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IR remote Extender

2017-08-16 00:37  
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This article describes an infrared remote control Extender & # 8211; variant of a principle of explanation. In order to better grasp the principle of combining text, please understand this schematic. IR remote control Wavelength 850 - 950 nm between. In this short wavelengths, the light is not visible to the human eye, but the domestic camera can actually think this part of the electromagnetic spectrum. By a video camera, an infrared LED seem to change brightness. All remote control using a coded series of pulses, of which there are thousands of combinations. Light output intensity with each remote control, remote control, operates in 4.5 v dc usually provides a more powerful light output ratio 3 v DC control. Meanwhile, with the photodiode in this project has a peak light response in 850 sea miles, it receives a strong signal control operations? Close down, okay? This wavelength. The real response to photodiode infrared wavelengths from 400 nm to 1100 nm, so that all remote controls should be compatible.
Figure: The receiver is built on a silicon photodiode, available from Maplin SFH2030, CY90X script. The photodiode is very sensitive, it will respond to a wide spectral range of the infrared frequencies. A small amount of infrared in direct sunlight, so make sure the diode will not receive direct sunlight. If this happens, LED1 will be lit. There is a version of the SFH2030 a daylight filter built in, CY91Y  SFH2030F  script. A TIL100 will also get a good result here. A photodiode generates a minute when exposed to infrared radiation in the pulse current. This current (about 1 ua with SFH2030 and a typical infrared controlled using the distance of 1 meter) is amplified by the CA3140 opamp. The opamp configured as a current to voltage converter to produce an output of about 4.7 volts / uA input current. Photodiodes, can be placed about one meter away circuits. Shielded cable is not necessary, since the common mode signals (noise) will be rejected. It is necessary to use a MOSFET input type here is the zero output offset and input bias current is negligible. A 741 or LF351 can not be used for this circuit. The output is amplified by the BC337 opamp operating in common emitter mode. As a MOSFET opamp IC use, the static voltage output is zero, this transistor and two LED's will be lit. 1 k resistor ensures BC337 will be completely saturated, while limiting the base current to a safe level. Operating an infrared remote control and pointing at the photodiode (SFH2030) will cause the two LED is lit, you will only see the visual color LED (LED1) which will flicker. The principle is very practical, you can Duokanjibian better grasp this principle again.

IR Extender  Circuit

 

CA3140

In Use
The reception range of the IR remote control to the photodiode depends on the strength of the remote control, but I had a working range of a meter or so, this needs bearing in mind when placing the circuit. Its also a good idea to wire LED1, the coloured LED near to the photodiode, that way, you know that the unit has received a signal. The IR emitter has a larger range, I had no problems at 5 meters but may possibly work further distances. The emitting diodes are quite directional, so make sure it is aimed directly at the appliance to be controlled. The IR emitting diode is small and can be placed out of sight. I drilled a small hole above the door frame. The emitter diode leads were insulated and pushed through this hole, leaving an inch or so to adjust the angle and position of the LED. From a distance, the clear plastic lens of the diode could not be seen.

PCB Template
This has been very kindly drafted by Domenico from Italy. First the copper side:

pcb copper

A magnified view from the component side is shown below. Unfortunately the transistor outline was reversed in the original diagram, my thanks go to Federico Laura for correcting this diagram :

component side

Mark 1A Version
The 22n capacitor has a high impedance at 50/60Hz and daylight but allows a modulated signal to pass. The 2N2222 transistor is biased on under no signal, the BC337 will be fully off. A control signal will switch off and on the 2N2222 transistor at the modulation frequency of the control, which in turn controls the BC337. As this is a cleaner signal, the series resistor may be increased to 100ohms.

VN:F [1.6.9_936]

 


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