What have you tried Patrick? What part is giving you problems? Getting the GPS coordinates? Composing the sms Message? Sending the Text message?
A developer has got to be careful doing this as the total message you send as an sms must be < 160 characters total (including spaces). You can't get it working? Where do you think the problem lies?
Here is some additional help:
1) Use the LocationSensor to get either the geocoordinates or the CurrentAddress.
Exploring with Location Sensor in AI2The location sensor object is used to communicate with the global positioning satellite receiver (GPS) in your phone/tablet. When the LocationSensor communicates with the built-in GPS receiver, the GPS can determine the location of your device. The sensor can also work with network/wifi location services. Finding a location using the network uses very different techniques to determine a location. Location means, the device's present latitude and longitude or it can mean your street address.
There are two examples in this tutorial ...read the text, do a tututorial and you will know all you need to know about how the GPS receiver works.
2) Use the Texting component to send the sms message which will include the CurrentAddress or latitude and longitude . Be aware, a Text message needs to be less than 160 total characters (including spaces) so don't get wordy.
There are several SOS app examples in the MIT Gallery that do this. Search the Gallery for SOS or GPS Texting or GPS sms There are many examples of apps of this type, some better than others that send a text message based on GPS coordinates.
An additional item to consider is your Phone sleeping. If it goes to sleep, your messages will not be send, so you need to keep your device screen active while doing this; either keep a finger on your screen, use a Stay Awake routine to keep the screen on at the cost of excessive battery drain and heat your use an extension.
Sending the location is certainly possible. Post an image of your blocks here in the Forum and someone will provide specific advice.
Regards,
Steve