Hi guy´s
Does anyone know how to connect these sensors (BME280,BME680) to the Dev. board?
Is it straight to SCL/SDA/Vext (if used) or is coupling or pull ups/downs needed for stability issues?
Also found a lot of discussions regarding turning on and off VEXT while in sleep mode to preserve power, but some issues where reported
/ BR
Andy
Hello willhelmx,
the boards i used need only VCC, GND, SCL and SDA.
Possible special applications needs additional cabling.
Greetings
E_T
Ok, wéll give it a go, sometimes ivé seen examples keeping some isolation between the connectors with resistors and sometimes not…
Do you know if the VEXT output for power off the BME still have issues?
BR
/A
vext is working without problems if you use it right.
Keep in mind when using a bme680 that after each powercycle the baseline is reset. This is leadung to gas readings thar are everytime the same.
You can find functions for storing and restoring the baseline for the bme680 in the LoRaWAN multisensor example
Here some Infos:
Hello WASN,
extract from LoRaWAN Multisensor example doesn’t solve the Problem with the value GAS:
BME680: T = 24.24C, RH = 48.30 %, Pressure = 1009.12 hPA, GAS = 8083.70mOhm, IAQ = 26.68
BME680: T = 24.24C, RH = 48.28 %, Pressure = 1009.14 hPA, GAS = 8083.70mOhm, IAQ = 26.69
BME680: T = 24.25C, RH = 48.37 %, Pressure = 1009.14 hPA, GAS = 8083.70mOhm, IAQ = 26.65
BME680: T = 24.24C, RH = 48.44 %, Pressure = 1009.12 hPA, GAS = 8083.70mOhm, IAQ = 26.62
BME680: T = 24.23C, RH = 48.40 %, Pressure = 1009.12 hPA, GAS = 8083.70mOhm, IAQ = 26.64
BME680: T = 24.22C, RH = 48.35 %, Pressure = 1009.14 hPA, GAS = 8083.70mOhm, IAQ = 26.66
BME680: T = 24.22C, RH = 48.32 %, Pressure = 1009.12 hPA, GAS = 8083.70mOhm, IAQ = 26.67
BME680: T = 24.21C, RH = 48.29 %, Pressure = 1009.12 hPA, GAS = 8083.70mOhm, IAQ = 26.68
BME680: T = 24.20C, RH = 48.26 %, Pressure = 1009.10 hPA, GAS = 8083.70mOhm, IAQ = 26.70
BME680: T = 24.20C, RH = 48.26 %, Pressure = 1009.10 hPA, GAS = 8083.70mOhm, IAQ = 26.70
BME680: T = 24.21C, RH = 48.26 %, Pressure = 1009.14 hPA, GAS = 8083.70mOhm, IAQ = 26.70
BME680: T = 24.23C, RH = 48.25 %, Pressure = 1009.16 hPA, GAS = 8083.70mOhm, IAQ = 26.70
BME680: T = 24.24C, RH = 48.22 %, Pressure = 1009.12 hPA, GAS = 8083.70mOhm, IAQ = 26.71
BME680: T = 24.23C, RH = 48.19 %, Pressure = 1009.14 hPA, GAS = 8083.70mOhm, IAQ = 26.73
BME680: T = 24.24C, RH = 48.16 %, Pressure = 1009.12 hPA, GAS = 8083.70mOhm, IAQ = 26.74
Which bme680 library are you using?
I will have a look tomorrow
Hi Both , for info I have had the exact same gas reading and thought the sensor was faulty, as such a low reading may be its a reading issue .I was using the blue dot library.
Simon
sorry for the confusion.
my head is a little overfilled these days.
the mentioned baseline is only relevant for an CCS811 and not for a bme680.
i will try to find time to dig into it.
The gas sensor isn’t as simple as Temp,Humidity, pressure etc. see notes
Please note this sensor, like all VOC/gas sensors, has variability and to get precise measurements you will want to calibrate it against known sources! That said, for general environmental sensors, it will give you a good idea of trends and comparisons. We recommend that you run this sensor for 48 hours when you first receive it to “burn it in”, and then 30 minutes in the desired mode every time the sensor is in use. This is because the sensitivity levels of the sensor will change during early use, and the resistance will slowly rise over time as the MOX warms up to its baseline reading.
The heated metal oxide changes resistance based on the volatile organic compounds (VOC) in the air, so it can be used to detect gasses & alcohols such as Ethanol, Alcohol and Carbon Monoxide, and perform air quality measurements. Note it will give you one resistance value, with overall VOC content, but it cannot differentiate gasses or alcohols.
iann, yes will underline this aswell, all gas sensors will require a continous power on for somewhat accurate readings, calibration is also neccesary for more accurate readings although a indication of rising levels easily can be obtained…
Br
/ A