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3pi Wixel and Compass


I am thinking of expanding my 3pi with the expansion kit, I would like to have a compass and the wixel, but pictures of the m3pi show with a wixel and mbed controller. It doesn’t look like there is much more room in the board for a third accessory. Is it possible to fit a wixel, mbed controller, and compass on the m3pi? Would the expansion set, mbed, wixel, and compass come with everything I need to set up?

Thank you.


Although the m3pi expansion board does not have a specific socket for adding a compass, after adding a Wixel and mbed, there is still some space available for making your own connections to a compass like the ones we carry. The expansion set includes components to make it easy to add an mbed, and a Wixel or XBee, but not a compass. So, adding your own compass would mean you would have to provide your own hardware to make your own custom connections. You would also have to write code (or find it online) to interface with the compass from your mbed.



Okay, I see. So if I get the expansion, the mbed, wixel, and lets say MinIMU-9 v3, then would I just need a 1x5 female header to attach the MinIMU-9 v3 to my pcb and I would be good? Or would I also need a wire to connect the MinIMU-9 v3 to the mbed? Thank you.


There are many ways to physically mount your MinIMU to your mbed expansion board. You could solder male headers on your MinIMU and having it plug into a set of female headers that are soldered into your mbed expansion board, like it sounds like you want to do. If you are only interested in using the magnetometer, you could also probably just get away with soldering some solid core wire directly into the MinIMU’s pins, and either plugging those wires directly into the outermost set of pins on the mbed socket or soldering those wires directly into the m3pi expansion board.

Either way, you will need to make your own power and I2C connections to the MinIMU. (The MinIMU’s SCL and SDA lines should be connected to the SCL and SDA lines of the mbed and the MinIMU is supplied with appropriate power to across GND and either VDD or VIN.)