guix:
Can someone answer these questions please:I would like some infos about shields. For example with ethernet shield + touchscreen shield, how am I supposed to plug those, if they both need same pins? How arduino can route to the correct shield? I don't understand.
The shield concept just passes all the pin signals vertically up through how many shields might be attached. And it is a real problem if multiple shields utilize the same I/O pins, that is a conflict that no arduino board nor software can solve. One just has to research careful each shields documentation about I/O pin usage to see if there will be a conflict with the ones you want to combine into a single application or project. Also one has to research how much current each shield requires such that their combined current consumption doesn't exceed what the arduino board can safely supply. Sometimes there is also a 'I must be the top shield' problem where you can't stack two or more together because of mounted displays or user switches, etc. The shield concept as defined and used in arduino is really not a well thought out system usable for larger projects, it really works best when you are dealing with just an arduino board and a single shield board.
Also, on the "adapter shield" (the thing between the screen shield and the arduino), you see there are pins at the sides, I think I've read that they are unused: are they just used as supports for the weight?
I haven't researched an 'adapter shield', so can't pass on any information.
What is the typical wire diameter that I must use? And what type of wire, eg for plugging into pins, do I need "full wire" or can I use a "wire with many fibers"? And can I use the same type of wire for plugging into pin and soldering?
The shield connectors were designed to interface with .025" square pins. Solid conductor ('full wire') of the proper size is the best wire to use. Stranded wire ('wire with many fibers') is a bad choice as the ends spread out over time and reuse and can cause accidental short circuits. There are also prefab 'jumper wires that are popular for wiring from arduino shield pins to solderless breadboards. Example: Jumper Wires Standard 7" M/M - 30 AWG (30 Pack) - PRT-11026 - SparkFun Electronics
I'm waiting for those answers so I can finally buy, without making a mistake (I hate wasting money). Sorry if I sound stupid, I'm beginner and french.
You don't sound stupid, just rather new to the hobby. Few like to waste money, but I wouldn't waste too much time ( which you never get back) on the lower cost buying decisions, we all learn by experiance and making purchasing mistakes now and then is part of that.
But so sorry about the French part, can't help you with that.
Lefty
