Constant Gas reading

[ernesst]

I've acquired recently an Adafruit BME680, with a Pi Zero W.
During the first day the sensor was able to get a resistance reading for the gas, currently the reading is stuck to 45556 whatever atmosphere is. (I've tried alcohol & black marker)

I'm wondering if it's a bug or the sensor burnt.
As you can see below, the sensors jumped between stuck and reading and now it seems staying stuck.

The humidity and temperature reading give a relevant feedback.
I'm not recalling specific intervention from me able to act on the resistance reading.

Thanks

[ernesst]

Without touching anything the reading went back then collapse for an hours

I'll let it run.

[caternuson]

As a comparison check, I ran an UNO with the Arduino lib. I logged data for ~1 hour, breathing on it at the beginning and end to generate a response. Plot of millis() vs. gas_resistance:

There's a general warming up trend, but it otherwise responded to breath.

I also did a similar check with an Itsy Bitsy M4 and CP 3.1.1. I seemed to have gotten the same odd behavior. Plot of time.monotonic() vs. gas:

It initially responded, but then the reading froze. Other readings, like temperature and humidity were still responding.

[kattni]

@caternuson Can you test this again? I believe it may have been resolved by #18 based on reference to #12.

[caternuson]

@kattni Yep, appears to be fixed. Or at least could not repeat the same behavior as above. Here's latest test result for plot of gas:

import time
import board
import digitalio
import adafruit_bme680

bme = adafruit_bme680.Adafruit_BME680_I2C(board.I2C())

led = digitalio.DigitalInOut(board.D13)
led.direction = digitalio.Direction.OUTPUT
led.value = False

go = digitalio.DigitalInOut(board.D10)
go.direction = digitalio.Direction.INPUT

print("logging...")
with open("/data.csv", "a") as fp:
    while go.value:
        fp.write("{},{},{},{},{}\n".format(time.monotonic(),
                                           bme.temperature,
                                           bme.gas,
                                           bme.humidity,
                                           bme.pressure))
        fp.flush()
        led.value = not led.value
        time.sleep(1)
print("DONE.")

[kattni]

Resolved. Closing.