Method for resisting sunlight interference by infrared receiver

2020-10-21 16:58:42 1443

     Many outdoor products also use infrared transmitter tubes and infrared receivers as the first choice for remote control or data transmission solutions. However, because the outdoor light is relatively sufficient, especially when the sun is clear, the infrared receiver often fails. After discussing with some customers, the basic solution is as follows

First understand the reasons for the failure of the infrared receiver:

    The components of infrared receivers generally include infrared receiving head (three-pin kind, as shown in the figure), infrared receiving tube (three-pin kind, also called photodiode or triode as shown in the figure), others are not The commonly used ones are not mentioned. There is a PD chip in these components, which plays the role of receiving infrared rays. The key is here, the function of infrared receiver is to receive infrared, so if there is a problem with this chip, then the infrared receiver will fail. And this PD can receive infrared rays with a wide range of wavelengths, so regardless of the infrared rays in the sun or the infrared rays emitted by the infrared emission tube, the PD can receive it. Therefore, when the sun is shining outdoors, the sun is always bright, and the infrared receiver will first receive the infrared rays in the sun, and the light sensitivity of the PD will reach a saturated state, so that it can no longer receive the infrared rays of the infrared emitter.

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Solution steps:

1. Use infrared receiver with strong anti-light interference ability, such as Taiwan Everlight: IRM56384.IRM3638

2. Use 940nm wavelength infrared transmitting tube, because the best receiving wavelength of infrared receiving head is 940nm;

3. Load the carrier frequency of 38KHZ on the transmitting end;

4. Increase the hood to avoid direct sunlight to the infrared receiver;

5. Add a filter to filter out excess light, and only allow light waves around 940nm to enter the infrared receiver.


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