Library for BPM085 pressuere sensor

Hi,

I would like to connect a BPM085 sensor (I2C) to a maple mini. I managed to get a 1306 OLED working on I2C. So I think, the basic wire() communication is working.
If I connect the two modules to an Arduino they work. So I think, it has something to do with the library

Does anybody work already with the BPM085?

Andreas

P.S. I tried this library: https://github.com/adafruit/Adafruit-BMP085-Library

I have it (bmp180 3.3Volt version of the 085) running on the Maple Mini with ILI9341 color TFT. Should not be a big issue to cut out the TFT stuff and add back the OLED.
The pinouts are in the source files.
https://www.hackster.io/rayburne
Specifically:
https://www.hackster.io/rayburne/color- … time-clock

Ray

I tried your library and it works! Because I develop on Arduinos and Maple I included it in the C:\Program Files (x86)\Arduino\hardware\Arduino_STM32\STM32F1\libraries\BPM085 folder beacuse it seems to be STM32 specific. I had to create also a folder for the I2Cdev library and to change the references.

Unfortunately, the IDE does not have a “hierarchy” where it starts with the most specific library and it took the “normal” one in the sketches directory. So, I had to delete the one in the sketches library. Later I will put it where it belongs in the Arduino hardware specific folder.

Interestingly, your library uses I2C channel 1 and the Adafrout OLED library uses I2C channel 2 on Maple Mini. Very convenient for me.

My plan is to compare the reading of the BPM180 with a GPS on my bicycle.

Thanks
Andreas

Spiessa wrote:
<…>
Unfortunately, the IDE does not have a “hierarchy” where it starts with the most specific library and it took the “normal” one in the sketches directory. So, I had to delete the one in the sketches library. Later I will put it where it belongs in the Arduino hardware specific folder.

Hello Ray,

Have you by chance gotten a hold of the new BME280 yet? I haven’t even seen much of an Arduino library, but it’s an interest update to the BMP180 as it has temperature, pressure and humidity all built in and it native 3v logic. Seems like a natural fit for the STM32. I am tempted to order one up, but I like to test new stuff on my trusty ‘ol AVR Arduino boards… Of course they are all 5V, SO I would either need to whip up some level shifting or a 3.3v AtMega chip.

BME280 library here
https://github.com/embeddedadventures/BME280
About 20$
http://www.embeddedadventures.com/bme28 … -1022.html

mrbwa1 wrote:Hello Ray,

Have you by chance gotten a hold of the new BME280 yet? I haven’t even seen much of an Arduino library, but it’s an interest update to the BMP180 as it has temperature, pressure and humidity all built in and it native 3v logic. Seems like a natural fit for the STM32. I am tempted to order one up, but I like to test new stuff on my trusty ‘ol AVR Arduino boards… Of course they are all 5V, SO I would either need to whip up some level shifting or a 3.3v AtMega chip.

The BME280 seems somewhat overpriced at the moment.

I have some BMP180 modules, which only cost a few dollars, but the 280 seems to be almost $20.
This cant reflect the true price of the sensor. I suspect the price will drop a lot as more people start to make those module boards.

Re: AVR 328 on 3.3

I have some 8mhz 3.3V pro mini boards.

I tried to run one of my 5v 16mhz boards on 3.3V but it didn’t seem to work, but it doesn’t do any harm to try.

RogerClark wrote:The BME280 seems somewhat overpriced at the moment.

I have some BMP180 modules, which only cost a few dollars, but the 280 seems to be almost $20.
This cant reflect the true price of the sensor. I suspect the price will drop a lot as more people start to make those module boards.

Re: AVR 328 on 3.3

I have some 8mhz 3.3V pro mini boards.

I tried to run one of my 5v 16mhz boards on 3.3V but it didn’t seem to work, but it doesn’t do any harm to try.

Ray,

It was some time ago, but I think it was a pro mini, which I tried and I don’t think it has a regulator
If I get time I’ll try it again.

RogerClark wrote:Ray,

It was some time ago, but I think it was a pro mini, which I tried and I don’t think it has a regulator
If I get time I’ll try it again.

Ray,

OK. Thanks for the tip. I suspect I was feeding into the regulator input. I’ll need to test again, as I think I have a need for a very small uProcessor board soon. (and the Maple mini etc is probably too big)

I have a couple 328p chips programmed to run @ 8MHz off the internal clock, so I would like to try that.

Roger, I see Adafruit has a BME280 breakout for about $20, but it includes a 3.3V regulator and level shifting. The standard BME280 breakout is showing up on eBay for about $10.

My interest is that It’s all in 1 package and the older BMP180 can run off of 1.8V and the datasheet from the BME268 supports this. It means I could run a bare 328p chip/ BME280 / nrf24L01 ensor off of 2 AA batteries and not really have to worry too much about voltage regulation. The darn DHTxx sensors I have all like to be above 3V, so I have been designing a circuit with a low draw 3.3V regulator and 3 AA batteries to compensate.

Of course, an STM32 or even an ESP8266 running at 3.V with the BME280 would make for a nice package; the STM32 might have enough power to build a self-contained Density Altitude calculator, or at least I could build some nice in car or hiking weather/altitude readouts.

2xAA or 1 LiFePO4:

I have not implemented low-power 328 level power savings, but on my to-do list:
https://www.hackster.io/rayburne/smells … o-pro-mini

Ray

mrburnette wrote:2xAA or 1 LiFePO4:

I have not implemented low-power 328 level power savings, but on my to-do list:
https://www.hackster.io/rayburne/smells … o-pro-mini

Ray

mrbwa1 wrote:
<…>
I built almost the same project, but using the 0.96″ Oled. I had it running on a 328p chip, but shelved it before I got the power savings enacted. Actually, I have code for the Oled version, and code to report via the MySensors libraries back to a base station (another half-finished project).

My ultimate goal is a portable unit I can take camping and run off a couple AAs, or even on of those solar battery banks. I have a couple of the solar lamps they sell for the garden (a singe AAA one and a couple LiPo ones) to try and hack the power feed from.

I eill do a little more reading on the BME280 and may just order one of the $10 breakout boards to play with.

I got a BMP280 and compared it with the BMP085 and BMP180. My application is to measure small altitude changes.
If you are interested, the comparison is on youtube:

https://youtu.be/DXGtw0zpOqY

P.S. I measured much better results with the BMP280 for my application.

Andreas

Very interesting, 5% off for the new sensor. Any chance the inside ambient temperature affected the prototype? I know it should be compensated, but … just thinking outloud.

(Around my house, upstairs vs downstairs is at least 5F to 6F and not linear, more a step function.)

Ray

Thanks for sharing

Very interesting ! Thanks !
With the BMP180, is the offset is way larger ?
(because, as you said, BPM280 are much more expansive)

@Ray, as you mention, the formulas used to calculate altitude takes temperature into account. I did also some tests where I simulated constant temperature, but the curves were not very different for the small altitude changes. Maybe, this is because temperature changes are much smaller here, we measure in Celsius
The used formulas are given by Bosch in the datasheet.

@martinayotte, I do not understand your question. Maybe you pose it a little different?

Maybe, this is because temperature changes are much smaller here, we measure in Celsius

OK, that is too funny; I almost spewed my coffee on the PC!

Ray

Spiessa wrote:@martinayotte, I do not understand your question. Maybe you pose it a little different?

martinayotte wrote:
<…>

I mean, did you got chance to experiment with the cheaper BMP180 ?

My project is to measure power needed to drive a bicyle. The BME280 gives me the information for one component: The difference in altitude.
This was only the firs step. In addition, I have to measure wind speed and true speed. So I will continue to experiment with these sensors and will create updates on youtube. I expect also more data about the precision of the BME280. I decided to pay the additional price because its results were much better.
Andreas