Hi Eugene1215,
Please see below comment for reference,
1, As the description from BME280 HSMI document, we don't recommend total and partial covering the sensor.
If you want to under fill the sensor with gel, should protect the air hole on the sensor surface and keep no gel into the sensor
The performance of the sensor will be influenced with under fill gel
2, Based on the HSMI chapter5.1
If you can use membrane to protect the sensor and pad
If your equipment structure available, you can reference the design from chapter5.1
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