BSEC + BME680 Timing Questions

[NickXML]

Mea culpa: I've managed to confuse myself regarding the different power modes offered by BSEC and the BME680. I've read a few different posts on here that seem similar to my question, but the answers don't seem to quite answer my specific use case.

So my apologies if this has been asked before and I didn't understand previous answers.

Here is what I would like to have happen:

A device with a BME680 is in sleep mode. Every X minutes, it wakes up and takes a reading of temperature, pressure, humidity, tVOC and tVOC accuracy. The device then goes back to sleep.

I would like X to be any one of 1, 3, 5 and 10 minutes. In other words, I want to create firmware for a device that allows me to select the duration of the sleep/wake cycle from a range of values. In some cases the device will take readings every minute, in other cases, it might take readings every 3, 5 or 10 minutes.

My questions:

1. My understanding is that if I use BSEC, the only choice for X is 5 minutes or 3 seconds. Is that correct? 

2. If that is incorrect (or partially correct), is there any feasible way to support the different timing intervals I'm looking for? e.g. would the BME680 effectively have to be in 3s mode and I would capture every 20th reading for a 1 minute interval, or every 40th reading for a 2 minute interval. 

All suggestions and comments are welcome. 

Thank you.

[BSTRobin]

Hello NickXML,

If you use BSEC, it supported 5 minutes or 3 seconds, haven't supported other time.

[NickXML]

Thanks for your reply. From what I have seen and read here, the BME680 is not very useful without BSEC since there is so much variation between sensors. 

How can other timings be achieved? Is there literally no possible solution with BSEC? Again, I need to capture temperature, pressure, humidty and tVOC.

Would any of these approaches work?

(a) For 1 minute timing, could we run the BME680 in 3s mode and throw away 19 out of 20 readings (every 20th reading would be at the one minute mark)? Or similarly, for 10 minute intervals, could we not just run in the 5 minute mode and throw away every other reading?

(b) Alternatively, could I not completely power down the BME680 and power it up some window of time before a reading e.g. power on in 3s mode, run for X seconds to gather a stable reading, power off completely for X minutes, repeat...

(c) Or is it possible to switch dynamically between 5 minute mode and 3 second mode? In this case we'd never fully power down the BME680, we'd just switch between power modes.

 Please let me know if any of the above options would work. If they won't work, please explain why not.

Thank you.

[NickXML]

Could I get a reply?

I understand that the BME680 will only run in 3s and 5m mode. From what I have seen and read here, the BME680 is not very useful without BSEC since there is so much variation between sensors. 

So what are the practical approaches to other timings that capture temperature, pressure, humidty and tVOC?

Would any of these approaches work?

(a) For 1 minute timing, could we run the BME680 in 3s mode and throw away 19 out of 20 readings (every 20th reading would be at the one minute mark)? Or similarly, for 10 minute intervals, could we not just run in the 5 minute mode and throw away every other reading?

(b) Alternatively, could I not completely power down the BME680 and power it up some window of time before a reading e.g. power on in 3s mode, run for X seconds to gather a stable reading, power off completely for X minutes, repeat...

(c) Or is it possible to switch dynamically between 5 minute mode and 3 second mode? In this case we'd never fully power down the BME680, we'd just switch between power modes.

I would appreciate some feedback. Will any of the above options work? If not, please explain why not.

Thank you.

[Minhwan · Accepted solution]

Hello NickXML, 

Technically, you can't change timing mode in running. Therefore, (c) is not available.

I'd like to recommend to (a) method in your case. 

Thank you.