BME280 sensor.

[richard]

henrik
i made a little change

used this style
IF P2.15 = 1 THEN
p2.highWORD = 65535
ENDIF

for all the casts to long , it saves a worthwhile bit of code space

can't test humidity on pic yet , just discovered the dishonest ebayer has sold me 4 out of 5 bmp280's in lieu of bme280 boards.
i can't tell them apart with naked eye, must admit the temp seems more accurate in absolute terms for the bmp boards there is nearly a 3 deg difference between bme and bmp readings in the same aircon'ed room and thats closer to the mercury bulb . are cheap ebay things always a bit dodgy?

[towlerg]

"are cheap ebay things always a bit dodgy?" not in my experience, most seem surprisingly interested in protecting their feedback score. Try email seller thro ebay and explain the mistake.

[richard]

Try email seller thro ebay and explain the mistake.

did that , even though i have had the boards for 2 months or more , got a full refund within a couple of hours.
quite surprised in a good way

[HenrikOlsson]

Richard,
Your change to the "cast routine" saved some 400bytes worth of code space and probably also executes faster. Thanks!

Yeah, both of my sensors reports temperature which I believe to be 2-3°C above actual. I don't know if it's due to self heating of the sensor itself, the PCB assembly or something else but the fact that they run different code but both reports values very close to each other makes me fairly confident in the code.

Just now when I started it up again, the humidity reading was way high, around 70%.
A restart fixed it and it's now around 42% which is more inline with the other sensor. This seems to happen now and then and I'm not sure what's going on.

/Henrik.

[Ioannis]

Amazing piece of work by both of you! Thanks a lot for sharing!

Ioannis

[richard]

due to self heating of the sensor

seems possible , the fact that the bmp ver is less "hot" tallies with its lower power use [hum sensor nearly doubles the consumption]

my esp code uses forced mode letting it sleep between readings and fares no better anyway, so maybe it is what it is

Just now when I started it up again, the humidity reading was way high, around 70%.

data sheet says writes to config reg 0xf5 may be ignored if device not in sleep mode, maybe por does not always achieve that.
cannot say i have seen any issues with humidity readings from esp code.
the pressure readings are consistent within 2hpa spread across the chips i have


i find just reading the config reg 0xf5 can cause the device to stop responding completely some times