I wondered how hard it would be to take a GSM module, couple it with a small querty keyboard and still have a thin form factor.
The advantage to this would be:
- as a separate device, you'd have a battery backup for your smart
- you can turn the phone off and have it check for messages in intervals of say 10mins. This would mean the battery would last a lot longer
- you can use an old green LED screen (or partial updating eink?)
- if it was thin enough you could velcro it to the back of your main phone... or just not carry a phone at all (some people only do SMS and txt to save cash)
I think this is too difficult to do well.
I looked at adapting current phones but I'm finding it's either too big or too new.
An update to this tutorial is needed:http://tronixstuff.wordpress.com/2011/01/19/tutorial-arduino-and-gsm-cellular-part-one/