http://playground.arduino.cc/Main/I2CBi-directionalLevelShifterDescribes using mosfets.
I'm curious about the feasibility of this method. Has anyone tried it? It's pretty similar to some solutions I've seen. I just havent seen anyone use the 3.3V pin as the voltage source. Is there any reason this wouldn't work?
For an IIC level converter the only thing 'required' is 2 logic level mosfets (the lower the VGth the lower the low side voltage can be.NXP AN10441 (attached) is a good source of 'inspiration' I've used the circuit from 5 to 3V3 (BMP085) with 2N7000's with good success. the recommended mosfet is an SOT-23 BSS138..Level shifters of similar nature can be found on Ebay too, I bought two for $2.42 "Free Shipping".I thought the price high considering the BOM but the convenience won me over.Doc