si7021 sensor issues

We are having a near 40% attrition rate on units that are using this sensor board. After instillation the board is not readable by our system. Are there any reasons why the sensor is not detectable. Out of 20 units, 9 are defective. Also is it recommended to remove the white cover on the sensor at all? Thanks for your help.

Hello khartwilco, and thanks for posting.

We pretty much never have any trouble reports with this sensor. What voltage are you using for power and are they on a I2C bus with 5 volt components? The white cover is part of the sensor and shouldn’t be removed. Has the cover been removed from the units you’re having trouble with?

Thank you for the response. We have not removed the white covers. Is it safe to add silicone rubber coating to the board / around the sensor? Currently we are powering them via Raspberry Pi 3 model B.

You will probably want to fully cure the silicone before adding the sensors. Vapors from the silicone before cured could be causing damage to the sensor.

A Pi is fine as long as you’re using the 3.3 volt rail for powering the sensor. If you’re using 5 volt parts on the same I2C bus as the Si7021 and any of those devices has pullup resistors to the 5 volt line, that could also damage the sensor.

Do you happen to have a batch number off your sensors or your order/invoice number handy?