Hi All,
So it appears several of you have played with the BME280 chip. (Posts
below...)
A while back I started a project with the BME280 that I didn't around to
finishing. Basically, A BME280, PIC24, and Serial to USB cable.
The idea WAS to build a temp/pressure/humidity logger for time nuts use.
There's an on board 32Khz crystal, and a few pins intended for PPS input
or similar. The idea was to use a PPS (Or the RTC, or what ever) to
trigger a sample (or every 5 or 10, or any number of PPS's (or
seconds)), and send it up the serial port for logging.
Anyway, I did layout a board and populated three of them, but ran short
of time to get much done with the code. It's been shelved ever since then.
If anyone on the list is interested in collaborating on such a project,
let me know. I've got an extra board populated for anyone interested in
helping on the project.
Dan
On 10/9/2019 12:00 PM, [email protected] wrote:
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From: Adrian Godwin<[email protected]>
Jim mentions the LM34 for sensitivity and LM34 or LM35 for cost compared
with the DS1620. But also look at the BME280 : it has digital measurement
of temperature with 0.01C resolution (50 times better than the DS1620),
costs ?5 on digikey but less mounted on a breakout from ebay, and also
measures pressure. The very similar BME280 also measures humidity.
------------------------------
From: Didier Juges<[email protected]>
The BME series requires a fair amount of code to convert data from the
sensor into human readable data like degrees. I use the BME280 in some
applications.
Personally, for just temperature sensing, I found good old fashion
thermistors to be cheaper and more accurate than most silicon sensors while
requiring a single precision resistor and one ADC channel. When used with a
12 bit ADC, they offer excellent resolution around a relatively small
temperature range, (progressively degrading resolution as you go away from
the optimum temperature) which is ideal for an oven controller. They are
also easy to use in noisy environments.
Didier KO4BB
------------------------------
From: Mark Sims<[email protected]>
The BME280 does temperature, humidity, and pressure. They are very nice.
Beware of BME280 boards sold on Ebay, etc. A lot of sellers ship BMP280s.
One way to tell is the BME280 is in a square package and the BMP280 is more
rectangular.
Also be aware that some BMP/BME280 libraries seem to have some error in their
humidity calculation code and produce incorrect results.
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