Infrared transducers

A number of wireless devices transmit and receive energy at the infrared (IR) wavelengths, instead of at radio wavelengths. Infrared energy has a frequency higher than that of radio waves, but lowers than that of visible light. Infrared is at times called as heat radiation, but this is a misnomer. Some wireless devices transmit and receive their signals in visible-light range, although these are encountered less than IR devices.

The most common IR transmitting transducer is infrared-emitting diode (IRED). A fluctuating dc is applied to the IRED. The current causes device to emit IR rays; the fluctuations in current constitute modulation, and produce rapid variations in the intensity  of rays emitted by semiconductor junction. The modulation has information, such as which channel your television set should look for, or whether the volume is to be raised/ lowered. Infrared energy is not visible, but at some wavelengths it is focused by ordinary optical lenses and reflected by the ordinary optical mirrors. This makes it possible to collimate IR rays so they can be transmitted for distances up to hundred feet.

The only real difference is that diodes are maximally sensitive in IR, instead of in the visible, part of electromagnetic spectrum. The fluctuating IR energy from transmitter strikes P/N junction of receiving diode. If receiving device is a photodiode, a current can be applied to it, and this current varies rapidly in according to the signal waveform on IR beam from transmitter. If receiving device is a photovoltaic cell, it generates- the fluctuating current by itself, without the requirement of an external power supply. In either of the case, the current fluctuations are weak, and should be amplified before they are delivered to equipment (television set, oven, security system, garage door, etc.) is controlled by wireless system.

Infrared wireless devices work best on the line of sight, which is, when the transmitting and receiving transducers are located so that rays can travel without encountering any obstructions.  You may have probably noticed this when by using television remote control boxes, most of which work at IR wavelengths. Sometimes enough energy will bounce off walls or ceiling of a room to let you change the channel when remote box is not on a direct line of sight with television set. But best range can be obtained by making sure you and the television set can see each other. You can’t put an IR control box in your pants pocket and expect it to work. Radio and IR control boxes are mistaken for one another because they look alike to casual observer.

A number of wireless devices transmit and receive energy at the infrared (IR) wavelengths, instead of at radio wavelengths. Infrared energy has a frequency higher than that of radio waves, but lowers than that of visible light. Infrared is at times called as heat radiation, but this is a misnomer. Some wireless devices transmit and receive their signals in visible-light range, although these are encountered less than IR devices.

The most common IR transmitting transducer is infrared-emitting diode (IRED). A fluctuating dc is applied to the IRED. The current causes device to emit IR rays; the fluctuations in current constitute modulation, and produce rapid variations in the intensity  of rays emitted by semiconductor junction. The modulation has information, such as which channel your television set should look for, or whether the volume is to be raised/ lowered. Infrared energy is not visible, but at some wavelengths it is focused by ordinary optical lenses and reflected by the ordinary optical mirrors. This makes it possible to collimate IR rays so they can be transmitted for distances up to hundred feet.

The only real difference is that diodes are maximally sensitive in IR, instead of in the visible, part of electromagnetic spectrum. The fluctuating IR energy from transmitter strikes P/N junction of receiving diode. If receiving device is a photodiode, a current can be applied to it, and this current varies rapidly in according to the signal waveform on IR beam from transmitter. If receiving device is a photovoltaic cell, it generates- the fluctuating current by itself, without the requirement of an external power supply. In either of the case, the current fluctuations are weak, and should be amplified before they are delivered to equipment (television set, oven, security system, garage door, etc.) is controlled by wireless system.

Infrared wireless devices work best on the line of sight, which is, when the transmitting and receiving transducers are located so that rays can travel without encountering any obstructions.  You may have probably noticed this when by using television remote control boxes, most of which work at IR wavelengths. Sometimes enough energy will bounce off walls or ceiling of a room to let you change the channel when remote box is not on a direct line of sight with television set. But best range can be obtained by making sure you and the television set can see each other. You can’t put an IR control box in your pants pocket and expect it to work. Radio and IR control boxes are mistaken for one another because they look alike to casual observer.