MultiWii Controller

I recently purchased an SK450 quadcopter and dead cat conversion kit from Hobby King along with a KK2.1.5 controller board.

After checking out some of the MultiWii websites I thought it should be fairly simple to make a MultiWii board from an Arduino Nano that can make use of all the relevant guidance chips.

I intend to make use of the latest release of the firmware from which at the time of writing is version 2.3.

I like the idea of the All-in-One Pro controller, however I don’t so much like the $50.00 (£30.00) price tag, and even with this controller, GPS is still add-on functionality.

I recently purchased a couple of Arduino Nano boards from ebay for $6.06 (£3.65) each.

a couple of 10 Degrees of Freedom (DOF) boards for $10.28 (£6.19) each.

This board has the following modules: L3G4200D 3 axis gyro, ADXL345 3 axis accelerometer, HMC5883L 3 axis magnetic field and BMP085 for barometric pressure.
A GPS antenna for $15.98 (£8.99)
and an I2C to serial interface for the GPS module for $5.59 (£3.34)
These last 2 items, I would have needed to buy for the All-in-One Pro controller as well, so will not be included in any costings.
The schematic for the controller is actually pretty straight forward.
Most of the connections are simply one-to-one mappings with the Arduino Nano.
I have allowed for all the normal flight controls, 8 motors, camera gimbal pitch and roll, as well as 3 I2C connections, the 5 pin one being for the 10DOF board, one of the others will be for the GPS, the spare could be for an LCD screen or some other functionality.
The board can also be implemented with a one sided implementation and is only 1.85 inches square (47mm).
Even if you choose not to use an earth plane, there would only one cross over wire, connecting ground pin of BRL (Bottom Rear Left Motor) with the ground pin for C-R (Camera Roll).
I may yet make the board slightly bigger to allow for mounting holes, however I am sure it will still be under 5cm, which means it would only cost $9.99 for 10 from Itead Studio.
The board is also simple enough for DIY etching or CNC routing.
Total cost per board (assuming I use Itead Studio), including the 10DOF board and Arduino Nano is about $14.00 or £8.45, I could make 3.5 of these and still have paid less than for the All-in-One Pro.
The final design for this board will be posted on my Electronics Projects Blog.

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