About Johanan

Johanan · ‎01-16-2020

It is true that this was a test project, which I wanted to see if it can be done. Unfortunately the BMP388 pin out is different, but I will be happy to edit the pcb. Do you think the 388 can do a much better job in such application? Thanks.

Johanan · ‎01-16-2020

Well, you are correct that I am starching it, but I am still within the data sheet specifications. according to my settings, in ultra high resolution, and IIR cof. I set, the nois in pressur measurment shuld be 0.2 pa. I avarge this more by my own IIR, and still get fluctuations 3 pa, and slow drifts of 6 - 8 pa in a short time. So I wonder if the data sheet is inaccurate, or I am doing something wrong, or I misunderstand the data sheet. Price of differential sensors for this range is much higher then BMP280 or BMP388.

Johanan · ‎01-15-2020

Hello, I am trying to measure the pressure inside a box (about 1x1x1 meters), which has a few fans taking air out. The measured range is 10 to 50 pa. I use 2 BMP280 devices, one outside the box, one inside the box. I calibrate the difference when no fan is on, I get 0 pa. Whoever after some time, there is a drift, which I cant explain. I read the data sheet many times, and it seems that I should be able to get an accurate measurement, but I have seen drifts of 30 pa difference with no fan working on a stable system. I am using "Ultra high resolution" prs oversampling x16, Temp. Over sampling x2, IIR coefficient x16, and I even add my own IIR of x32 is my software. Sample delay is 0.5ms , as power consumption is not an issue. Stile, I have this drift. What am I missing? Is there some particular PCB layout needed (I followed all recommendations on data sheet, my PCB has only 3 mounting holes and so on. Thanks Johanan

Bosch Shared

About Johanan

Re: BM280 stability

Re: BM280 stability

BM280 stability

About Johanan

Re: BM280 stability

Re: BM280 stability

BM280 stability

Still looking for something?