower. To provide high degree For protection from dust and moisture, you should take an old car headlight. Aluminum radiators are used for excellent heat dissipation - they make high-quality cases.
To place a couple or more LEDs and matrices on one board, it is better to make a housing made of tin or thin sheet steel. After bending the box, the edges are polished and the seams are connected with rivets. The product is primed on top and metal enamel is applied. You can continue to work with the workpiece only after it has completely dried.
Power supply
After collecting the diodes, you need to think about applying voltage. Household current sources are not used; you need a special LED driver that supplies a pulsating stable current.
LED driver
LEDs do not require high voltage (220 Volts) for power supply; 3.2 – 12 Volts are enough for them. If you apply more voltage to the device, you can simply burn it. It is to eliminate such consequences that any spotlight must have an LED driver. Its purpose is to stabilize direct current.
For almost all homemade LED spotlights, a driver for LED strips or interior lighting systems is suitable. It is purchased in advance in ready-made form, the number of diodes is calculated according to the technical parameters and a circuit for their connection is developed. It will depend on the output voltage and stabilization current.
Power supplies
Such devices are used on spotlights that are built on LED matrices. For small devices of low power, you can use power supplies of general household value with an output pulsating current of 0.5 - 1.5 A, a voltage several volts higher than the direct voltage of the LEDs. To stabilize the current, LM317 microcircuits are used, and for devices of higher power - LM350, LM338.
Spotlight assembly steps
The procedure for creating the finished product is as follows:
- Prepare the case, remove all excess from the old cases to get an empty box, back trim with foil.
- If necessary, drill holes in the case for ventilation (when installing a radiator or cooler).
- Assemble all the LEDs together into one structure and secure them to the base (board).
- Bring the wires to the contacts and bring them out to the outside of the housing.
- Install the finished structure inside the body and secure it with glue.
- For a powerful spotlight, install the radiator together with the LED board (glue it).
- Pull the wires out and secure them with sealant (this will prevent moisture and dirt from getting inside).
To connect to the network, you must first connect the power cables to Right place. It is important not to reverse the polarity of the wires, otherwise the diodes may burn out or not work. A driver must be installed to stabilize the voltage. The joints of the wires are insulated with corrugation or a plastic cover. The finished structure is fixed on the street.
As a result of such actions, it will be ready homemade spotlight with directional lighting and high brightness. The downside is that with an unstable voltage, the reliability of the product will be lower, since surges can cause diodes to burn out. Mounting two resistors with a resistance of 1 - 2 Ohms will help correct this defect. This will allow you to get a truly high-quality design no worse than those sold in the store.
It was decided not to close the construction season this year, and since it gets dark early in the fall and especially in winter, a powerful light source is needed. Especially now that we are working on the facade, we need the light to illuminate the entire side of the facade. For this purpose there was made a powerful simple LED spotlight with your own hands.
We order the components and assemble a simple 50W floodlight with our own hands.
This simple LED spotlight took 5 minutes to make.
The peculiarity of this powerful matrix is that it does not require an LED driver. 220 volts is connected directly to it. At the same time, the price is very low, consider it a gift.
And so we choose more powerfully 50 Watt. Warm White - warm white (closer to incandescent in tone) or Cold White - cold white.
Let me tell you that 50 W is decent for LEDs.
The reverse side of the module is an aluminum substrate.
I took it without a lens. But for the next homemade spotlight I will definitely order with a lens. The fact is that the price will hardly change. The difference is about 20 rubles. A reflector is included with the lens.
Plus, contacts 220 need to be somehow isolated and covered, otherwise the lens will cover them.
This photo shows the matrix along with the lens and reflector.
For this LED module You definitely need a radiator. I just took a scrap of aluminum sheet (I had it in my bins). I drilled four 3mm holes in it for fastening the LED module and two more holes for fastening the wire with a tie (self-tightening strap).
On the reverse side of the LED module I applied a thin layer of thermal paste (residues from replacing the processor in the laptop).
Actually, everything is very primitive and can be seen in the photographs. Of course, it doesn’t look very civilized; you can’t hang one like that on a façade, but it’s just right for a construction site.
Don't forget that the 220V contacts are open! We will definitely isolate!
I filled it with varnish and stuck a film on top.
This is a type of mounting the LED matrix on the reverse side.
And here is a homemade spotlight in action. I don’t know if it shines at 50W, but it shines quite brightly. I tried to work at night, pointing the spotlight at the facade, everything was visible normally. The light spot covered the entire two-story façade.
Option for phytolamp.
By the way, these LED matrices are available with a special light spectrum for plants (seedlings). Moreover, one module contains the entire spectrum of light required by plants.