Hi everybody,

First of all, I apologize in advance if the questions I'm gonna ask here have already found an answer, either on the Web or on diydrones, I've searched for quite a while before posting, but I may have missed something. I also apologize for the possible english mistakes.

I believe a small introduction will be necessary to understand the context in which I'm asking those questions, so here we are:

I'm a french computer science student at EPITECH, and for our final project, 5 other students and myself are working on an autonomous Quadcopter Squad, that will (if everything goes well) fulfill various tasks, such as area mapping/surveillance for example, using a mesh network to communicate together.

Our system is mainly composed of a Web Application on which you set the main details of the "mission" (the area in which the Quadcopters will fly, the hardware you need for that mission, etc.) then send it to one UAV, who whill then send  the details to the whole squad, and let's go.

Our main problem now is to choose the hardware the UAVs will be composed of : our system will be embedded on Raspberry Pis, who will then communicate with the flight controller to allow the Quadcopters to fly.

The OpenPilot solution seemed to be good enough in the beginning, but is in fact not safe enough, so we are now thinking about ArduPilot, but before definitely choosing ArduPilot, we want to ensure their won't be problems in the future, so here are a few questions we'd like to answer :

• There are (historically) several types of card Arduino-Based, are the schematic of those card available somewhere in the case we would like to develop our own flight controller card (with, for example, one more USB Interface, some LEDs, etc...), while still keeping it compatible with the actual firmwares ?
• We want to define the most adapted flightcontroller for our project : as I said, we're focused for now on quadcopters, and want it to be Raspberry Pi compatible. Also, we are students, so the price is "a bit" important. Knowing that, could you help us guide our choice ?
• In the case of the use of an ArduPilot card and a Raspberry Pi, are there some hardware component inbetween ? (Resistor, Condenser, CAN Bus, etc. ?)
• What are the most advanced implementations of MAVLink ? What about their integration in an existing CLI project ? (What I mean here is, without any graphical library such as GTK, SDL, etc.)
• For the Raspberry Pi again, what about the compatibility and the porting on ARM architectures ? Is ArduPilot fully compatible with the ARM Architecture ?
• Finally, what are/are there some well-known flaws in ArduPilot ? Any gaps in the project we should be aware of ? What are the unstable/still in development points ?

Here are all the questions we need help with.

Thanks in advance for your time and your answers, and if you ever need any precisions, don't hesitate to ask.