Low cost (under $2) Level convertion modules used to interface 3.3v router UART with a 5v FTDI USB to TTL breakout board (or arduino). No 10k pullup resistor needed! I am assuming this method will work with any of the gpio stuff (including i2c) ... but I haven't confirmed this yet.
this one I haven't tested yet! ... probably still need pullups on the router side ...
(Last edited by sfranzyshen on 3 Nov 2013, 02:11)