kriswiner/CMWX1ZZABZ

LongCricket BME280 odd data

patmolloy opened this issue · 31 comments

patmolloy commented

This is up and running successfully, but I am getting possibly wrong data from the BME280. I have the device transmitting every minute for now. The values a) look wrong and b) don't seem to change much/at all over time. GPS looks good. The analog port is returning a value close to 0.00 .. is that right or should it be the battery voltage? I've attached a data dump for the last hr from cayenne .. worth saying that the data from TTN is the data ending up in Cayenne .. last transmission 2 mins ago ..

{
"analog_in_4": 0.02,
"barometric_pressure_3": 1013.3,
"gps_5": "map[altitude:35.51 latitude:51.4571 longitude:-0.2192]",
"relative_humidity_2": 65,
"temperature_1": 18.8
}

The device is in free air, not enclosed.

At the moment external temp is circa 13.5 degC, humidity at 92% (rainy).

Overnight the device was reporting 20 degC all night - i.e. incorrect and not changing.

Any pointers please? Thanks!

9915c234-d25d-4801-8af3-39225d9adfbc.xlsx

You can get at the live data via Cayenne here https://cayenne.mydevices.com/shared/5d060b3489fa9c4e9001cf87

kriswiner commented
patmolloy commented

Hi Kris,

I am just using your github sketch -- the one you referenced. Just changed the TTN stuff, and the freq to EU868 Nothing else at all. I'll reload it all again to make sure I did not screw anything up. Was not aware of the FET on pin 2 requirement but looking at the sketch I do see

#define VbatCtl 2 // enable for battery voltage monitor

So that looks right?

Pat

kriswiner commented
patmolloy commented

Kris, I re-downloaded, made the change for TTN and freq and re-compiled .. same as before as far as I can tell ..

If I am on USB Power, VBAT (as transmitted to TTN) should be approx zero?

Even though out of the box the sketch is transmitting every 1 minute, is the sampling of the sensors on some different timing? I've not looked in detail at the sketch yet (and most likely my coding skills are not up to it anyway!!)

Thanks for the support, as ever :)

This is the serial monitor output at startup ..

Serial enabled!ID bytes: C2 28 17
Winbond  W25Q80BLUX1G   Chip ID = 0xEF, 0x40, 0x14, 0x0
Macronix MX25L12835FZNI Chip ID = 0xC2, 0x20, 0x18, 0xC2
Macronix MX25R6435FZAI  Chip ID = 0xC2, 0x28, 0x17, 0xC2
Spansion S25FL127S      Chip ID = 0x01, 0x20, 0x18, 0x4D
 
VDDA = 3.30 V
VBAT = 0.17 V
USB Connected!
STM32L0 MCU Temperature = 26.23
 
BMA400 accelerometer...
BMA400 I AM 90 I should be 90
 
BME280 I AM 60 I should be 60
 
BMA400 + BME280 are online...
 
x-axis self test = 2412.1mg, should be > 2000 mg
y-axis self test = 2085.9mg, should be > 1800 mg
z-axis self test = 859.4mg, should be > 800 mg
hold flat and motionless for bias calibration
x-axis offset = -134.7 mg
y-axis offset = 100.2 mg
z-axis offset = 47.3 mg
Calibration coefficients:
_dig_T1 =28083
_dig_T2 =26675
_dig_T3 =50
_dig_P1 =39085
_dig_P2 =-10673
_dig_P3 =3024
_dig_P4 =9073
_dig_P5 =-223
_dig_P6 =-7
_dig_P7 =12300
_dig_P8 =-12000
_dig_P9 =5000
_dig_H1 =0
_dig_H2 =373
_dig_H3 =0
_dig_H4 =292
_dig_H5 =50
_dig_H6 =30
LOCATION: NONE
SATELLITES: 2
      G3: SNR=19, ELEVATION=0, AZIMUTH=0, ACQUIRED
      G4: SNR=20, ELEVATION=0, AZIMUTH=0, ACQUIRED
VBAT = 0.04 V
BME280:
Altimeter temperature = 24.99 C
Altimeter temperature = 76.98 F
Altimeter pressure = 1014.66 mbar
Altitude = -38.56 feet
Altimeter humidity = 45.0 %RH
kriswiner commented
patmolloy commented

No, no battery at present. Just on USB. The issue I was/am seeing with the BME280 is that overnight it reported temp and humidity values that were wrong, and which did not change. That could be because of a very slow sampling rate .. for example, right now it is showing ..

{
  "analog_in_4": 0.03,
  "barometric_pressure_3": 1014.8,
  "gps_5": "map[altitude:35.26 latitude:51.457 longitude:-0.2193]",
  "relative_humidity_2": 44,
  "temperature_1": 25

}

The actual temp is 18.2C and humidity 74%

kriswiner commented
patmolloy commented

Thanks. I guess this remains a mystery then .. the values do not change when the device moves inside vs. outside and the outside value is incorrect (and unchanging). Could this be related to the device being on USB power? Or a faulty BME280? Bit stuck.

kriswiner commented
kriswiner commented
patmolloy commented

Hi Kris, I am just running off USB power at the moment. No battery tried so far.

I am definitely getting data back to TTN and Cayenne every minute. Including data from the BME280. But the BME data is just wrong. It's outside right now and I know what values I should be getting, but am not getting them. Moreover, over time they just do not change. Even if I bring the device inside, the values do not change. 12 hours last night it reported 20C and did not change. I got the value 20 every minute for 12 hours straight.

I don't think I have screwed anything up, and clearly the BME280 is working to a degree (no hardware error) , but somewhere the values it is returning are messed up.

The only thing I can think of is that it must be faulty somehow?? But it seems mighty unlikely.

I want to persevere with it really .. happy to return if faulty and pay for shipping back of a replacement.

patmolloy commented

Last 3 packets in the TTN console .. GPS changed a tiny bit. BME280 values rock solid but Temp and Humid wrong .. It's 18.2C and 73% right now (two different sources agree).

image

kriswiner commented
patmolloy commented

Chris, here is the .ino (just saved as .txt). It is literally your example with only the following lines altered ..

const char *appEui = "70B3D57ED001DDB7";
const char *appKey = "ACF8ADB08F84ED97777A8973B5385173";
const char *devEui = "567890ABCDEF0102";

LoRaWAN.begin(EU868);
LoRaWAN.setADR(true);
LoRaWAN.setSubBand(2); // 1 for MTCAP, 2 for TT gateways

The serial debug monitor does not output data for the BME280 except at startup ...

AssetTracker_longCricket.txt

patmolloy commented

Here is the SerialMonitor output on boot ...
SerialMonitor.txt

kriswiner commented
patmolloy commented

Don't see it .. there is a lot of GPS chatter, but I cannot see anything else after the initial report.

kriswiner commented
patmolloy commented

Ok, will do. Searching thru I did actually find one instance .. buried in a lot of GPS logging ..

LOCATION: 3D 2019/6/16 18:09:05.000 17D LLA=51.4572334,-0.2193177,34.605 EPE=6.879,6.225 SATELLITES=6 DOP=2.80,2.80

SATELLITES: 12
      G1: SNR=25, ELEVATION=83, AZIMUTH=325, EPHEMERIS, ACQUIRED, LOCKED, NAVIGATING
      G3: SNR=42, ELEVATION=50, AZIMUTH=227, ALMANAC, EPHEMERIS, ACQUIRED, LOCKED, NAVIGATING
      G4: SNR=0, ELEVATION=0, AZIMUTH=0
      G8: SNR=37, ELEVATION=30, AZIMUTH=165, EPHEMERIS, ACQUIRED, LOCKED, NAVIGATING
     G11: SNR=33, ELEVATION=78, AZIMUTH=162, EPHEMERIS, ACQUIRED, LOCKED, NAVIGATING
     G22: SNR=35, ELEVATION=73, AZIMUTH=215, EPHEMERIS, ACQUIRED, LOCKED, NAVIGATING
     G28: SNR=33, ELEVATION=28, AZIMUTH=275, EPHEMERIS, ACQUIRED, LOCKED, NAVIGATING
     G32: SNR=23, ELEVATION=0, AZIMUTH=0, ACQUIRED
    S120: SNR=0, ELEVATION=29, AZIMUTH=199
    S123: SNR=37, ELEVATION=24, AZIMUTH=142, ACQUIRED, LOCKED
    S136: SNR=0, ELEVATION=31, AZIMUTH=173
    R???: SNR=35, ELEVATION=0, AZIMUTH=0, ACQUIRED
VBAT = 0.03 V
BME280:
Altimeter temperature = 19.62 C
Altimeter temperature = 67.32 F
Altimeter pressure = 1015.10 mbar
Altitude = -50.46 feet
Altimeter humidity = 51.9 %RH
 
RTC:
RTC Time = 18:09:05.627 
RTC Date = 19:6:47

LOCATION: 3D 2019/6/16 18:09:06.000 17D LLA=51.4572334,-0.2193200,34.455 EPE=6.816,6.197 SATELLITES=6 DOP=2.80,2.80
kriswiner commented
patmolloy commented

Kris, here is what happened after that change .. The BME280 values look a lot more sensible (and are wobbling about a bit, which I would expect)

Shortly after the "GNSS go to sleep!" toward the end of the dump, the logging stopped (after the line "R???: SNR=36, ELEVATION=0, AZIMUTH=0, ACQUIRED, LOCKED"

SerialMonitor2.txt

kriswiner commented
patmolloy commented

BTW The logging did start up again, but contained only GPS stuff .. nothing else ...

Am using https://github.com/GrumpyOldPizza/ArduinoCore-stm32l0

patmolloy commented

Ardunio config ..

image

patmolloy commented

Kris, I have to do some prep work for a project tomorrow (it's heading for 8pm here). WIll be back online later .. thanks for all the help and sorry for any trouble!

kriswiner commented
kriswiner commented
kriswiner commented
patmolloy commented

Kris, I didn't have it .. but do now. I had manually created the folder/contents in arduino/hardware before ..

Just re-compiling ...

patmolloy commented

Voila ! It works :)

image