Hi sunesune!
Welcome to MobiFlight!
If you have no knowledge of electronics or programming, then MobiFlight is the place for you.
Some knowledge about electricity, e.g. for the calculation of a resistor for LED or what is GND, you should, however, bring along. You can also work through the tutorials to gain the necessary knowledge about MobiFlight.
You do not have to be able to program. You will also acquire knowledge or knowledge of logic as you work through the tutorials.
Leo Bodnar's interfaces are good when it comes to analog interfaces such as Joystick axes etc. goes. MobiFlight itself can not work with analog axes.
Pookeys works similar to MobiFlight to my knowledge.
OpenCockpit is a system of its own, with I / O cards, bus system etc. If you decide to do so, you are not very flexible, because OC, always OC.
MobiFlight uses the Arduino MEGA 2560 R3, either as a brand or as a clone (from China). As a clone, a mega module costs less than 10 euros, while a MEGA original is available from 30 euros. Many have had very good experiences with the China clones here.
If you say that the simulator does not need to be 100% accurate, you'll quickly find that you throw everything that does not reach 100% into the garbage. The claims increase with your experience!
You should experiment a bit first and see if you like MobiFlight. Buy a few parts, a plug-in board, a 5V power supply and a few things you plan to use (switches, encoders, rotary switches, LEDs, resistors).
As for MobiFlight, you can always ask questions to the community here.
Remember: there are no stupid questions, just stupid answers
I hope I could give you a brief overview in the near future. Do not hesitate if you have questions.
Edit: I forgot to mention that you need FSUIPC by Pete Dowson for MobiFlight. For starters, it is enough to use the freeware version. You should buy a registration later.
MobiFlight works in two directions. Once e.g. from a switch to MobiFlight, MobiFlight to FSUIPC and FSUIPC to the simulator. These are the inputs. Conversely, the outputs are read out and displayed, ie LEDs, 7-segment displays, LCD.
You can download FSUIPC here:
http://home2.btconnect.com/petedowson/
For the FSX you take the version 4.xxx and for the P3D from version 4.4 the version 5.xxx