Hi
I am playing now with I2c. For start I took BPM085. Great instruction at http://dominion.thruhere.net/koen/cms/using-the-beaglebone-as-a-weatherstation
Well I got everything working great, I am reading temp as well as pressure values from:
/sys/bus/i2c/drivers/bmp085/3-0077/temp0_input
/sys/bus/i2c/drivers/bmp085/3-0077/pressure0_input
Great, that was easy, but reading is quite off.
Question:
Is that value the value with all calibrations?
There is 11 calibration factors in data sheet of BMP085 that need to be retrieved from the device and use for some complex calculation.
Thanks
Robert
Hi
I am playing now with I2c. For start I took BPM085. Great instruction at http://dominion.thruhere.net/koen/cms/using-the-beaglebone-as-a-weatherstation
Well I got everything working great, I am reading temp as well as pressure values from:
/sys/bus/i2c/drivers/bmp085/3-0077/temp0_input
/sys/bus/i2c/drivers/bmp085/3-0077/pressure0_input
Great, that was easy, but reading is quite off.
Question:
Is that value the value with all calibrations?
pressure is relative to 0m above sea level. I.e. if you aren't, the reading is different from the weather radio.
There is 11 calibration factors in data sheet of BMP085 that need to be retrieved from the device and use for some complex calculation.
if you have a driver similar to the one used in the GTA04 the calculations should have been already done by the kernel driver.
Finally: it is possible to damage the BMP085 during soldering. Then, you get a temperature reading of e.g. 193 C at room temperature.