Hi all,

I am wondering if anyone has any experience with SMS sending units...this would come under phone modding I believe. I have seen for sale units of which run on a 12 volt input, you tell the person selling the unit which phone no you would like the text message sent to, when you put 12 volts across the load side of the unit it then sends a text message every 6 seconds unless you remove the voltage from the load side...if you want to change the phone no (some units can send to 4 different numbers) the owner can update the new number/s remotely some how.

I am wondering if anyone knows about these, how they are made or if anyone could tell me a forum that might be able to point me in the right direction.

Thanks

I presume you are talking about GSM alarm and tracker units.

If so they vary in complexity, from simple units which forward a message stored on the SIM to a number in the SIM directory. Through units which connect to a PC and units with an LCD display and keypad.

Generally, they are designed to be fitted professionally but are for sell from DIY security sites.

They use 12volts because that is what alarms use for their output.

Hi prking..

Ya im talking about GSM alarm units..I am looking to buy these as raw units..so I can set the phone no/s they send to and from myself. I will then add the trigger contactors, power source, relays etc.

Do you know of anyone who sells them in this format?

I'm not exactly sure what you are after.

As I say above, the GSM alarm senders are very widely available and easily programmable.

If you are after the GSM modules with no 'supporting' circuitry then the major manufacturer is Siemens and you can buy them in small quantities from distributors like farnell.