How specific is Pololu IR Proximity Sensor to 38 kHz

I’ve been excited since learning about this Proximity sensor. I have gone down many blind allies for use in the Arizona sun and weather. In the published schematic, I see the 38kHz strobing of the IR emitter, but I have searched datasheets, etc. for the TSSP77 IR detector, but did not find any selectivity to any strobe frequency. For example, the VS1838 IR receiver has filtering for 38kHz. My application can’t afford ambient or spurious triggering. Please explain. *


I recommend looking at Figure 5 in the TSSP77038 datasheet (page 3), which you can find on the product page under the “Resources” tab). In our experience, these types of sensors usually tend to be somewhat sensitive to nearby frequencies, for example a 38 kHz sensor will still respond to a 56 kHz modulated signal if the emitter is very close.

- Patrick

[quote=“PatrickM, post:2, topic:25556”]
TSSP77038 datasheet
Thank you Patrick. I missed that. It appears to be about as frequency selective as the VS1838. Initially I wasn’t sure if Fig. 5 referred to the strobe frequency or the frequency of the received “color” (i.e. c/lambda), but Fig. 7 on Pg. 4 clearly is about wavelength (lambda).

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