I recently acquired two AT&T micro SIM cards from family members trading in old iPhones and I'd love to use them as a way to learn something new computer science-wise. I'm a high school senior with experience in Java and Obj-C, but I haven't had much experience working with coding for external hardware, which is why I thought this could be a good opportunity to try some stuff out. Does anyone have any ideas for projects or hacks that I could try, or any good resources I should look to? Thanks