I see many posts reporting what seems to be different BME280 readings using different drivers. In addition there are many discussions regarding the efficacy of using an 8-bit processor when making complex calculations. So I decided to compare the CALCULATIONs between a ProMini and a program providing additional computational capability. In this case Excel (2019).
Remember this is only a comparison of the compensation calculations, not the accuracy of the device.
For this test I only compared the temperature calculatons.
Goal:
The goal of this experiment is to see how much accuracy is affected by the limitations of the 8-bit Pro Mini and
the Arduino IDE compiler.
The approach is to compare the Bosch equations evaluated on the Pro Mini with the same calculations in Excel.
We've read the Pro mini/IDE/CCV has a maximum resolution of 6 or 7 significant digits, while Excel has 15
Hardware:
For identification this BME280 (GY-BME board) is marked black on the edge where the wires are soldered.
Software:
We used the Blue Dot BME280 Driver to collect the required coefficients and raw & compensated Temp, Pressure and Humidity.
Excel 2019 using Bosch equations defined in their datasheet V1.6
Procedure:
- Connect board through FTDI programmer to Laptop.
- Download software and read parameters using the IDE monitor.
- Collect:
Sensor Coefficients
Uncompensated Temperature, Pressure & Humidity
Compensated Temperature, Pressure & Humidity
Conclusion
For this sensor at ~20 °C the difference between the Pro Mini calculations and the Excel Calculations is trivial and is well within the stated device accuracy.
Results / Data:
