It is for lovers of "self-building" that we provide a step-by-step guide to making a miniature LED lamp, the current source for which will be a computer (desktop or laptop).
To implement this idea, we need the following components:
ultra-bright LED (color - optional) - 1 pc.;
resistor with a dissipating power of 0.5 W (resistance is calculated individually) - 1 pc.;
small-sized switch - 1 pc.;
old microphone - 1 pc.;
USB cable (length is selected based on needs).
The color of the LED light does not matter. In this case, its brightness is a priority characteristic. So, the cheapest component with a small operating current (10–20 mA) is also suitable, but its capabilities will probably not be enough to illuminate the workplace. We chose a white ultra-bright LED that is rated at 4V at 80mA. Recall that the longer output of this component for its proper functioning is connected to the "positive" pole of the power source, the short one - to the "negative".
The characteristics of the LED determine the required resistor value. It is calculated based on Ohm's law for the circuit section (R = U / I, where I is the operating current, U is the voltage in the circuit into which it will be connected). Since the voltage at the outputs of the USB port is 5 V, substituting the numbers in the formula, we got the calculated resistance value, in our case 62.5 ohms (R = 5 V / 0.08 A = 62.5 ohms). There was no resistor of this value at hand, so we used an element with a resistance of 68 ohms. In order to avoid failure of the LED, it is better to play it safe and take a resistor with a higher rating than vice versa. The quenching resistor is connected in series with the LED. If it is not there, the lamp will burn out after a few minutes of operation. Before we get down to business, we “arm ourselves” with the necessary tools - a soldering iron and accessories for it, a drill, a needle file, mounting wires, etc.
STEP 1
First, we disassemble the microphone and solder the only component present in it. In order not to complicate the work, you can use microphone wires to power the LED. We solder our "light bulb" to its proper place.
STEP 2
We cut off the end of the USB cable, leaving only a wire with a connector that will connect directly to the computer. We only need the red ("plus") and black ("minus") cores necessary to power the device. Part of the insulation must be removed from them and tinned before soldering inside the lamp.
STEP 3
With a suitable tool, we make several holes in the base of the microphone (for the USB wire, the cord going to the LED and the switch).
STEP 4
We mount the switch in the intended place, fixing it with glue or screws. The main thing is that the connection is made firmly and reliably. The red wire from the USB cable can be soldered to the center pin of the switch. After that, a resistor must be connected to one of the two remaining contacts. A wire is soldered to the other end of the resistance, going to the "positive" contact of the LED. When working, you must be as careful as possible and prevent a short circuit in the circuit. The wire soldered to the “minus” of our “light bulb” should be connected to the black core of the USB cable.
STEP 5
To reduce the risk of malfunctions in the circuit to a minimum (wire break, short circuit), the entire component base must be carefully insulated with a heat shrink tube, electrical tape, or a second “bottom” made of textolite or plexiglass should be made for the lamp-microphone stand, which will perform a protective function and increase stability of the device on the table.
RESULT
As a result, we got a pretty good mini-lamp powered by a computer USB port. The advantages of this solution include ease of manufacture, high brightness (in the case of using ultra-bright LEDs designed for high rated current) and a neat appearance.
Remember that this solution is just an example of the simplest backlight device that is easy to do with your own hands. If desired and the necessary skills, the design can be improved (for example, add a brightness control), complicate, change at your own discretion, based on the available components. In short, it all depends on your imagination.
The appearance of the USB lamp
In this article I will please you with one of the results of long reflections on the topic "where to apply the old, non-working keyboard." But as usual, think, don't think, but the idea won't come on purpose. An idea comes when you don’t expect it, and then don’t screw up, accept it royally. So in this case, working at night at a black keyboard and indeed at a computer, there is always a lack of lighting, especially when that very lighting is not very appropriate to turn on. I would like to become the owner of my own light source. That's when she came, the idea, gently whispered "keyboard ... light ...". Having thought a little, I got this design, a miniature USB lamp with super-bright LEDs to illuminate the keyboard and more.
The very principle of using the USB interface to power lamps and other devices for various purposes is not new. USB lamps, USB fans, USB hand warmers and many other devices have been on sale for a long time. Despite the highest reliability of keyboards, there are enough outdated and non-working among them, hands are itching to use them. Perhaps for toys () but better with benefit, for lighting. Thus, it was possible to use, if not the entire keyboard, but its parts in the form of buttons to create the original USB lamp.
I will not bore you with technical details, I will go straight to the description of this USB lamp. The lamp receives power from the USB interface, which is now in every computer, and also in the plural. The pinout of the pinouts of various options for the USB interface connectors can be viewed here (). Since the USB supply voltage is 5 V, and the drop on ultra-bright LEDs is slightly more than 3 V (depending on the type), a current-limiting resistor with a resistance of 100 ... 150 Ohms should be connected in series with each LED, and all LED-resistor chains should be connected in parallel and connected through the push button switch to the USB extension cable.
USB lamp in operation
In total, 6 keys were used to create the lamp. The base of the lamp is stable due to its shape, the central key plays not only an aesthetic role, but also a functional one, being an on / off key. Flexible mast allows you to change the direction of lighting in almost any direction. Of course, ultra-bright LEDs are not the best (spectral quality) source of illumination, but quite easy to use, they have extremely low energy consumption, for example, compared to such a lamp. This you can quite check in practice yourself.
The practical use of the USB lamp met all expectations, both as a backlight and in an aesthetic quality!
Now they don't celebrate housewarming. The tradition is lost. Before, guests were invited. Guests came with gifts, including a chandelier. It was difficult to buy a chandelier, they were produced too little. Now it is difficult to buy any lighting device, they produce too many - the eyes run up from the assortment. And when all design projects were implemented, and there were no free sockets left in the homes of citizens, there was one of the advanced ones who pointed a finger at computer sockets. Thus, a new product niche appeared. Niche LED .
I bought this as a future souvenir, for a lover of communicating with a netbook. Its full name is "FLARX USB LED Light". There is not much information on the package, but it is quite enough to make a choice. Composition: polystyrene, steel. LED life: 10,000 hours (which is impressive).
The openwork reflector in the form of flower petals immediately impresses, 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. Looks beautiful. However, it immediately becomes clear that thin Plexiglas petals will not last long.
In terms of overall dimensions, the lamp fits into the general view with a netbook, in terms of design it’s not very good, functionally it’s definitely not. The glow of the LED is so weak that it is impossible to see it at all with additional lighting. The verdict is simple - you need to do something.
It was not possible to remove the reflector with the help of the efforts of the fingers, a hacksaw blade was called to help, which made a circular cut in the holder. After that, he safely disconnected from the flexible element. The LED itself and its resistor, the current limiter, appeared before the eye. By measurement, the resistance of the resistor was set to 58 ohms. The way out is simple - you need to reduce. The reflector petals were not glued and were removed from its lens freely. The diameter of the spherical light-diffusing lens, also made of organic glass, is 24 mm.
New electrical circuit of the lamp
A suitable piece of plastic was put on the end of the flexible element, which was now free, which was intended to further play the role of a base for mounting a variable resistor. The fixed resistor, as an element of the circuit, was left, but its value was reduced to 23 ohms. A hole 2 mm in diameter was drilled in the side tide of the lens mount, through which wires were passed to connect with a variable resistor needed to regulate the strength of the luminous flux.
With a total resistance of 493 ohm limiting resistors (470 ohm variable and 23 ohm constant), the current through the LED is 4.3 mA. We get the minimum possible luminous flux. With the variable resistor turned to zero and, accordingly, only the resistance of the constant resistor of 23 ohms, the current on the LED is 47.3 mA. This is the maximum light output. Well, "true" - the best ratio of 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 to a variable resistor was not particularly difficult, as well as installing the resulting regulator in place. The inner 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.
Keyboard backlight in action: in a room in daylight and in a dark room. It is turned on at maximum brightness, it is quite possible to reduce it to normal.
Even now it is clear that if necessary, a netbook with such keyboard lighting can be fully exploited in this way. The beauty of the product has undoubtedly diminished, but it has become functionally suitable for the intended work. In general, I hurried with the purchase of this particular model at one time, now keyboards more suitable for the lighting function have appeared on sale. Review made Babay from Barnaula.
Discuss the article USB LIGHT FOR KEYBOARD LIGHT
A useful homemade product that will definitely come in handy almost anywhere where there is a USB:
- At home for illumination: you can connect even to a computer, even to a laptop.
- Hiking, fishing or hunting: you can connect to an external battery (power bank) and lighting in a tent or on the street is ready!
- In the car for lighting: now every radio has a USB input. If you make the wire longer, then you can generally use it as a mobile examination lamp.
- There are quite a few other uses as well.
- USB cable from any unnecessary charging.
- A pair of 5-500 ohm resistors - the resistance depends on the brightness of the LEDs.
- Non-working 220 V LED bulb.
Let's disassemble the light bulb. To do this, pry off the white dome with a flat screwdriver. It is glued on and should gradually move away from your pressure.
We remove the internal board, we will no longer need it, we will have our own.
We make a hole in the base for the wire with a hot soldering iron. You can just drill through.
We skip the wire to power the light bulb.
We now need to assemble a very simple circuit to power the LEDs from USB - 5V.
We do everything on a piece of plastic. My brightness is low, but if you want to be brighter, you need to do everything on an aluminum piece of metal. For better heat dissipation from LEDs. The resistance of the resistors can also regulate the power of the glow of the LEDs, and hence their heating.
We glue our assembled board to the light bulb. Glue on hot glue.
Now we collect the light bulb. Glass can be glued with super glue.
Here's what the finished USB-powered lamp looks like.
And here's how to glow. Almost like the lights before when it worked from 220 V. LEDs can be taken more powerful and more in number. But in this case, the current consumption will also increase, which may affect the USB load. I made the best choice.
Good day.
I think many of you have encountered a certain inconvenience when you need to work on your laptop or computer in the dark, because in the absence of external lighting in the room, against the background of a sufficiently bright screen, it becomes difficult to distinguish characters on the keyboard.
You have to look closely and strain your eyes. Some users manage to rotate the screen in such a way that the keyboard is illuminated due to it, but I think that this is not a way out of the situation and it will not work to get sufficient comfort when working at a computer in this way. An obvious solution to this inconvenience suggests itself - to purchase a special lamp to illuminate the keyboard, since retail chains provide a fairly large selection of such USB lamps at affordable prices.
I’ll make a reservation right away that the lamp was not ordered for myself and I don’t have a laptop, but I wanted to write a review.
The package arrived after 27 days.
Yellow postal envelope with a bubble wrap inside.
Package content:
1 - flexible leg
2 - lamp
The USB lamp consists of two parts - a flexible leg with connectors and the lamp itself.
The leg is made of metal and bends well. Can take almost any shape and hold it. The total length of the leg (including connectors) is 35 cm.
The lamp itself is made of aluminum alloy in the form of a profile.
Length 9.5 cm, Width 1.8 cm, Thickness 8 mm.
The luminaire has 8 bright LEDs.
I think that the observed lamp is suitable not only for illuminating the keyboard on a laptop, but also for illuminating the keyboard and desk of a stationary PC.
Pros:
An excellent device with bright LEDs for working at a computer in an unlit room, without disturbing others.
The flexible base will help you bend the lamp the way you want.
Lightweight, compact enough to take with you anywhere that fits in any bag.
Cons: not found.
I liked the device.
Thank you for your attention.
Enjoy the shopping.