The goal being to have a moteino ( arduino + RFM69W transceiver ) communicate with other 433MHz devices. I first thought that a 3.5 mm audio jack would be ideal to provide serial data transfer between the smartphone and the arduino as this would work on iphone and android phones. But I’m worried about how the information from the audio jack is interpreted and possible problems with equalization and timing. I’d like to avoid a TI CC3000 Wifi Module because of the costs so now I’m leaning towards using the Nordic Semiconductor’s NRF24L01 as a bluetooth transceiver between an android phone and arduino. I don’t think this is possible with an iphone because the bluetooth protocols are proprietary. Anyway, this is something I’ve been thinking about ever since I started fooling around with the RFM69W for home automation. If I could build all of this into a cell phone case I think it would be pretty cool to text and control via 433MHz on your smartphone.