What could be wrong? Bad values displayed (BME280)

darekhome · July 14, 2024, 6:17pm

I have noticed that BME280 sensor is measuring/showing wrong values - see picture example - temp. -143,9 °C… Other values (humidity, preasure) I think are wrong too…
I have replaced the sensor - to new BME 280, but nothing changed - still the same…
Voltage 3,3V is O.K.

Any idea what could be wrong?

Looking on debug mode - only info about PMS sensor is mentioned… Nothing about BME…

validate request auth…
ws: debug level …
R/ PMSx003
/R PMSx003
output values to display…
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
output values to display…
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
output values to display…
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
output values to display…
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
output values to display…
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
output values to display…
ws: data json…
R/ PMSx003
/R PMSx003
ws: data json…
ws: data json…
ws: data json…
ws: data json…
ws: data json…
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
output values to display…
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
output values to display…
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
output values to display…
R/ PMSx003
0 - 66 - 42 - 66 .
1 - 77 - 4d - 77 .
2 - 0 - 0 - 0 .
3 - 4 - 4 - 4 .
4 - 228 - e4 - 228 .
5 - 0 - 0 - 0 .
6 - 1 - 1 - 1 .
7 - 119 - 77 - 119 .
Checksum is: 375
Checksum should: 0
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
/R PMSx003
R/ PMSx003
0 - 66 - 42 - 66 .
1 - 77 - 4d - 77 .
2 - 0 - 0 - 0 .
3 - 28 - 1c - 28 .
4 - 0 - 0 - 0 .
5 - 3 - 3 - 3 .
6 - 0 - 0 - 0 .
7 - 3 - 3 - 3 .
8 - 0 - 0 - 0 .
9 - 3 - 3 - 3 .
10 - 0 - 0 - 0 .
11 - 3 - 3 - 3 .
12 - 0 - 0 - 0 .
13 - 3 - 3 - 3 .
14 - 0 - 0 - 0 .
15 - 3 - 3 - 3 .
16R/ PMSx003
/R PMSx003
output values to display…
R/ PMSx003
0 - 66 - 42 - 66 .
1 - 77 - 4d - 77 .
2 - 0 - 0 - 0 .
3 - 28 - 1c - 28 .
4 - 0 - 0 - 0 .
5 - 4 - 4 - 4 .
6 - 0 - 0 - 0 .
7 - 4 - 4 - 4 .
8 - 0 - 0 - 0 .
9 - 4 - 4 - 4 .
10 - 0 - 0 - 0 .
R/ PMSx003
0 - 66 - 42 - 66 .
1 - 77 - 4d - 77 .
2 - 0 - 0 - 0 .
3 - 28 - 1c - 28 .
4 - 0 - 0 - 0 .
5 - 5 - 5 - 5 .
6 - 0 - 0 - 0 .
7 - 6 - 6 - 6 .
8 - 0 - 0 - 0 .
9 - 6 - 6 - 6 .
10 - 0 - 0 - 0 .
11 - 5 - 5 - 5 .
12 - 0 - 0 - 0 .
13 - 6 - 6 - 6 .R/ PMSx003
0 - 66 - 42 - 66 .
1 - 77 - 4d - 77 .
2 - 0 - 0 - 0 .
3 - 28 - 1c - 28 .
4 - 0 - 0 - 0 .
5 - 4 - 4 - 4 .
6 - 0 - 0 - 0 .
7 - 5 - 5 - 5 .
8 - 0 - 0 - 0 .
9 - 6 - 6 - 6 .
10 - 0 - 0 - 0 .
11 - 4 - 4 - 4 .
12 - 0 - 0 - 0 .
13 - 5 - 5 - 5 .
R/ PMSx003
0 - 66 - 42 - 66 .
1 - 77 - 4d - 77 .
2 - 0 - 0 - 0 .
3 - 28 - 1c - 28 .
4 - 0 - 0 - 0 .
5 - 4 - 4 - 4 .
6 - 0 - 0 - 0 .
7 - 5 - 5 - 5 .
8 - 0 - 0 - 0 .
9 - 5 - 5 - 5 .
10 - 0 - 0 - 0 .
11 - 4 - 4 - 4 .
12 - 0 - 0 - 0 .
13 - 5 - 5 - 5 .R/ PMSx003
0 - 66 - 42 - 66 .
1 - 77 - 4d - 77 .
2 - 0 - 0 - 0 .
3 - 28 - 1c - 28 .
4 - 0 - 0 - 0 .
5 - 4 - 4 - 4 .
6 - 0 - 0 - 0 .
7 - 4 - 4 - 4 .
8 - 0 - 0 - 0 .
9 - 4 - 4 - 4 .
10 - 0 - 0 - 0 .
11 - 4 - 4 - 4 .
12 - 0 - 0 - 0 .
13 - 4 - 4 - 4 .

Blockquote

Juggler · July 16, 2024, 12:58pm

Have a look at what the Tasmota page says about this sensor under Note what is recommended with the CSB and SD0 pin.

I also put the BME280 in smaller housings with only very small openings. This reduces problems with condensation and also the interplay between condensation and frost. This smoothes out the sensor values without the sudden deflections, but you still have values where otherwise the sensor would only deliver garbage.

fredvduin · July 18, 2024, 11:36am

Have you solved your problem?

darekhome · July 18, 2024, 12:44pm

Hi… Unfortunatelly I had no time to look deeper…
Plan to do somwhere in August…

fredvduin · July 19, 2024, 9:43am

For August.

How is the backside of the PCB?
Try another adapter (spikes on voltage)

It looks like you have a IIC problem (cable/bus), remove all IIC devices except BME280 and check again.
Can you check the resistance SDA and SCL between PCB and BME280 (SDA PCB <=>SDA BME 280 and SCL<=>SCL)
Voltage BME280 3.3V was ok?

Thin cable and crown stone is not the best way to connect cables (my experience)

Can you make a new IIC cable and if possible without connectors and crown stone

Herve5 · July 19, 2024, 6:31pm

I had a similar experience with an old, recuperated device. It seemed that rebooting the thing would occasionally solve it.
I deduced that was a matter of a wrong internal cabling. I dismounted the cable both sides then remounted it carefully. The… second time I did that solved it…