I have a Blackberry Torch that needs to send 10 bytes per second to a serial device. The serial device will probably be a basic stamp 2 or other microcontroller. The Blackberry does not need to receive any data.
Is there an interface that will let me do this for less than $50?
Using the Wifi or Bluetooth connections are the obvious choices but those options look more expensive.
I also thought about using the headphone jack to send out different frequencies and an intermediate circuit could convert the sound into bytes, but I'm not sure where to start with that cicuit.