NOTE: A Vishay - TSOP4840 Ir Receiver Module was used to obtain the information for this page.
The diagram shows three outputs from the oscillator shown. Oscillator Outputs B and C are practical application signal for the TSOP4840 Ir Receiver Module.
OSCILLATOR OUTPUT - A - Continuous 40 kHz - The output of the IR receiver will go LOW when the detector sees this signal.
(The IR receiver will slowly go blind and its output will go HIGH if the received signal is continuous.)
OSCILLATOR OUTPUT - B - Pulsed 40 kHz - The output of the IR receiver will go LOW each time a 7 Hz burst of the 40 kHz signal is received.
(The duration of the receiver's output pulse is slightly shorter than the duration of the received 40 kHz signal.)
The oscillator B output is used in the Infrared - Proximity Detector Circuit located at this site.
OSCILLATOR OUTPUT - C - Pulsed 40 kHz modulated at 833 Hz - The output from the receiver produces a series of 833 Hz pulses at a rate of 7 Hz .
(The 833 Hz pulses represent the data that TV remote would be sending to the IR receiver.)
Before using this or a similar device, their data sheet should be read carefully and any power supply recommendations should be followed to prevent false output pulses.
The receiver module used for this test worked very well under all levels of incandescent lighting.
Under very bright or direct florescent lighting the output became unstable. Usually at distances of less than 1 meter from a 48 watt fixture.
Based on data sheet information, Oscillator Output - C most closely resembles the manufactures test conditions specified for the device.
When no infrared signal is being received there can be spurious output pulses. Typical remote control receiver circuits would no doubt be able to ignore these pulses.
The following diagram is for an oscillator that was used to get the information for Oscillator Output - C as shown above.
Infrared light is invisible to the naked eye, however, a digital camera can be used to view the IR light if it does not have an IR specific filter on the lens.
The image may not be very bright but close-up or in a darkened area the light should be visible on the cameras display screen.
The explanations for the circuits on these pages cannot hope to cover every situation on every layout. For this reason be prepared to do some experimenting to get the results you want. This is especially true of circuits such as the "Across Track Infrared Detection" circuits and any other circuit that relies on other than direct electronic inputs, such as switches.
If you use any of these circuit ideas, ask your parts supplier for a copy of the manufacturers data sheets for any components that you have not used before. These sheets contain a wealth of data and circuit design information that no electronic or print article could approach and will save time and perhaps damage to the components themselves. These data sheets can often be found on the web site of the device manufacturers.
Although the circuits are functional the pages are not meant to be full descriptions of each circuit but rather as guides for adapting them for use by others. If you have any questions or comments please send them to the email address on the Circuit Index page.
26 August, 2013