Note: The chips that this board used are no longer in production. We are working on redesigning the board with currently available chips, and we will be sure to make the appropriate updates once everything is together.
The JeeLabs Pressure Plug is a small board containing the Bosch BMP085 barometric pressure and temperature sensor. This tiny sensor communicates directly over I2C. The sensor is exquisitely sensitive, and with some filtering can detect changes in atmospheric pressure as small as a 1 foot change in altitude. It easily detects the difference between holding it at floor level and holding it over at arm’s reach overhead.
The pinout of the pressure plug board is specifically setup to mate seamlessly with JeeNodes, but the 3.3V I2C device can also be used with any 3.3V microcontroller with I2C functionality. Some processing is required to arrive at properly adjusted readings, since the sensing element responds to both temperature and pressure is available by using the JeeLabs “BMP085” class in the Ports library.
The Pressure Plug also makes a fine (3.3V) breakout board for the BMP085 barometric pressure sensor chip, if you wish to use it without a JeeNode. The only thing that is required is a translation of the header signals, DIO is SDA and AIO is SCL.
The JeeNode I2C bus, running at 3.3V, is used as interconnect, with all the power and signal lines brought out to both sides of the board to allow daisy-chaining with other 3.3V I2C devices if need be.
Note: that headers may be soldered on in either direction (parts up or down), just be sure and match the pins up with their proper signals on the JeeNode or microcontroller.
The Assembled Pressure Plug comes with the SMD-sized BMP085 chip and decoupling capacitor already soldered onto the board. Headers for this and all other JeeLabs plugs can be found here (straight) and here (right angle).
The PCB only version contains just the printed circuit board for the Pressure Plug.