BMP085 Readings off; used with Digistump Digix

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tech500
 
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BMP085 Readings off; used with Digistump Digix

Post by tech500 »

Adafruit_BMP085_Unified library example used with Digistump Digix.

BMP085 is consistently off on readings; for example, BMP085 readings 29.33 in. Hg. and 998.39 mb compared to local NWS office readings of 30.33 and 1028.20 mb. Differences are 1.00 in. Hg. and 34.81 mb.

Digix = 84 MHz Clock Speed
32-bit ARM Processor (AT91SAM3X8E)
Arduino compatiable

Same sensor on the Arduino Mega 2560 are much closer --only off a few hundredths; so I believe the sensor is not defective.

Any recommendations?

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Franklin97355
 
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Re: BMP085 Readings off; used with Digistump Digix

Post by Franklin97355 »

Any recommendations?
I'd check your code to make sure you are doing the math correctly. Check the raw output to see if it is close between the two processors.

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tech500
 
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Re: BMP085 Readings off; used with Digistump Digix

Post by tech500 »

Math looks correct; readings are close to expected conversion results. Conversion math verified on the Internet; only reference I have currently.

I am wondering if the library needs to tweaked for the Digistump Digix processor speed.
Also, I2C bus from BMP085 Sensor is going to level-shifter, then Digix.

Has anyone used the Adafruit_BMP085_Unified library with the Digistump Digix? Were the Barometric Pressure readings close to NWS readings?

William

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