STHS34PF80 - cover glass

[rfi]

Hi,

we are working on integrating this sensor to our device. We would like to make it work as human detection in front of our device. I am testing this sensor using "STEVAL-MKI231KA" board without lens connected to our development board via I2C and I have problem to make it properly work with cover glass. I have tested thin and also thick transparent cover glass (1mm and 4mm) and the sensor's behavior is the same in both cases. Presence data from the sensor are not changing when human steps in front of the sensor even when the human is very close to the sensor.

Behavior without cover glass is as expected. It detects human in far and close distances without any problem.

Can you please advise me how to solve this? Does the sensor support some sort of calibration with cover glass?

[SLERO.1]

Hi,

I'm also waiting reply from ST about this issue.

thx 

[Federica Bossi]

Hi @rfi ,

As reported in the datasheet, STHS34PF80 operates with IR radiation (wavelength between 5 and 20 um). Therefore, you need to use a glass that is "transparent" in this range.
If the glass as some sort of attenuation for IR radiation, you need to lower the threshold for presence presence.

 

Additionally, if you are using the compensated data, you need to calibrate the optical system as described in the AN5867 in chapter 4.5.1.