A single-channel receiver module with a relay, for operation from any standard infrared remote control, provides remote control of any load via an invisible IR channel. The project is based on the PIC12F683 microcontroller and the TSOP1738 is used as an infrared receiver. The microcontroller decodes the RC5 serial data project from the TSOP1738 and controls the output if the data is valid. The output can be set to various required states using a jumper on the board (J1). There are 3 LEDs on the PCB: power indicator, transmission presence and relay actuation. This circuit works with any RC5 remote control from TV, center and so on.
Features of the scheme
- Receiver power supply 7-12V DC
- Receiver current consumption up to 30 mA
- Radius up to 10 meters
- RC5 signal protocol
- Board dimensions 60 x 30 mm
Although recently it has become fashionable to use a radio channel, including Bluetooth, it is not at all easy to make such equipment on your own. In addition, radio waves are subject to interference, and it is elementary to intercept them. Therefore, IR signal will be preferable in some cases. Firmware, PCB drawings and full description in English -
In household electronic equipment, integrated infrared receivers are widely used. In another way, they are also called IR modules.
They can be found in any electronic device that can be controlled by a remote control.
For example, an IR receiver on the printed circuit board of a TV.
Despite the seeming simplicity of this electronic component, it is a specialized integrated circuit designed to receive an infrared signal from remote controls (RC). As a rule, an IR receiver has at least 3 pins. One pin is common and connects to minus «-» food ( GND), the other serves as a positive «+» conclusion ( Vs), and the third is the output of the received signal ( Out).
Unlike a conventional infrared photodiode, an IR receiver can receive and process an infrared signal, which is IR pulses of a fixed frequency and a certain duration - a burst of pulses. This technological solution eliminates accidental alarms that can be caused by background radiation and interference from other devices emitting in the infrared range.
For example, fluorescent lighting lamps with electronic ballasts can greatly interfere with the IR receiver. It is clear that you cannot use an IR receiver instead of a conventional IR photodiode, because the IR module is a specialized microcircuit, sharpened for specific needs.
In order to understand the principle of operation of the IR module, let's take a closer look at its structure using a block diagram.
IR receiver microcircuit includes:
PIN photodiode
Adjustable amplifier
Band pass filter
Amplitude detector
Integrating filter
Threshold device
PIN photodiode Is a kind of photodiode that has n and p a region of its own semiconductor is located ( i-region ). The area of \u200b\u200ban intrinsic semiconductor is essentially a layer of pure semiconductor without impurities introduced into it. It is this layer that gives the PIN diode its special properties. By the way, PIN diodes (not photodiodes) are actively used in microwave electronics. Take a look at your cell phone, it also uses a PIN diode.
But, back to the PIN photodiode. In the normal state, no current flows through the PIN photodiode, since it is included in the circuit in the opposite direction (in the so-called reverse bias). Since under the influence of external infrared radiation in i-regions electron-hole pairs arise, then as a result, a current begins to flow through the diode. This current is then converted into voltage and supplied to adjustable amplifier.
Then the signal from the adjustable amplifier is fed to band pass filter... It serves as protection against interference. The bandpass filter is tuned to a specific frequency. So in IR receivers, bandpass filters are mainly used, tuned to a frequency of 30; 33; 36; 36.7; 38; 40; 56 and 455 kilohertz. In order for the signal emitted by the remote control to be received by the IR receiver, it must be modulated with the same frequency to which the IR receiver bandpass filter is set. This is how, for example, a modulated signal from an emitting infrared diode looks like (see figure).
And this is how the signal at the output of the IR receiver looks like.
It should be noted that the selectivity of the bandpass filter is low. Therefore, an IR module with a 30 kilohertz filter can easily receive a signal with a frequency of 36.7 kilohertz or more. However, in this case, the distance of confident reception is noticeably reduced.
After the signal has passed through the bandpass filter, it goes to amplitude detector and integrating filter... An integrating filter is needed to suppress short single bursts of the signal that can be caused by noise. Then the signal goes to threshold deviceand then on output transistor.
For stable operation of the receiver, the gain of the variable amplifier is controlled by the automatic gain control system ( AGC). Since the useful signal is a burst of pulses of a certain duration, due to the inertia of the AGC, the signal has time to pass through the amplification path and the rest of the circuit nodes.
In the case when the duration of the burst of pulses is excessive, the AGC system is triggered and the receiver stops receiving the signal. Such a situation can arise when the IR receiver is illuminated by a fluorescent lamp with electronic ballast, which operates at frequencies of 30-50 kilohertz. In this case, the modulated infrared radiation of mercury vapor from the lamp can pass the protective band-pass filter of the photodetector and trigger the AGC. Naturally, in this case, the sensitivity of the IR receiver decreases.
Therefore, do not be surprised when the TV's photodetector does not receive commands from the remote control well. Perhaps he is simply disturbed by the illumination of fluorescent lamps.
Automatic threshold adjustment ( ARP) performs the same function as AGC, controlling the threshold of the threshold device. ATM sets the threshold level in such a way as to reduce the number of false pulses at the module output. In the absence of a useful signal, the number of false pulses can reach 15 per minute.
The shape of the body of the IR module facilitates focusing of the received radiation onto the sensitive surface of the photodiode. The housing material transmits radiation with a wavelength of 830 to 1100 nm. Thus, an optical filter is implemented in the device. To protect the receiver elements from external electric fields, an electrostatic shield is installed in the module. The photo shows the brand's IR modules HS0038A2 and TSOP2236... For comparison, ordinary IR photodiodes are shown next to KDF-111V and FD-265.
IR receivers
How to check if the IR receiver is working properly?
Since the receiver of IR signals is a specialized microcircuit, in order to reliably check its serviceability, it is necessary to apply a supply voltage to the microcircuit. For example, the nominal supply voltage for the “high voltage” IR modules of the TSOP22 series is 5 volts. The consumed current is in units of milliamperes (0.4 - 1.5 mA). When connecting power to the module, take into account the pinout.
In a state when a signal is not supplied to the receiver, as well as in pauses between bursts of pulses, the voltage at its output (without load) is practically equal to the supply voltage. The output voltage between the common terminal (GND) and the signal output terminal can be measured with a digital multimeter. You can also measure the current consumed by the module. If the current consumption exceeds the typical one, then the module is most likely defective.
Read about how to check the serviceability of the IR receiver using a power supply, multimeter and remote control.
As you can see, the infrared receivers used in infrared remote control systems have a rather sophisticated device. These photodetectors are often used in their homemade devices by lovers of microcontroller technology.
Among devices designed for remote control and monitoring, devices using infrared (IR) radiation have a long and honorable place.
For example, the first infrared remote controls appeared in 1974 thanks to the firms Grundig and Magnavox, who released the first television equipped with such a control. Infrared sensors are widely used in automation.
The main advantage of infrared control devices is their low sensitivity to electromagnetic interference, as well as the fact that these devices do not themselves interfere with other electronic devices. Typically, infrared remote control is limited to residential or industrial premises, and the emitter and receiver of infrared radiation must be in line of sight and directed towards each other.
These properties determine the main field of application of the considered devices - remote control of household appliances and automation devices at short distances, as well as where contactless detection of the intersection of the straight-line propagation of radiation is required.
Even at the dawn of their appearance, infrared devices were very simple to develop and use, but at the present time, when using a modern electronic base, such devices have become even simpler and more reliable. As you can easily see, even mobile phones and smartphones are equipped with an infrared port for communication and control of household appliances via infrared, despite the widespread use of wireless technologies such as Bluetooth and Wi-Fi.
Master Kit offers several infrared modules for DIY projects.
Consider three devices of varying degrees of complexity and purpose. For convenience, the main characteristics of all devices are summarized in the table at the end of the review.
- The infrared barrier is intended for use as a sensor for security systems, for sports competitions as a photo finish, as well as for remote control of automation devices at a distance of up to 50 meters.
The device consists of two modules - a transmitter and a receiver. The transmitter is assembled on a dual integral timer NE556 and generates square-wave pulses with a filling frequency of 36 kHz. The timer has a powerful enough current output to directly control the infrared LEDs connected to it.
A single analogue of NE556 is the famous NE555 integral timer, which has been serving a whole army of radio amateurs for the development of electronic devices for many decades. You can study the timer on examples of 20 electronic circuits, developed on the basis of this timer, using the "Classics of Circuit Engineering" kit-constructor of their ABC series. When assembling circuits, you don't even need a soldering iron; they are all assembled on a solderless breadboard.
The emitted signal is received by a receiver based on a specialized microcircuit, detected by a peak detector and fed to a current amplifier on a transistor to which a relay is connected, which allows switching current up to 10A.
The infrared barrier, in spite of its simplicity, is a rather sensitive device, and allows it to work both for "transmission" and for "reflection" and requires the manufacture of hoods for the transmitter and receiver, eliminating the influence of reflected signals.
An example of the use of an infrared barrier in conjunction with the "Digital laboratory" set from the already mentioned ABC series can be viewed.
- Is a light switch controlled by any infrared remote control.
The module allows you to control lighting or other electrical appliances using any button on the remote control.
Typically, each remote control has rarely used or not used buttons at all. Using this switch, you can turn on and off the chandelier, fan, etc. from the same remote control from which you control your TV or music center.
When power is applied, the module "waits" for 10 seconds to receive a signal corresponding to the selected button on the remote control, and after this time expires, "remembers" the pressed button. After that, to activate the module relay, it is enough to press this button once; when pressed again, the relay will turn off. Thus, the "trigger" control mode is realized. The module remains programmed even if its power is turned off.
It should be noted that the module "remembers" its last state when the power is turned off.
The device provides a mode of automatic shutdown of the load approximately 12 hours after turning it on, in case the load is forgotten to turn off.
The module relay can switch power up to 1500 W.
- The set of wireless infrared control has its own remote control with 4 buttons and 4 control channels, 2000 W each.
Each of the 4 remote control channels operates in the "button" mode, i.e. the channel relay is closed while the corresponding button on the remote control is pressed.
With the help of the module it is possible to organize reverse control of two collector motors, since each relay has one normally closed (NC) and one normally open (NO) contact with a common wire.
For ease of use, each channel is equipped with an LED that indicates relay activation.
The remote control of the kit is powered by the CR2032 element.
Load control with higher power for all considered devices can be carried out using expansion modules:
Up to 4000 W: expansion module will do;
Up to 8000 W: Expansion module will do.
Infrared modules
vendor code | Name | Supply voltage | Number of control channels | Maximum load power of one channel, W | Application examples |
Infrared barrier | 12V DC | Security devices; sport competitions; robotics; automation devices |
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Light switch | 12V DC; 220V variable | Lighting, ventilation, heating control |
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Wireless control kit | 12V DC | Reversible control of collector motors; 4-channel control of household appliances |
The remote control of a video recorder, TV, music center or satellite receiver can be used to turn off and on various household electrical appliances, including lighting.
Do-it-yourself remote control will help us with this, the diagram of which is given in this article.
Description of the operation of the IR remote control system
The following mechanism is used for remote control of devices. On the remote control, press and hold an arbitrary button for 1 second. The system does not respond to a short press (for example, when operating the music center).
In order to exclude the response of the TV to the control of devices, it is necessary to select unused buttons on the remote control or use the remote control from the device turned off at this time.
The schematic diagram of the remote control is shown in Figure 1. A special DA1 microcircuit amplifies and forms the electrical signal of the BL1 photodiode into electrical impulses. A comparator is built on radio elements DD1.1 and DD1.2, and a pulse generator is built on radio elements DD1.3, DD1.4.
The state of the control system (on or off the load) is controlled by the DD2.1 trigger. If the direct output of this trigger is log 1, the generator will operate at a frequency of approximately 1 kHz. Pulses will appear on the emitters of transistors VT1 and VT2, which through the capacitance C10 will go to the controlling output of the triac VS1. It will be unlocked at the beginning of every mains half cycle.
In the initial position, on pin 7 of the DA1 microcircuit, there is log 1, the capacitance C5 is charged through the resistances R1, R2 and at the input C of the DD2.1 trigger, log 0. If the IR signals from the remote control go to the BL1 photodiode, then on the contact 7 of the DA1 microcircuit there will be signals, and the capacitance C5 will be discharged through the diode VD1 and resistance R2.
When the potential at C5 drops to the lower level of the comparator (after 1 second or more), the comparator will switch and a signal will be sent to the DD2.1 trigger input. The trigger state of DD2.1 will change. This is how the devices switch from one state to another.
Microcircuits DD1 and DD2 can be used similar from the series K564, K176. VD2 is a zener diode for a voltage of 8-9 volts and a current of more than 35 mA. Diodes VD3 and VD4 - KD102B or similar. Oxide tanks - K50-35; C2, C4, C6, C7 - K10-17; C9, C10 - K73-16 or K73-17.
Setting up the IR remote control system
It consists in the selection of the resistance R2 of such a value that the switching occurs after 1 ... 2 s. If an increase in the value of this resistance leads to the fact that the capacitance C5 will not be discharged to the threshold voltage, it is necessary to double the capacitance C5 and re-adjust.
Capacitance C6 should be set in the event that the duration of the front of the pulse coming from the comparator to the trigger is excessively long and it will switch unstably.
If the used remote control does not allow you to control the device without interfering with the TV, it is possible to assemble a homemade remote control, which is a generator of rectangular signals with a repetition rate of 20 ... 40 kHz, functioning on an emitting IR diode. Options for a similar remote control on the KR1006VI1 timer (
The dimmer described below is designed for use with incandescent lamps. They control it using a remote control (RC) from any household equipment (TV, video player, etc.). The device can be useful for people with limited mobility or just people who value comfort. In addition, the regulator allows you to save energy through smarter and more justified use of lighting. Despite the fact that the idea of \u200b\u200busing a remote control to control lighting is clearly not new and many similar devices have been developed, it was not possible to find one suitable for repetition in the radio amateur literature and the Internet. As a result, a device was assembled, the diagram of which is shown in Fig. one.
The proposed dimmer is made on an available element base, it is well repeated (several copies were made) and assembled without errors in installation starts working immediately. A clear, confident, without failures and false spontaneous operation of the regulator is noted. The function of the switching element in it is performed by the KR1182PM1 phase power regulator microcircuit, which makes it possible to smoothly switch the light, protecting the lamp filament from premature burnout.
The regulator works as follows. When you press any button on the remote control, the emitted infrared signal is received by the B1 photodetector. At its output (pin 3), bursts of low voltage pulses appear, which, through the limiting resistor R1, enter the input of a one-shot, made on the DA1 microcircuit, and start it. At the output of DA1 (pin 3), a rectangular pulse of positive polarity is formed, the duration of which depends on the resistance of the resistor R3 and the capacity of the capacitor C2. The pulse arrives at the clock input (pin 14) of the counter-decoder DD1 and sets its output 1 (pin 2) high. Through the VD1 diode, it goes to pin 6 of the DA2 microcircuit, and the EL1 lamp lights up at full heat.
The next time you press the remote control button, the high level from output 1 of DD1 goes to output 2 (pin 4), and the voltage from the divider formed by resistors R4 and R8 is applied to pin 6 of DA2. The brightness of the lamp decreases. Further pressing the button leads to the fact that a high level appears sequentially at outputs 3, 4, 5 (respectively, pins 7, 10, 1), resistors R5, R6, R7 are turned on in the voltage divider supplied to pin 6 of DA2, and the brightness the lamp decreases even more. When a high level appears at output 6 (pin 5), which is connected to the R input (pin 15), the counter is set to zero, in which the voltage at all its outputs is low. The lamp goes out. Then everything is repeated.
The R2C1 circuit was introduced to improve the stability of the device. Diodes VD1-VD5 play the role of isolation. Elements VD6-VD10, R9, R10 and capacitors C4, C5 form a power source for the device. Integral stabilizer DA3 stabilizes the supply voltage of the photodetector B1.
The regulator is assembled on a printed circuit board (Fig. 2) from fiberglass foil on one side. All resistors and diodes are installed perpendicular to the board (the elements of the VD2R4-VD5R7, R9R10 circuits are soldered to the board with one pin, the latter are connected to each other). The B1 photodetector is installed above the DA1 timer case, for which its leads are bent at right angles. The board is connected to the mains and load through a connector block with screw terminals. The appearance of the mounted board is shown in Fig. 3.
A possible replacement for the KR1006VI1 microcircuit - 555 timers with various letter indices (NE, LM, etc.), the L78L05 integrated stabilizer - the domestic KR1157EN502A, etc. with an output voltage of 5 V. VD1-VD5 diodes - any low-power, VD6-VD9 -1N4004-1N4007 , KD209A, KD209V, etc. with a reverse voltage of at least 400 V. The KS191M Zener diode can be replaced with any low-power one with a stabilization voltage of 9 ... 10 V.
To control the regulator, the author uses the "Horizon" TV remote control. Photo detectors TSOP1133 and TSOP1733 were tested. The result is the same. In a room with an area of \u200b\u200b25 m 2, the board located on the table confidently received the reflected signal when the console was directed in different directions, even the furnishings located in the room did not interfere. When the board was covered with a sheet of paper, the sensitivity of the device dropped somewhat. And only after the photodetector was wrapped in a layer of black electrical tape, it began to receive only direct radiation from the remote control. But it turned out to be enough to use the regulator normally.
Other photodetectors can be used in the device, but for maximum reception range it is important that the carrier frequencies of the remote control and the photodetector are the same (for TSOP1133 - 33 kHz). I would also like to add that it is necessary to protect the photodetector from direct sunlight and bright light from electric lamps.
The board is installed in a decorative casing that covers the fixing of the chandelier to the ceiling. As practice has shown, the reflected infrared radiation from it is quite enough for switching. If the casing is close to the ceiling, one or two small holes must be drilled in it to allow the remote control radiation to enter. The standard lamp switch located on the wall must be turned on and will play the role of an auxiliary one.
If desired, by selecting resistors R4-R7, you can change the brightness of the lamp to your liking. As the resistance increases, the brightness decreases, and vice versa. The power of EL1 light bulb (or other load connected to the regulator) should not exceed 150 W. To increase it significantly, it is enough to connect a triac. By introducing an additional oxide capacitor with a capacity of 100 μF (with a nominal voltage of 16 V) in parallel with resistor R8 (plus to pin 6 of DA2), you can achieve smooth light switching, which can be more attractive.
The number of light levels can be increased or decreased. For example, if it is desirable to have six levels, its pin 6 should be connected to pin 15 of the DD1 microcircuit, and pin 5 through a diode and a 46 kΩ resistor should be connected to pin 6 of the DA2 chip. To obtain nine levels, pins 5, 6, 9, 11 of DD1 are connected to this DA2 pin (also through diodes and resistors), and pin 15 of the latter is connected to a common wire. Of course, for a smoother regulation with an increased number of levels, you will have to re-select the resistors of the circuits connecting the outputs of the DD1 microcircuit with pin 6 of DA2.
If there is no need to adjust the brightness, but it is enough just to turn on and off the lamp, the VD1-VD5 diodes and the R4-R7 resistors are removed, and the output 2 (pin 4) of the DD1 microcircuit is connected to its input R (pin 15). You can act differently (Fig. 4): replace the counter-decoder K561IE8 with one of the D-flip-flops of the K561TM2 microcircuit operating in counting mode, and the KR1182PM1R microcircuit with a VS1 triac connected through the U1 optocoupler (the numbering of the remaining elements continues as in Fig. 1).
In this case, the load power will be limited by the parameters of the triac (when using BTA16-600B -2 kW).
Obviously, the dimmer can be used not only to control lighting, but also to regulate the power of various electric heating devices (for example, heating elements), electric motors, etc., devices of appropriate power. The input part of the regulator can be used as a source of a control signal, equipping various devices with a simple remote control, for example, those that are difficult to access or they are at a considerable height (the signal is taken from pin 3 of DA1). For alternate control of two different loads, you can use the second trigger of the K561TM2 microcircuit (Fig. 5). The loads will be switched on in the sequence: load 1 on - load 2 on - both loads on - both loads off - load 1 on, etc.
In conclusion, it should be said that it would probably be more competent to adjust the brightness of the light from minimum to maximum. In this case, when turned on, the load on the KR1182PM1R microcircuit is less, the life of the electric lamps is extended and for vision there is a not so contrasting transition. The author just found it inconvenient. And you can change the direction of regulation by swapping the connection points of the anodes of the diodes VD1 with VD5 and VD2 with VD4.
And the last thing. All elements and circuits of the regulator are galvanically connected to the 220 V network, therefore, during testing, adjustment and during operation, the rules of electrical safety should be observed.
Literature
1. Zeldin E. Application of the integral timer KR1006VI1. - Radio, 1986, No. 9, p. 36, 37.
2. Dolgiy A. Modules of receivers of infrared signals. - Radio, 2005, No. 1, p. 47-50.
3. Nemich A. Chip KR1182PM1 - phase power regulator. - Radio, 1999, No. 7, p. 44-46.
Date of publication:23.11.2014
Readers' opinions
- Eugene / 02/25/2015 - 11:20
I beg your pardon, but is it possible to get a structural diagram for this dimmer?
