I'm going to make a few of the same device, which will be an arduino board and a few other components encased in a ~15cm x 8cm x 5cm plastic project box. All the wiring will be contained in this box and it won't need to be opened (unless something breaks), so I wish to permanently connect everything. I will have to make various y-cables as well as connecting each different components.
Is it best to solder or crimp my wires? It seems like crimping will be much easier (I will have to make up to 10 devices so labour is a consideration) and will be just as robust? I am terrible at soldering in general.
Is there a crimp for a making permanent connection between two wires? I can only find male and female crimps to go into sockets to then plug into one another. But I wish to skip this step and just directly crimp both wires to a single connector (and then heatshrink it). Surely something like that exists?
If you are considering crimping on connectors then plugging them onto/into the Arduino pins/sockets then that is not a good choice for a permanent, long term project. Soldering them, preferably with strain relief, even if it is only a spot of hot glue, would be a better option
Crimping connectors onto wires is a well established and stable solution where the connectors then attach very firmly to the device but Dupont connectors do not fall into that category
Another consideration is your expertise at crimping. Done properly with the proper, usually expensive, tools it is great, but it is all too easy to make a mess of it.
Solder or screw terms are reliable for high vibration / corrosion environments, otherwise gold
plated locking connectors.
If corrosion/vibration aren't issues then pretty much any connector tech. can work fine including dupont (for
instance they are used in computers for things like audio connections to motherboard).
So it depends a bit on how adventurous the box is going to be - if its portable and being lugged around
all the time, vibration is an issue. If its used outdoors, corrosion might be an issue.
[ BTW practice your soldering! ]
You don't provide enough information for us to give you proper guidance. How heavy are the wires? How are they anchored?
If you never plan to go inside, consider this:
Solder to a PCB is best.
Crimped Dupont connectors added so you can remove wiring is great too.