My new RPi, Dixie, left the old one, Pixie, with nothing to do. So I decided to branch out into GPIO prototyping and try some DIY data logging, beginning with barometric pressure and room temperature.
Actually I started out with a PiFace interface from Farnell but that doesn’t seem to break out all the GPIO pins, and I needed SCA and SCL for the pressure sensor device I had chosen, BMP180, from ModMyPi.
So I switched to a Humble Pi breakout board and with a little careful soldering I was soon in business. I re-used the new PiFace case, which is deep enough to accommodate the breakout board and its components:
I followed How to set up a Barometric pressure sensor BMP085 on Raspberry Pi with Raspbian which explains how to enable i2c in Raspbian for communication with the pressure sensor. Then I acquired the python support software from Adafruit via
git clone https://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code.git. It was easy to tweak Adafruit_BMP085_example.py script into my own code for logging pressure and temperature to a tab separated text file. I can export that whenever I like and use LibreOffice to produce: