Most of mobile networks allow to make a distress call on special number like 112 even if you have no money on your plan (actually even if you have no SIM-card and not authorized in mobile network).
So I want to build mobile-enabled first aid kit which will activate distress call wen it unsealed and providing ability to send your position to emergency service operator.
Because of mobile network limitation I will keep it low-tech as possible. Not every place have a good GPRS/EDGE/LTE coverage. Even more - if we want to keep it free of charge we can't use mobile data transfer at all.
On other hand we need to transfer only very small amount of data - only two coordinates. So old-good DTFM looks suitable.
Project page (in Russian):