Bosch Sensortec BMP280 vs BME280 Sensor Confusion - Printable Version

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RE: Bosch Sensortec BMP280 vs BME280 Sensor Confusion - AllyCat - 14-01-2019

Hi,

Thanks.  Yes that's exactly the seller I found on ebay.com (I guess the price is US$ not NZ$), but with free ("Economy") shipping.   

Cheers,  Alan.

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RE: Bosch Sensortec BMP280 vs BME280 Sensor Confusion - werk_ag - 14-01-2019

(14-01-2019, 02:38)AllyCat Wrote:  AFAIK the SHT3x humidity sensors are 2.4 - 5.5 volts tolerant so shouldn't need any level shifter? 

Yes, that is true, they are 5V tolerant, but those ones without the level shifter (the two FETs) can't be connected to the extended I2C bus on the TX interface.
Without a second I2C bus extender chip on the sensor side, they will work too, but not for so long. The reason is related to the current demanded by the I2C extended bus chip on the TX board, the SHT31 can only drive 5mA. The modules that have the two FETs, do an excellent job here as they isolate the SHT31 chip from the I2C extended bus.
Hope my poor English makes this understandable.

The info above comes from a research and experiments done by t3gathome

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RE: Bosch Sensortec BMP280 vs BME280 Sensor Confusion - JT118 - 14-01-2019

This link supplied a BME280;

https://www.ebay.co.uk/itm/192783393464?ViewItem=&item=192783393464

and I now have this Closed Cube SHT31 outside which comes complete with filtercap,

https://www.ebay.co.uk/itm/ClosedCube-SHT31-D-Mini-with-SF2-Filter-Cap-Breakout-Board/182974536376

These cheaper SHT31 seem to have rather more limited life though they are fine while they work;

https://www.ebay.co.uk/itm/New-SHT31-SHT31-D-Temperature-Humidity-Sensor-Breakout-Weather-For-Arduino-AS/291958217394?

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