Probably everyone is familiar with the situation when you have to work at a laptop (typing text, or processing other information) in the dark, but for one reason or another you cannot turn on the light.

Something made by yourself will help you cope with this problem. laptop keyboard backlight. Without exaggeration, anyone who is at least a little familiar with electronics and can hold a soldering iron can make it. So, fewer words, it's time to get down to business.

To work, we will need: soldering accessories, a resistor with a resistance of 820 ohms, a ferrite ring (can be taken from any motherboard, or computer unit power supply), a little cross cutting, heat shrink tube, thick wire, any npn transistor, in my case KT3102, bright white LEDs, you can use standard round ones. Or maybe not just LEDs, as in my case. I had a broken matrix from a laptop, and I used part of the backlight strip from it.

Let's start manufacturing by winding the transformer (if you can call it that) on a ferrite ring. To do this, you need to evenly lay 18–22 turns of wire around the entire perimeter of the ring. You need to wind with two wires at the same time; for convenience, it is better to take wires with insulation of different colors. The end result will be something similar to this:

Next, connect the end of the white wire to the beginning of the blue one. The plus will be connected to this solder USB connector A. We connect the beginning of the white wire through a resistor (it is necessary to install it, otherwise the transistor will heat up, and the transformer will whistle and nothing will work) to the base of the transistor. By the way, the pinout of the transistor, if you look at it not from the cut side, is emitter base collector. We connect the collector to the end of the blue wire. Later, the minus from the USB connector will be connected to the emitter. The LED strip is connected with a plus to the collector and a minus to the emitter. The design of this homemade lighting device is simple and clear, so I am not attaching a diagram.

All the nuances are visible and understandable from the photo. Other rants about the design of this homemade product - laptop keyboard backlight inappropriate. Everyone will work out the design and construction for themselves. Based on available materials. Don't limit your imagination.

To illuminate your computer keyboard, you don’t have to buy a portable LED module. You can solve the issue yourself using one or more LEDs, a resistor and a USB connector. The entire structure can be easily assembled with your own hands in a matter of minutes. More sophisticated PC users can make a USB backlight from an LED strip. But first things first.

USB pinout

Everyone knows that when a phone is connected to a computer, it starts charging. This fact suggests that on USB contacts There is voltage present that can be used to power the LED. A standard USB 2.0 connector has 4 contacts, two of which are needed for data transfer, and two for powering the connected device. Detailed USB pinout 2.0 is shown in the figure. Standard load capacity USB port The current is 500 mA and the voltage is 5V, which allows you to connect a whole line of low-current LEDs to the connector.

Connection diagram

The USB connector is perhaps the main part of the assembled structure. You can buy it in a collapsible case or use an unnecessary but working cord from any peripheral device. Depending on distance system unit from the location where the backlight is installed, you need to calculate the length of the wire. Some keyboard models have an additional USB connector on the side, which can be used to provide backlighting.

LED

The connection diagram for one LED is shown in the figure. To implement it, you will need a USB connector, a resistor, a two-wire wire and a high-brightness LED. If the USB plug was purchased separately, it must be disassembled, freeing the internal part with solder contacts. Having decided on the LED, calculate the resistor resistance:

R=(U PIT -U LED)/I LED,

U PIT – supply voltage from the USB port equal to 5V;
U LED – forward voltage LED, which depends on the color of the glow;
I LED – rated operating current of the LED.

You can read more about how to correctly select and calculate a current-limiting resistor.

Now all that remains is to properly solder all the existing parts together and give the backlight an attractive look. First, using wire cutters, shorten the positive terminal of the LED and solder a resistor to it. Next, one wire is soldered to the free terminal of the resistor, and the second wire is soldered to the negative terminal of the LED. The leads, resistor and soldering points are hidden under a heat-shrinkable tube. To give a decent appearance A larger diameter thermal tube is placed on both wires near the LED. On the reverse side, the connecting cord is soldered to the terminals of the disassembled USB connector. The wire coming from the resistor is connected to terminal No. 1 (+5V), and the wire coming from the minus of the LED is connected to terminal No. 4 (GND). Check that after soldering there is no short circuit with the second and third terminals and assemble the connector.

If a ready-made USB cord with a connector is used, then the free ends of the wires are stripped and the two outermost supply wires are connected using a multimeter. Then they are soldered to the LED through a resistor using the above method. Unused data lines are shortened and insulated to avoid short circuit. Now the backlight is ready for use.

LED strip

To make the backlight have a higher luminous efficiency, use LED strip. This is especially true for lighting the retractable shelf of a computer desk. The LED strip is glued to the edge under the tabletop, ensuring a uniform light flux on the surface of the keyboard. To power the tape from a USB port, you will additionally need a boost converter from 5 to 12 volts, which you will have to make yourself or purchase at an electronics store.

But it's easier to go the other way. The computer power supply produces the necessary +12V, which is present on the 4-wire molex connector inside the system unit. All that is required is to buy a mating molex connector with pins, solder a power wire of the required length to it and to the LED strip, which is routed through the rear wall of the system unit. The plus of the tape is connected to the yellow molex wire, and the minus to any black one.

The load capacity of the +12V bus of a computer power supply is tens of times greater than that of USB, which makes it possible to make the keyboard backlight of the desired brightness.

Read also

In this material we present to your attention an overview of the most interesting idea for making a USB backlight for a laptop keyboard.

We will need:
- glue gun;
- soldering iron;
- USB plug;
- cap from a plastic bottle;
- tester;
- Light-emitting diode;
- 100 Ohm resistor.

First of all, we take a tester and determine which resistor is suitable for us to make the backlight.

Take a USB plug. The first and fourth pins of the plug are positive and negative. The second and third contacts are for data transfer. Let's start assembling.

Solder the resistor to the negative terminal. The polarity of the resistor does not matter in this case.

Let's move on to the LED. The positive side of the LED is called the anode, and the negative side is called the cathode. On new LEDs, the anode leg is longer than the cathode leg. If you are using an LED that has been previously used, then the polarity can be distinguished by the sawn-off skirt or bed of the crystal, which is located on the cathode.

Solder the negative of the LED to the resistor.

We solder the positive leg of the LED to the positive contact of the USB plug.

We insert the plug into the connector and check the assembly for functionality.

We put a mark on the plug, bend the resistor and LED into the desired position, fill the cap of a plastic bottle with hot glue and immerse the resistor with the LED light bulb and plug up to the mark.

The lighting itself is ready. If desired, you can paint it with spray paint.

Connecting LEDs to USB and other computer connectors

The use of LEDs in modding is very popular due to the low complexity of their connection and the good visual effect obtained from their use. It is for this reason that we bring to your attention a practical guide on connecting LEDs in a computer. This guide is aimed at modders who are just starting to use LEDs in their modding projects and in it I will talk about the three most popular methods power connections to LEDs, depending on connector: from 4-pin molex, from 3-pin or from USB.

Necessary: To accomplish this LED connection guide we will need the following things:

• LEDs. Everything is clear here; in fact, we will connect them.)
• Resistors. Necessary for reducing the voltage and current from the power source to the values ​​required by the connected LED.
• Connectors. These LEDs will be connected to power supplies in the computer.
• Soldering iron with everything needed for soldering.
• Heat-shrink tubing. Needed to ensure a neat appearance and safety of the soldered joint.
• Multimeter(tester). To check voltages and connection integrity.
• Wire cutters and/or blade. For stripping and working with wires.

As can be seen from the list above, we do not need any complex, expensive or cunning devices to complete this guide. And the operation itself of connecting LEDs is also not particularly difficult. Go to details description in various ways connecting LEDs in a computer. Connecting an LED to a 4-pin molex4-pin connector Molex is one of the most common power connectors in a computer. It was with the help of molex connectors that previously (and even now in older models) power was connected to hard drives and optical drives. Also, some fans and most computer accessories, such as control panels, backlights and similar devices, are connected using Molex connectors. As its name suggests, 4-pin molex contains four contacts: + 12 B (usually the yellow wire), + 5 B (usually a red wire), as well as two ground contacts (black wires). Accordingly, when connecting an LED to a 4-pin molex, you have the opportunity to choose where exactly to connect the LEDs, namely to 12 or 5 volts.

In our case, I will connect a four-crystal 10mm green LED, which runs from 3.2 volt and consumes 80 mA to 12 volt source. We need a resistor with a resistance of 120 Ohm. The connector itself 4-pin molex You can either buy it separately, or use a connector taken from something old/unnecessary device, such as an extension cord, splitter, or adapter.

Before connecting the LED, it is advisable to first check the correspondence of the selected contacts with a multimeter, and also determine where the LED has positive (plus) and negative (minus) contacts. After this, you need to strip the wires that come from the molex connector and solder a resistor to the positive contact, not forgetting to cover the soldered joint with heat shrink tubing. After this, it is necessary to solder the positive contact of the LED to the other contact of the resistor, also covering the soldering area with heat shrink. The negative contact of the LED is soldered to the ground contact of the molex connector, and the soldering area is once again covered with heat-shrinkable tubing. Now everything is ready and you can safely connect the LED to power to check its functionality. Let's check - everything works!

Connecting an LED to a 3-pin connector

Connector 3-pin is a standard connector for connecting fans in a computer and quite often they remain superfluous, so you can connect an LED to them. This is sometimes done when installing water blocks with transparent covers on a processor, because there is no longer a need to connect a processor cooler fan, and you don’t want to pull a wire to connect an LED from somewhere far away - you can use a 3-pin connector. The described method of connecting LEDs is practiced, for example, by Thermaltake with its processor water blocks, which have a transparent cover. As its name implies, the 3-pin connector has three contacts: + 12 V, ground, as well as the third contact, which is the contact of the fan speed sensor.

In our case, to the connector 3-pin I will connect a 10mm red LED, which operates at 2.3 volts and draws 50 mA to a 12 volt source. To connect the LED- we need a resistor with a resistance of 220 O m. As you should already understand, to connect the LED we will use two contacts, namely +12 V and ground. It is worth remembering that 3-pin connectors are intended for connecting fans, so they are better do not load too much, however, a few watts of additional load will not create a problem, and for LEDs they will be enough with a reserve. You can either buy 3-pin connectors or use a connector taken from some old/unnecessary device, such as a fan, extension cord, adapter or splitter.

Before connecting the LED to the connector 3-pin It is advisable to additionally check the correspondence of the selected contacts with a multimeter, and also determine where the positive (plus) and negative (minus) contacts of the LED are. Now you need to strip the wires that come from the 3-pin connector and solder a resistor to the positive contact, covering the soldered joint with heat shrink tubing for better appearance and safety. It is necessary to solder the positive contact of the LED to the second contact of the resistor and also cover the soldering area with heat shrink. The negative pin of the LED is soldered to the ground pin at the 3-pin connector, and once again the soldering area is covered with heat-shrink tubing. Now everything is ready, you can safely connect the 3-pin connector to the power supply to check the functionality of the LED. Let's check - everything works as expected!

Connecting the LED to the USB connector

For those who don't know, USB is a data transfer interface for peripheral devices, however, in addition to the data in USB connector transmits power supply voltage different devices. To be precise, the USB connector has four contacts: two contacts are responsible for data transfer and two more for power. The USB connector provides a 5 V voltage source with a current of up to 500 mA. USB connectors are rarely sold separately, so the easiest way would be to buy a USB cable or take a cable you don’t need from some device. Full-size USB connectors come in two types, which differ in size: USB type A - 4 x 12 mm USB type B - 7 x 8 mm All the differences are only in the shape; in terms of available contacts, they are the same. In my case, I used a USB extension cable with USB connectors type A.

Nowadays housewarming is not celebrated. The tradition is lost. And before they invited guests. Guests came with gifts, including a chandelier. It was difficult to buy a chandelier; there were too few of them produced. Nowadays it’s difficult to buy any lighting device; they produce too many of them - your eyes run wild from the assortment. And so, when all the design projects were implemented, and there were no free sockets left in citizens’ homes, there was one of the advanced ones who pointed his finger at computer sockets. This is how a new product niche emerged. LED niche.

I bought this as a future souvenir for someone who likes to communicate with a netbook. Its full name is “FLARX USB LED lamp”. There is not a lot of information on the packaging, but it is quite enough to make a choice. Composition: polystyrene, steel. LED lifespan: 10,000 hours (which is impressive).

The openwork reflector in the shape of flower petals immediately makes an impression; its diameter is 85 mm, the total length of the lamp is 350 mm, the thickness of the flexible element is 5 mm, the USB plug is standard. It looks beautiful. However, it immediately becomes clear that the thin plexiglass petals will not last long.

The overall dimensions of the lamp are general form It fits in with the netbook, not very well in terms of design, definitely not functionally. The LED glow is so weak that with additional lighting it cannot be seen at all. The verdict is simple - something needs to be done.

It was not possible to remove the reflector using the force of the fingers; a hacksaw blade was called in to help, which made a circular cut in the holder. After which it was safely disconnected from the flexible element. The LED itself and its resistor - the current limiter - appeared. The measurement established the resistance of the resistor - 58 Ohms. The solution is simple - you need to reduce it. The reflector petals were not glued and were removed from its lens freely. The diameter of the spherical light-scattering lens, also made of organic glass, is 24 mm.

New electrical circuit of the lamp

A certain suitable plastic part was put on the now free end of the flexible element, which was intended to subsequently act as a base for attaching a variable resistor. The constant resistor, as a circuit element, was left, but its value was reduced to 23 Ohms. A hole with a diameter of 2 mm was drilled in the side boss of the lens mount, through which connection wires with a variable resistor needed to regulate the strength of the light flux were passed.

With a total resistance of the limiting resistors of 493 Ohms (variable 470 Ohms and constant 23 Ohms), the current on the LED is 4.3 mA. We obtain the minimum possible luminous flux. With the variable resistor turned to “zero” and, accordingly, only the resistance constant resistor at 23 ohms the current across the LED is 47.3 mA. This is the maximum luminous flux. Well, the “truth” - best ratio the load on the LED and the illumination will be somewhere in the middle.

The base for mounting the LED is hollow; drilling holes in it, passing wires through them, and then soldering it to a variable resistor was not particularly difficult, as was installing the resulting regulator in place. The internal cavity was filled with Titan glue. In conclusion, a kind of lampshade was made and installed; it has no reflective abilities, but it will save the eyes from unnecessary light.

The keyboard backlight is in action: in a room in daylight and in a dark room. It is turned on at maximum brightness, it is quite possible to turn it down to normal.

It is already clear that, if necessary, a netbook with such keyboard lighting can be fully operated in this way. The beauty of the product has undoubtedly diminished, but it has become functionally suitable for the intended work. In general, I was in a hurry to buy this particular model; now more suitable keyboard lighting functions have appeared on sale. Review made Babay iz Barnaula.

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