LEDs for remote controls. IR LEDs: scope, types and main technical characteristics. Scheme of the receiving unit using IR radiation

Infrared remote controls have firmly taken their place in consumer electronics. Any equipment that is not equipped with this very convenient device includes televisions, stereo systems, microwave ovens, car CD/MP players, chandeliers and many many other things familiar to us.

Such a widespread use of remote controls could not help but affect their frequent breakdowns. Since it is sometimes difficult to purchase a new remote control needed for a specific device, they are sent in for repair.

How to quickly check the remote control?

The simplest and most effective method is to check remote controls using digital cameras. Nowadays, almost every cell phone has a digital camera.

Many laptops have a built-in webcam. For netbooks, a digital web camera is generally a mandatory attribute. Digital photo and video cameras are also suitable for testing remote controls. In general, any device that has even the simplest digital camera is suitable for testing the remote control.

To check the remote control, you only need to point the emitting infrared LED at the camera lens. On the digital display, when you press buttons on the remote control, periodic flashes of purple light will be visible. This indicates that the remote control is working properly.

The photo shows the flashes of an infrared LED captured by the camera of a Sony Ericsson K810i mobile phone.

If you don’t have devices with a digital camera at hand, you can use the following method.

Instead of an infrared LED, it is necessary to temporarily solder in a regular light-emitting diode. The LED can be of any color: red, green, yellow, white, in general, it doesn’t matter, the main thing is that the LED is 3 volts.

When you press the buttons on the remote control, a temporarily soldered ordinary LED will emit flashes of light. It should be noted that the brightness of the radiation will be low.

In the photo - a regular white LED, soldered in instead of an infrared one.

The remote control can be tested using an infrared photodiode and an oscilloscope.

In this case, an infrared photodiode is connected to the input of the oscilloscope. When the remote control is operating, pulses of short bursts will be visible on the oscilloscope screen. It is important that the photodiode is connected to the open input of the oscilloscope.

This is how simple and easy it is to check the functionality of any infrared remote control. To do this, it is not at all necessary to collect any sample circuits and clutter up the resulting overloaded workshop, because all the necessary tools are already at hand, especially a mobile phone with a camera

An infrared (IR) emitting diode is a semiconductor device whose operating spectrum is located in the near-infrared region: from 760 to 1400 nm. The term “IR LED” is often used on the Internet, although it does not emit light visible to the human eye. That is, within the framework of physical optics this term is incorrect, but in a broad sense the name is applicable. It is worth noting that during operation of some IR emitting diodes, a weak red glow can be observed, which is explained by the blurring of the spectral characteristics at the border with the visible range.

IR LEDs should not be confused with infrared laser diodes. The operating principle and technical parameters of these devices are very different.

Application area

Let’s take a closer look at what infrared LEDs are and where they are used. Many of us encounter them every day without knowing it. Of course, we are talking about remote controls (RC), one of the most important elements of which is the IR emitting diode. Due to its reliability and low cost, the method of transmitting a control signal using infrared radiation has become widespread in everyday life. These remote controls are mainly used to control the operation of televisions, air conditioners, and media players. When you press a button on the remote control, the IR LED emits a modulated (encrypted) signal, which is received and then recognized by a photodiode built into the body of the household appliance. In the security industry, video cameras with infrared illumination are very popular. Video surveillance, supplemented with IR illumination, allows you to organize round-the-clock monitoring of the protected facility, regardless of weather conditions. In this case, IR LEDs can be built into the video camera or installed in its working area in the form of a separate device - an infrared spotlight. The use of high-power IR LEDs in the floodlights allows for reliable control of the surrounding area.

Their scope of application is not limited to this. The use of IR emitting diodes in night vision devices (NVDs), where they perform the function of illumination, has proven to be very effective. With the help of such a device, a person can distinguish objects at a fairly large distance in the dark. Night vision devices are in demand in the military sphere, as well as for covert night surveillance.

Types of IR Emitting Diodes

The range of LEDs operating in the infrared spectrum includes dozens of items. Each individual specimen has certain characteristics. But in general, all IR semiconductor diodes can be divided according to the following criteria:

• radiation power or maximum forward current;
• purpose;
• form factor.

Low-current IR LEDs are designed to operate at currents of no more than 50 mA and are characterized by a radiation power of up to 100 mW. Imported samples are manufactured in 3 and 5 mm oval housings, which exactly replicate the dimensions of a conventional two-terminal indicator LED. Lens color ranges from transparent (water clear) to translucent blue or yellow. Russian-made IR emitting diodes are still produced in miniature packages: 3L107A, AL118A. High-power devices are produced both in DIP housing and using SMD technology. For example, SFH4715S from Osram in an smd housing.

Specifications

In electrical diagrams, IR emitting diodes are designated in the same way as LEDs, with which they have much in common. Let's look at their main technical characteristics.

Operating wavelength– the main parameter of any LED, including infrared. The passport for the device indicates its value in nm, at which the highest radiation amplitude is achieved.

Since an IR LED cannot operate at only one wavelength, it is customary to indicate the width of the emission spectrum, which indicates a deviation from the declared wavelength (frequency). The narrower the radiation range, the more power is concentrated at the operating frequency.

Rated forward current– direct current, at which the declared radiation power is guaranteed. It is also the maximum permissible current.

Maximum pulse current– current that can be passed through the device with a fill factor of no more than 10%. Its value can be ten times higher than direct direct current.

Forward voltage– voltage drop across the device in the open state when the rated current flows. For IR diodes, its value does not exceed 2V and depends on the chemical composition of the crystal. For example, UPR AL118A=1.7V, UPR L-53F3BT=1.2V.

Reverse voltage– the maximum voltage of reverse polarity that can be applied to the p-n junction. There are examples with a reverse voltage of no more than 1V.

IR emitting diodes of the same series can be produced with different scattering angles, which is reflected in their markings. The need for similar devices with a narrow (15°) and wide (70°) radiation flux distribution angle is caused by their different scope of application.

In addition to the basic characteristics, there are a number of additional parameters that should be taken into account when designing circuits for operation in pulsed mode, as well as in environmental conditions other than normal. Before carrying out soldering work, you should familiarize yourself with the manufacturer’s recommendations on observing the temperature regime during soldering. You can find out about the permissible time and temperature intervals from the datasheet for the infrared LED.

Read also

LEDs in remote controls rarely fail. Fortunately, anyone who knows how to hold a soldering iron can replace this element. You have absolutely correctly diagnosed the problem, but the lack of light may also indicate a breakdown of the quartz resonator, which happens much more often, since the resonator can fail when the remote control is dropped on a hard surface.

If you are sure that it is the LED that is faulty, then you can use a diode from another remote control or purchase a new one. The main parameters of IR LEDs are overall dimensions, angle and radiation power, and wavelength. In modern devices, only the dimensions of the element are decisive. The remaining parameters are not so significant. The maximum range of reliable operation or the need to accurately point the remote control at the device may change.

To replace the diode, you need a low-power soldering iron with a power of 25–40 W, no more, since when working with a powerful tool there is a high risk of peeling off the printed tracks. Also for work you need a small piece of low-melting solder (POS-60 or POS-90) and flux (for example, ordinary rosin). Under no circumstances should you use soldering acid used for soldering ferrous metals! The remote control will stop working in a couple of days, and the printed conductors will simply disappear in the solder joints.

When replacing an LED, the main thing is not to confuse the switching polarity. Typically, diodes have different terminal shapes. It makes sense to call them using the device if the switching polarity is indicated on the board. The diode conducts current when the positive probe is connected to the anode. Please note that not all instruments can be used to test LEDs.

The remote control for consumer electronic equipment is usually a small, battery-powered device with buttons that sends commands via infrared radiation with a wavelength of 0.75-1.4 microns. This spectrum is invisible to the human eye, but is recognized by the receiver of the receiving device. Most remote controls use one specialized command-former chip with a quartz resonator, packaged or unpackaged (placed directly on the printed circuit board and filled with compound to prevent damage), a signal amplifier consisting of one or two transistors, and an IR emitting diode (or two) range. Additionally, some remote controls also install an LED to indicate the sending of commands.

All over the world, the RC-5 remote control system is the most widely used for household radio equipment. This system was developed by Philips for the needs of controlling household equipment and is used in many televisions. A specialized transmitter chip is available for remote controls SAA3010 ( Integral software produces an analogue INA3010 ). The use of a specialized transmitter chip dramatically reduces the required number of components and allows the IR transmitter to be placed in a small package. In addition, such microcircuits solve the issue of low consumption in standby mode, which makes operating the remote control very convenient: there is no need for a separate power switch. The circuit goes into active mode when any button is pressed and returns tomicroconsumptionwhen releasing it. Currently, different manufacturers produce a large number of modifications of RC-5 remote controls, and some models have quite a decent design. Industrial remote controls are usually designed to control televisions. Therefore they use RC-5 code system 0. It’s not at all difficult to switch to a different system number, and then the mutual influence of different remote controls will be eliminated.

When we press the remote control button, the transmitter chip is activated and generates a sequence of pulses that have a filling frequency of 36 KHz. LEDs convert these signals into infrared radiation. The emitted signal is received by a photodiode, which again converts the IR radiation into electrical impulses. These pulses are amplified and demodulated by the receiver chip. They are then fed to the decoder. Decoding is usually done in software using a microcontroller. The RC5 code supports 2048 commands. These teams make up 32 groups (systems) of 64 teams each. Each system is used to control a specific device such as a TV, VCR, etc. One of the most common transmitter chips is the SAA3010 chip. The SAA3010 transmitter chip allows power supply voltage of +5V.

· Supply voltage – 2...7V

· Current consumption in standby mode – no more than 10 µA

· Maximum output current - ±10 mA

· Maximum clock frequency – 450 KHz

The block diagram of the SAA3010 chip is shown in Figure 1.

Figure 1. SAA3010 IC structure.

The description of the pins of the SAA3010 chip is given in the table:

The transmitter chip is the basis of the remote control. In practice, the same remote control can be used to control several devices. The chip can address 32 systems in two different modes: combined and single system mode. In combined mode, the system is selected first, and then the command. The number of the selected system (address code) is stored in a special register and a command related to this system is transmitted. Thus, to transmit any command, successive pressing of two buttons is required. This is not entirely convenient and is only justified when working simultaneously with a large number of systems. In practice, the transmitter is more often used in single system mode. In this case, instead of the matrix of system selection buttons, a jumper is mounted, which determines the system number. In this mode, transmitting any command requires pressing only one button. By using the switch, you can work with multiple systems. And in this case, only one button press is required to transmit the command. The command transmitted will be related to the system currently selected using the switch.

To enable the combined mode, a low level must be applied to the SSM (Single System Mode) transmitter output. In this mode, the transmitter IC operates as follows: During rest, the X and Z lines of the transmitter are driven high by internal p-channel pull-up transistors. When a button in the X-DR or Z-DR matrix is ​​pressed, the keyboard debounce cycle is initiated. If the button is closed for 18 clock cycles, the “oscillator enable” signal is fixed. At the end of the debouncing cycle, the DR outputs are turned off and two scan cycles are started, turning on each DR output in turn. The first scan cycle detects the Z address, the second scan detects the X address. When the Z-input (system matrix) or X-input (command matrix) is detected in the zero state, the address is latched. When you press a button in the system matrix, the last command (i.e., all command bits are one) in the selected system is transmitted. This command is transmitted until the system select button is released. When a button is pressed in the command matrix, the command is transmitted along with the system address stored in the latch register. If the button is released before transmission begins, a reset occurs. If the transfer has started, then regardless of the state of the button, it will be completed completely. If more than one Z or X button is pressed at the same time, the generator will not start.

To enable single system mode, the SSM pin must be high and the system address must be set with the appropriate jumper or switch. In this mode, the X-lines of the transmitter are in a high state during rest. At the same time, the Z-lines are turned off to prevent current consumption. In the first of two scan cycles, the system address is determined and stored in a latch register. In the second cycle, the command number is determined. This command is sent along with the system address stored in the latch register. If there is no Z-DR jumper, then no codes are transmitted.

If the button is released between code transmissions, a reset occurs. If the button is released during the debounce procedure or while the sensor is being scanned, but before the button is detected, a reset also occurs. Outputs DR0 – DR7 have an open drain, and the transistors are open at rest.

The RC-5 code has an additional control bit that is inverted each time the button is released. This bit informs the decoder whether the button is being held down or a new press has occurred. The control bit is inverted only after a completely completed transmission. Scanning cycles are carried out before each sending, so even if you change the pressed button to another during the sending of a parcel, the system number and commands will still be transmitted correctly.

The OSC pin is a 1-pin oscillator input/output and is designed to connect a ceramic resonator at a frequency of 432 KHz. It is recommended to connect a resistor with a resistance of 6.8 Kom in series with the resonator.

Test inputs TP1 and TP2 must be connected to ground during normal operation. When the logic level on TP1 is high, the scanning frequency increases, and when the logic level on TP2 is high, the frequency of the shift register is increased.

At rest, the DATA and MDATA outputs are in the Z-state. The pulse sequence generated by the transmitter at the MDATA output has a filling frequency of 36 kHz (1/12 of the clock generator frequency) with a duty cycle of 25%. The same sequence is generated at the DATA output, but without padding. This output is used when the transmitter chip acts as a controller for the built-in keyboard. The signal at the DATA output is completely identical to the signal at the output of the remote control receiver microcircuit (but unlike the receiver, it does not have inversion). Both of these signals can be processed by the same decoder.

The transmitter generates a 14-bit data word, the format of which is as follows:

· 2 start bits.

· 1 control bit.

· 5 bits of system address.

· 6 bit commands.

Figure 2. RC-5 code data word format.

The start bits are for setting the AGC in the receiver IC. The control bit is a sign of a new press. The clock duration is 1.778 ms. As long as the button remains pressed, a data word is transmitted at intervals of 64 clock cycles, i.e. 113.778 ms (Fig. 2). To ensure good noise immunity, two-phase coding is used (Fig. 3).

Figure 3. Encoding "0" and "1" in RC-5 code.

When using the RC-5 code, you may need to calculate the average current draw. This is quite easy to do if you use Fig. 4, which shows the detailed structure of the parcel.

Figure 4. Detailed structure of the RC-5 package.

To ensure that the equipment responds equally to RC-5 commands, the codes are distributed in a very specific way. This standardization allows transmitters to be designed to control a variety of devices. With the same command codes for the same functions in different devices, a transmitter with a relatively small number of buttons at a time can control e.g. audio complex, TV and VCR.

System numbers for some types of household equipment are given below:

0 - Television (TV)
2 - Teletext
3 - Video data
4 - Video Player (VLP)
5 - Video cassette recorder (VCR)
8 - Video tuner (Sat.TV)
9 - Video camera
16 - Audio preamp
17 - Tuner
18 - Tape recorder
20 - Compact player (CD)
21 - Turntable (LP)
29 - Lighting

The remaining system numbers are reserved for future standardization or experimental use. The correspondence of some command codes and functions has also been standardized.

The command codes for some functions are given below:

0-9 - Digital values ​​0-9
12 - Standby mode
15 - Display
13 - mute
16 - volume +
17 - volume -
30 - forward search
31 - search back
45 - ejection
48 - pause
50 - rewind
51 - fast forward
53 - playback
54 – stop
55 - entry

In order to obtain a complete IR remote control based on the transmitter chip, you also need an LED driver that is capable of providing a large pulse current. Modern LEDs operate in remote controls with pulse currents of about 1A.

It is very convenient to build an LED driver on a low-threshold (logic level) MOS transistor, for example, KP505A.

An example of a circuit diagram of the remote control is shown in Fig. 5.

Figure 5. Schematic diagram of the RC-5 remote control.

The system number is specified by a jumper between pins Zi and DRj.

The system number will be as follows: SYS = 8i + j

The command code that will be transmitted when pressing a button that closes line Xi with line DRj is calculated as follows: COM = 8i + j

Common malfunctions.

Problems with wireless remote controls

• dead batteries (the most common fault);
• the remote control is filled with some kind of liquid and the buttons either stick or won’t release;
• the quartz resonator or IR LED fell off (or was damaged) due to the impact;
• from frequent use, the conductive coating on the buttons themselves (or the conductors under the buttons) wears out;
• Dirt from hands that gets inside the remote control and accumulates over time.

There is no signal from the remote control.

First, check the health of the batteries. If the voltage on the element is less than 1.3V, it must be replaced. An ammeter measures the “short circuit” current of an element. If it is less than 300 mA, the element must also be replaced.

You can check the functionality of the remote control using any IR photodiode. Under the influence of IR radiation, a voltage appears at the photodiode terminals, which is recorded by an oscilloscope. The photodiode is placed opposite the remote control window. When you press the remote control buttons, pulses with a swing of 0.2...0.5V should appear on the oscilloscope.

Checking the remote control without special tools.
You can turn on the receiver to the “AM” band and press the button on the remote control, bring it close to the receiver, sounds (pulse packets) will be clearly audible from the speaker.
Another simple way to check the functionality of the remote control is as follows: turn on the camera on your mobile phone, point the remote control at the camera and press any button; if the remote control is working, the glow of the infrared emitter will be visible on the phone’s display.

If there is no signal, the remote control is faulty. They open it up. This operation requires certain skills and care so as not to leave scratches on the case or break the latches.

The printed circuit board is inspected, and the keyboard contacts remove traces of dried liquid in the form of a whitish coating from the printed circuit board and the contact field with a cotton swab moistened with alcohol. Cracks on printed conductors are eliminated by soldering jumpers made of tinned wire on top.

They control the quality of the soldering, and the absence of breakage of the leads of the parts, first of all this concerns the IR emitting diode and the quartz resonator. Then the operating modes are checked.

Measure the supply voltage (usually +3V) on the microcircuit. An oscilloscope is used to monitor the operation of the generator when a pair of button contacts is closed. If there is no generation, check the DC voltage +1...1.5V on the quartz resonator. If there is voltage, replace the resonators. If there is no constant voltage, check the serviceability of the microcircuit (by replacing it).

If generation is present, the following malfunctions are possible:

1. A leak appears in one of the pairs of keyboard contacts. Check with an ohmmeter. The resistance between the contacts of a working pair must be at least 100 kOhm. Otherwise, wipe the contacts with a cotton swab moistened with alcohol.

2. There is a leak from the graphite jumpers onto the printed conductors passing under the jumpers. To troubleshoot, the pins of the microcircuit connected to the keyboard contacts are unsoldered one by one. If generation stops when the next pin is unsoldered, check the circuits suitable for this pin. The printed conductor located under the graphite jumper is cut off on both sides and restored with a piece of insulated wire.

3. Dust, dirt, tin and rosin particles get in between the terminals of the microcircuit. Using a hard bristle brush and alcohol, wash the board between the terminals.

4. Microcircuit defect. If, after unsoldering its leads, the resistance of a pair of contacts increases to normal, the microcircuit is faulty. It needs to be replaced.

There is no signal from the remote control, but there is a pulse signal at the output of the microcircuit.

1. There is no supply voltage to the amplifier.

2. One of the amplifier transistors or the IR diode is faulty.

Troubleshooting begins by checking with an oscilloscope the presence of a pulse signal at the cathode of the IR radiation diode. If there is no signal and the DC voltage is zero, check the health of the diode. If it is working properly, and there is a constant voltage, but there is no signal, check the passage of the signal from the output of the microcircuit to the IR radiation diode, the serviceability of the transistors, and the presence of supply voltage.

The most common defects are: a malfunction of the amplifier's output transistor, a violation of the soldering of the terminals of the elements.

There is no signal from the remote control. There is a constant voltage across the IR diode. The batteries are quickly discharged.

The nature of the malfunction indicates that the IR diode is constantly open and a significant current flows through it, leading to the discharge of the elements.

Possible causes of the malfunction:

Breakdown of one of the amplifier transistors. Check with an ohmmeter.

The presence of two or more pairs of closed keyboard contacts. Check with an ohmmeter.

The microcircuit is defective. Check by replacement.

When the keyboard buttons are not pressed, a command is constantly received from the remote control.

Possible causes of the malfunction:

1. Reducing the insulation resistance between the terminals of the microcircuit or the contacts of the contact field. Eliminate by washing with alcohol.

2. Leakage from the graphite jumper onto the printed conductor running underneath it. The defective conductor is cut off at both ends and a piece of insulated wire is soldered on top.

3. The microcircuit is defective. Check by replacement.

One or more commands are not received from the remote control.

The cause of the defect may be an increase in the resistance of the closing contacts of the keyboard, dirt on the contact field, cracks on the board, or a malfunction of the microcircuit.

Using an ohmmeter, check the resistance of the conductive rubber contacts on the keyboard. For serviceable contacts it should be in the range from 2 to 5 kOhm. If the resistance exceeds 10 kOhm, the contacts are faulty. Before changing the entire rubber, you can try to restore the faulty contacts. To do this, the rubber keyboard is first cleaned of dirt by washing it under running hot water with soap and a brush. The faulty contact is then applied to a piece of writing paper and rubbed across it with a little force. Due to the roughness of the paper, a thin layer of dirt and oxides is removed from the contact. It is possible to use fine-grained sandpaper.

Another way to restore functionality is to stick circles of conductive rubber onto the faulty contacts. They are included in special repair kits for remote control units available for sale. Good results are obtained by gluing circles made of metal foil (from cigarettes). The paper-based foil provides a reliable adhesive connection to the rubber. Breaks in the conductors are eliminated by soldering jumpers. Cracks in the contact field are repaired by applying a layer of conductive adhesive (commercially available).

The remote control emits a command, but the TV does not respond to it. The TV is working fine.

Possible causes of the malfunction: a defect in the quartz resonator or microcircuit.

Check by replacement.

Common chipsP DU

Story

One of the earliest remote control devices was invented and patented by Nikola Tesla in 1893.
In 1903, the Spanish engineer and mathematician Leonardo Torres Quevedo presented the Telekino at the Paris Academy of Sciences, a device that was a robot that carried out commands transmitted via electromagnetic waves.

Remote control Zenith Space Commander 500, 1958
The first remote control for controlling a television was developed by the American company Zenith Radio Corporation in the early 1950s. It was connected to the TV with a cable. In 1955, the Flashmatic wireless remote control was developed, based on sending a beam of light towards a photocell. Unfortunately, the photocell could not distinguish the light from the remote control from light from other sources. In addition, it was necessary to point the remote control precisely at the receiver.

Remote control Zenith Space Commander 600
In 1956, Austrian-American Robert Adler developed the Zenith Space Commander wireless remote control. It was mechanical and used ultrasound to set the channel and volume. When the user pressed the button, it clicked and struck the plate. Each plate produced noise of a different frequency, and the television circuitry recognized this noise. The invention of the transistor made it possible to produce cheap electric remotes that contain a piezoelectric crystal that is powered by an electric current and oscillates at a frequency exceeding the upper limit of human hearing (though audible to dogs). The receiver contained a microphone connected to a circuit tuned to the same frequency. Some problems with this method were that the receiver could be triggered by natural noise and that some people could hear high-pitched ultrasonic signals.

In 1974, GRUNDIG and MAGNAVOX released the first color TV with an infrared microprocessor control. The TV had an on-screen display (OSD) - the channel number was displayed in the corner of the screen.
The impetus for more sophisticated types of remote controls came in the late 1970s when Teletext was developed by the BBC. Most remote controls sold at the time had a limited set of functions, sometimes only four: next channel, previous channel, volume up or down. These remote controls did not meet the needs of teletext, where pages were numbered with three-digit numbers. The remote control, which allowed you to select a teletext page, had to have buttons for numbers from 0 to 9, other control buttons, for example for switching between text and image, as well as regular television buttons for volume, channels, brightness, color. The first televisions with teletext had wired remotes for selecting teletext pages, but the growth in the use of teletext showed the need for wireless devices. And BBC engineers began negotiations with television manufacturers, which led in 1977-1978 to the appearance of prototypes that had a much wider range of functions. One of the companies was ITT, the infrared communication protocol was later named after it.
Apple's Stephen Wozniak founded CL9 in the 1980s. The company's goal was to create a remote control that could control multiple electronic devices. In the fall of 1987, the CORE module was introduced. Its advantage was the ability to “learn” signals from different devices. It also had the ability to perform certain functions at designated times thanks to a built-in clock. It was also the first remote that could be connected to a computer and loaded with updated software code. CORE hasn't had much of an impact on the market. It was too difficult to program for the average user, but it received rave reviews from people who were able to figure out its programming. These obstacles led to the dissolution of CL9, but one of its employees continued the business under the Celadon brand.
By the early 2000s, the number of household electrical appliances increased dramatically. To control a home theater, you may need five or six remote controls: from a satellite receiver, VCR, DVD player, television and sound amplifier. Some of them need to be used one after the other, and due to the fragmentation of control systems, this becomes cumbersome. Many experts, including renowned usability expert Jakob Nielsen and the inventor of the modern remote control, Robert Adler, have noted how confusing and clunky it can be to use multiple remotes.
The advent of PDAs with an infrared port made it possible to create universal remote controls with programmable control. However, due to its high cost, this method has not become very widespread. Special universal learning control panels have not become widespread due to the relative complexity of programming and use.

Sources.

Today in radio electronics there are a wide variety of products used to create high-quality and effective lighting. One such product is an infrared diode type.

To use it to create backlighting, you need to know not only where they are used, but also their features. This article will help you understand this issue.

Features of diodes operating in the infrared range

Infrared LEDs (abbreviated as IR diodes) are semiconductor elements of electronic circuits, which, when current passes through them, emit light in the infrared range.

Note! Infrared radiation is invisible to the human eye. This radiation can only be detected by using stationary video cameras or mobile phone video cameras. This is one way to check whether a diode operates in the infrared spectrum.

High-power LEDs (for example, laser type) in the infrared spectral range are produced on the basis of quantum-sized heterostructures. An FP type laser is used here. As a result, the LED power starts at 10 mV, and the limiting threshold is 1000 mV. Housings for this type of product are suitable for both 3-pin and HHL types. As a result, the radiation appears in the spectrum from 1300 to 1550 nm.

IR Diode Structure

As a result of this structure, a high-power laser diode serves as an excellent source of radiation, due to which it is often used in fiber-optic information transmission systems, as well as in many other areas, which will be discussed below.
The infrared laser diode type is a source of powerful and concentrated laser radiation. In its work, the laser principle of operation is used.
Power diodes (laser type) have the following technical characteristics:

Note! Due to the fact that the product emits light in the infrared range, such familiar characteristics as illumination, power of emitted light flux, etc. don't fit here.

Graphic display of solid angle in 1 sr

• such LEDs are capable of generating waves in the range of 0.74-2000 microns. This range serves as the limit when radiation and light have a conditional division;
• power of generated radiation. This parameter reflects the amount of energy per unit time. This power is additionally tied to the dimensions of the emitter. This parameter is measured in W per unit of available area;
• intensity of the emitted flux within the frame of the volumetric angle segment. This is a rather conditional characteristic. It is due to the fact that, with the help of optical systems, the radiation emitted by the diode is collected and then directed in the required direction. This parameter is measured in watts per steradian (W/sr).

In some situations, when there is no need for a constant flow of energy, but pulsed signals are sufficient, the above-described structure and characteristics make it possible to increase the power of energy emitted by a radio circuit element several times.

Note! Sometimes in the characteristics of infrared diodes, indicators for continuous and pulsed operating modes are distinguished.

How to check functionality

Checking the IR diode

When working with this element of the electrical circuit, you need to know how to check its operation. So, as already mentioned, you can visually check the presence of this radiation using video cameras. Here you can evaluate performance using conventional mobile phone video cameras.
Note! Using video cameras is the easiest way to check.

This IR element in the remote control is easy to check; you just need to point it at the TV and press the button. If the system is working properly, the diode will flash and the TV will turn on.
But you can empirically check the performance of such an LED using special equipment. A tester is suitable for these purposes. To test an LED, the tester should be connected to its terminals and set to the mOm measurement limit. After that, we look at it through a camera, for example through a mobile phone. If a beam of light is visible on the screen, then everything is in order. That's the whole test.

Scope of application of IR diodes

At this point in time, infrared LEDs are used in the following areas:

• in medicine. Such elements of radio circuits serve as a high-quality and effective source for creating directional illumination for a variety of medical equipment;
• in security systems;
• in an information transmission system using fiber optic cables. Due to their special structure, these products are capable of working with multimode and single-mode optical fiber;
• research and scientific spheres. Such products are in demand in the processes of pumping solid-state lasers during scientific research, as well as illumination;
• military industry. Here they have the same wide application as illumination as in the medical field.

In addition, such diodes are found in various equipment:

• devices for remote control of equipment;

IR diode in the remote control

• various control and measuring optical instruments;
• wireless communication lines;
• switching optocoupler devices.

As you can see, the scope of application of this product is impressive. Therefore, you can purchase such diode components for your home laboratory without any problems; they are sold in abundance on the market and in specialized stores.

Conclusion

Today there is no doubt about the effectiveness of high-power infrared LEDs. This is confirmed by the fact that such elements of electrical systems have a wide range of applications. Due to their structure, IR LEDs are distinguished by impeccable performance characteristics and high-quality work.

How to make a ceiling wooden chandelier with your own hands
LED color temperature indicator
Why you should pay attention to lamps on rods