Heading Board (discontinued)
This board is no longer in production, see the Compass Board for a high performanc 3-axis / single-port alternative.
The Heading Board is a small board containing the HDPM01 compass module by HopeRF. For some reason, there is also a barometer and a temperature sensor on this module - which you can ignore if all you need is a compass, i.e. a 2-axis magnetometer. Each of the two magnetometer axes has 12-bit accuracy, and a sensitivity of 512 counts per Gauss. There is a “HeadingBoard” class in the JeeLib library to interface with this sensor and read out all three on-board sensors.
Part of this board uses an I2C bus running at 3.3V as interconnect, but two other signal lines are also needed. These are tied to DIO and IRQ (not AIO, because this board needs a 32 KHz clock to operate, which is generated by Timer 2).
The Kit version includes the PCB and the HDPM01 module, which can simply be soldered on top of the PCB. Note that no 6-pin headers are included.
The PCB only variant contains just the board for the Heading Board. No parts, no headers.
As connectors you can use a Plug Headers set with 10 male and 10 female 6-pin headers, which makes it easy to connect multiple plugs and JeeNodes in a “standard” way. Or you can solder the board directly in place for more permanent use.
The documentation and full design details are freely available.