Using SMS for remote control
Hi,
I am an irregular contributor to this board, but pop back here every now and again when I have ideas buzzing around my head. I noticed this thread regarding the use of a mobile phone for remote control, and like the simple idea of using an LDR to detect when the phone is ringing. It would be great for certain projects, but I have found that even on very old PAYG phones, I still get 'random' sales calls and also wrong numbers, which could play havoc with the controlled devices.
I was trying to think of a more 'sophisticated' method when it occurred to me that many phones have a connector on the bottom/side which is used for syncing with PCs, etc. It turns out that many common phones have a simple serial connection included in the port that can be treated as a modem to communicate with the phone using AT commands. It occured to me that the Picaxe should be able to communicate with this type of phone, and sure enough, someone has beaten me too it (almost!); I found a fairly detailed article about using an old mobile phone to receive SMS message which can then be read by an ATtiny12 microprocessor. I can't see why a Picaxe is not up to the job!
http://www.riccibitti.com/tinyplanet/tiny_article.htm
A little Googling turns up suitable phones; I just searched for the model number of various old phones that I have lying around, along with the text "rs232 cable", and if an RS232 cable is available for the phone, then it pretty-well must have an RS232 port!
Further thoughts include the fact that a Windows Mobile phone can have applications written for it which can read / send / process SMSs and emails (and access the Internet), and if interfaced to a Picaxe could be utilised for some very sophisticated data logging and remote access purposes.
Considering the cost of an old mobile phone (often free) and the ability to receive SMSs for free (and often send them free via the Internet), there appears to be a lot of potential here. It's going to be a summer holiday project for me (I'm a teacher), but perhaps the above info and thoughts could be of use to someone else in the meantime.
I apologise if these issues have been discussed before in this forum, but I did have a quick look without success.