BME688 Life

[Keno48]

What is the expected life of the BME688 CO gas sensing capability?  CO detectors usually have a limited life, eg 5-10yrs. What is the expected life for interior, residential use in a thermostat?  

[BSTRobin]

Hi Keno48,

Thank for your inquiry.
A usual assumption is for instance is that if accelerated stress tests like HTOL and THB are passed over 1000 hours, that this corresponds to the load of 10 years in the field. However, if a 1000 hour THB corresponds to 10 years stress or more/less is something which the user has to derive from his application conditions (“mission profile”).

[Keno48]

I'm not familiar with those stress tests, but the REAL question is the EOL of the sensor itself.  The electrochemical-based CO sensors ONLY last for 5-8yrs due to sensor deterioration; from the NIST site, quoting "All sensors have a limited lifetime, which will vary between manufactures" (and they site the metal oxide as well as the electrochemical sensors immediately b4 this statement)[How Do Carbon Monoxide Detectors Work? | NIST].   So, what is the expected life of these sensors?--take the best case scenario, viz used in a residential environment in a temp controlled room (heated, cooled as needed thru the seasons): what is the EOL expectation?  In an environment that is relatively clean for IAQ for years, with ideal, controlled power supply to the BME688, I would like to know the EOL for example, in use to detect, for example, the potentially toxic level of CO.  Common residential CO detectors are electrochemical and they have an EOL of 5-8yrs.  What is the equivalent for my proposed case with the BME688? Or are u suggesting that it would also be related to the requested sampling frequency of the master device?  - If so, what are the failure modes for these metal oxide sensors?  Thx