There is my new 3ds (XL/LL) cradle based on the official one.
I've used 2 "spring pin" that was on an old wireless home phone and an USB wire.
There's 2 model, one without a case and one that fit an Hori Duraflexi Case.
(http://www.bestbuy.com/site/hori-duraflexi-protector-for-nintendo-new-3ds-xl-clear/3331055.p?id=1219577551823&skuId=3331055)
N3DS_Dock_without_cover.stl | 253.0KB | |
N3DS_Dock_without_cover_Part1.stl | 90.4KB | |
N3DS_Dock_without_cover_Part2.stl | 256.7KB | |
N3DS_Dock_with_Hori_Cover.stl | 235.5KB |